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Subsections

Virology

Virology is the study of viruses and virus-like agents: their structure, classification and evolution, their ways to infect and exploit cells for virus reproduction, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy. Virology is often considered a part of microbiology or of pathology.

Diseases caused by viruses

Arboviruses

Oropouche virus

It is a tropical viral infection, a zoonosis similar to dengue fever, transmitted by biting midge (species Culicoides paraensis) and mosquitoes from the blood of sloths to humans. It occurs mainly in the Amazonic region, the Caribbean and Panama.

Venezuelan equine encephalitis virus

It is a mosquito-borne viral pathogen that causes Venezuelan equine encephalitis or encephalomyelitis (VEE) can affect all equine species, such as horses, donkeys, and zebras. After infection, equines may suddenly die or show progressive central nervous system disorders. Humans also can contract this disease. Healthy adults who become infected by the virus may experience flu-like symptoms, such as high fevers and headaches. People with weakened immune systems and the young and the elderly can become severely ill or die from this disease.

Dengue virus [1]

Dengue is a mosquito-borne infection that causes a severe flu-like illness, and sometimes a potentially lethal complication called dengue haemorrhagic fever. Dengue is transmitted by several species of mosquito within the Aedes genus, principally Aedes aegypti which acquired the virus an infected persons or monkeys. There is no vaccine. Prevention concentrates on reducing the habitat and the number of mosquitoes and limiting exposure to bites. The incidence of dengue has grown dramatically around the world in recent decades. Some 2.5 billion people, two fifths of the world's population, are now at risk from dengue.

Laboratory diagnosis

Laboratory diagnosis methods for confirming dengue virus infection may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these techniques. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 4-5 days. During the early stages of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis.

Diagnostic methods

Virus isolation, genome detection, NS1 detection, serology IgM, serology IgG, haematological tests (Platelets and haematocrit values).

There are four serotypes of dengue virus (DENV-1 to 4) causing different symptoms, such as Dengue haemorrhagic fever. Lima et al 2011 investigate the usefulness of NS1 capture tests as an alternative tool to detect DENV in tissue specimens from dengue fatal cases occurred in 2002 in Brazil. The authors evaluated three tests for NS1 antigen capture: first generation Dengue Early ELISA, Platelia NS1 and the rapid test NS1 Ag Strip. The NS1 Ag Strip achieved the best results of all three tests. The authors concluded that DENV NS1 capture assay is a rapid and valuable approach to postmortem dengue confirmation in different tissues. [2]

Polyclonal antibodies against Dengue virus Protein expressed in E.coli [3]

The non-structural 1 (NS1) protein plays an important role in dengue diagnosis. It is present as serum antigen in both primary and secondary infections. Alonso and colleagues 2011 describe a polyclonal antibody produced from the properly folded E. coli recombinant NS1 (rNS1) protein which could detect 100% of the Dengue virus 2 (DENV2) in infected patients. The study demonstrates the correctly folding rNS1 that maintains its structural and immunogenic properties, enabling an early diagnosis.

Testing saliva for Dengue antibidies in early phase of regions with secondary infections [4]

Yap and colleagues 2011 used an antigen capture anti-DENV IgA (ACA) ELISA technique to test saliva samples for Dengue antibodies. The sensitivity within 3 days from fever onset was over 36% in primary dengue infections, and 100% in secondary infections,within 1 Day after fever onset. Testing saliva is much cheaper then performing tests on venous blood. The authors suggest that saliva should be tested to detects dengue virus (DENV)-specific immunoglobulin A (Ig A) early in the phase of a dengue infection.

Yellow fever

It is also endemic. Nonhuman primates are the principal reservoirs of the disease during its sylvatic cycle. Vaccination is an essential means of protection against yellow fever for both the local population and visitors. Aedes aegypti mosquitoes in Amazonian urban centers pose an ever-present risk for yellow fever transmission and are also responsible for the high incidence of dengue.

Viral hepatitis

It is an acute liver disease with varying severity caused by the hepatitis A virus (HAV), contamination by fecal matter and ingestion of contaminated food or drinks.

Hepatitis A virus

The delay of incubation oh hepatitis A virus is around thirty days. The severity of the clinical signs vary from asymptomatic case in children younger than 6 years old with cases of acute or fulminant hepatitis. Fecal-oral parental, sexual, salivary or urinary transmissions are reported. There is no specific curative treatment but a vaccine is available. Hepatitis A virus can resist to different physical and chemical treatments, and can survive in different kind of environment for a long period.

The diagnostic by cellular culture or ELISA is not adapted to the detection of Hepatitis A virus in environmental or food samples. Molecular techniques (real time RT-PCR) are the methods of choice for Hepatitis A detection after extraction and viral RNA purification from the sample.

Hepatitis B virus (HBV)

Contamination by contact with infectious blood, semen, and other body fluids from having sex with an infected person, sharing contaminated needles to inject drugs, or from an infected mother to her newborn.

Hepatitis C virus (HCV)

Contamination by contact with the blood of an infected person, primarily through sharing contaminated needles to inject drugs.

Hepatitis D (HDV) virus

Contamination by contact with infectious blood, similar to how HBV is spread.

Hepatitis E virus (HEV)

Contamination by ingestion of fecal matter, even in microscopic amounts; outbreaks are usually associated with contaminated water supply in countries with poor sanitation.

Kaposi sarcoma-associated herpesvirus ( HHV-8)

It is the eighth human herpesvirus. It causes Kaposi's sarcoma, a cancer commonly occurring in AIDS patients, as well as primary effusion lymphoma and some types of multicentric Castleman's disease.[5]

Viral infections

The cause of infectious diarrhoea were usually told to be bacterial or parasitic. Only recently, beginning with the 70 decade of 2000 better diagnostic methods have proved that food-borne diseases caused by virus are very frequent.
The most important agents of these diseases are:
Mouth and foot disease virus: is present in all kind of tissues of cattle and swine (Hepatitis A-virus, Hepatitis E-virus phage).


The name of viruses

Animal viruses

Viruses which attack animals were named based on the disease which they caused followed by the word virus, such as influenza virus,poliovirus, human immunodeficiency virus (HIV).

Viruses living on plants

They are named according to the plant they live on, followed by the main symptoms of the disease which they cause, such as tobacco mosaic virus (TMV) tomato bushy stunt virus (TBSV), raspberry ringspot virus. However, plant viruses may infect a variety of other plants, such as the cucumber mosaic virus (CMV)may cause up to 80 sets of symptomn in various host plants.

Bacterial viruses

Bacterial viruses are named by code letters or by a system of letters such as phage λ, Qβ , T2, φX174. These names of bacterial viruses do not follow any rules, and were given by the laboratories which were studying the virus such as the virus MS2 so called because it was the second isolate of a virus infecting male specific strains of E. coli.

Influenza viruses

They can be divided in three types: A, B and C.
Especially the type A undergoes genetic variation. That is the reason why often new strains of influenza arise. These strains are called serotypes because they can be distinguished by serological agglutination tests. Influenza-A-virus: is found in lung of swine. It is the most common type of influenza outbreaks in humans.


Avian influenza A and Newcastle disease

Both affect avian species.Criteria for contengy plans in case of both diseases are found Annexe IV of Council Directive 92/40/EEC of 19.5.1992 and Directive 92/66/EEC introducing Community measures for the control of both diseases, involving poultry producers,operators of slaughterhouses and rendering plants,veterinarians, and diagnostic laboratories.
The Directive 92/40/EEC lays down Community measures to eradicate and prevent the spread of avian influenza on poultry farms should an outbreak occur and prohibits removal of the poultry and poultry products from specified areas such as protection or surveillance zones.
Avian influenza has a high mortality and a rapid spread. Infection occurs through direct contact between the animals or vectors such as man,birds, utensils,transport devices such as packaging materials such as egg trays. Avian influenza (Subtype H7N7)which has caused an epidemic spread in the Netherlands in February 2003 is not infectious to mankind.
There are 15 influenza virus A subtypes that can infect poultry. Vaccination is therefore not possible as there is no cross-immunity. Influenza vaccination is not effective against H5N1 virus. It is intended to avoid H5N1 to cross with human influenza types and become highly infective for humans.

The Incubation period is 8 days and quarantine 21 days.

Bird flue H5N1 becomes more easily transmissible, fear scientists [6]

Chen, 39, a Chinese bus driver tested positive for the H5N1 bird flu virus. He died on December 31, 2011 at the city of Shenzhen near Hong Kong, where more than 19.000 birds were slaughtered and imports and sales of live poultry were banned for three weeks following a positive test for H5N1 at a chicken carcass. Chen had no contact with poultry.

The H5N1 virus rarely infects humans which come into close contact with diseased poultry. However, the mortality among infected people is nearly 60 percent. Scientists fear that the virus is becoming more easily transmissible from human to human. About 120 people had contact with Chen, however, no one become sick so far.

WHO says globally there have been 336 human deaths from 573 confirmed bird flu cases since 2003. Of these, 40 cases were in China, 26 of which were fatal. China’s last case of H5N1 was reported in June 2010 when a women died after exposed to sick and dead poultry.

Avian influenza H5N1 animal- human [7]

The highly pathogenic avian influenza A H5N1 viruses poses a risk to humans because of the endemicity in poultry populations in several countries, such as Asia and Egypt. A reassortment with the H1N1 pandemic strain is possible.

Transmission of the H5N1 virus from poultry to humans is rare, and is attributed to contact with infected blood or bodily fluids of infected poultry via food preparation practices, touching and caring for infected poultry, consuming uncooked poultry products, exposure to H5N1 via swimming or bathing in potentially virus laden ponds; and exposure to H5N1 at live bird markets. Environmental contamination may also occur by inhalation, ingestion, conjunctival or intranasal inoculation of contaminated water, mud, cleaning poultry areas, removing faeces, gathering eggs, using poultry waste/scrap as fertilizer, etc. Inhalation of virus at LBM, or in village/household where poultry have been recently sick or died. Occasional limited human-to-human transmission occur.

The authors stress the importance of collaboration between human and animal health sectors for surveillance, case investigation, virus sharing, and risk assessment is essential to monitor for potential changes in circulating H5N1 viruses

Rabinowitz et al 2010 suggest that direct contact with sick birds is not the only means of human exposure to avian influenza H5N1 virus. The authors stress ther necessity to study the environmental virus persistence, the shedding of virus by asymptomatic poultry and disease pathophysiology in different avian species relative to human zoonotic risk, as well as specific modes of zoonotic transmission, should be determined. [8]

Passerines are more important avian flue transmitter than aquatic birds [9]

Waterfowl are linked with avian influenza, however, Fuller and colleagues 2010 emphasizes that 22 species of song birds and perching birds are also reservoirs of influenza.

The authors point out that the influenza prevalence in passerines is high. These birds share the same habitat as poultry and are more effective transmitters of the disease to humans than aquatic birds. Cloacal samples indicate that the prevalence of influenza in passerines is greater than the prevalence in eight other avian orders.

Data of this study identifies the Great Plains and the Pacific Northwest as high-risk areas for Avian influenza virus. The authors also stress that the amount of harvested cropland are highly significant predictors of Avian influenza virus, because of the reduction of natural habitat available to avian migrants, This is also valid for the first day of the year when a county is snow free and birds may move in.

WHO urges consumer to maintain precautions against avian flu [10] [11]

New cases in China in January 2009

Chinese health authorities are worried with a third case of bird flu. No abnormality was found in poultry farms or agriculture markets where the child where the last case had been in contact with.

Health officials say if there is no avian flu outbreak in poultry and yet there are human cases, a change in the virus might have happened, so that chicken do not get sick, but the H5N1 virus remains deadly to humans.
Another possibility of "silently infected chickens" carrying the virus or transmitting the disease without bird flu-like symptoms.

Precaution

WHO urges consumer to maintain normal precaution against avian influenza, such as ensuring all poultry is well cooked and always washing hands after contact with raw meat.

New case in Egypt

A new human case of avian influenza A(H5N1) virus infection was hospitalized on 10 January 2009 and is currently in a stable condition. The patient had contact with sick and dead poultry. Of the 52 cases confirmed to date in Egypt, 23 have been fatal. [12]

Vaccination against avian influenza of H5 and H7 subtypes in domestic poultry and captive birds [13]

Control measures of the HPAI strain of H5N1 are based on eradication of infected flocks, but increasingly more countries supplement these measures by the use of vaccination which is becoming important to control and prevent the propagation of the disease.

The opinion of the European Scientific Panel on Animal Health and Welfare is intended to support the Commission in the further developments of a vaccination policy and was adopted on 11 May 2007.

According to this opinion, the current EU authorised AI vaccines for poultry such as chickens and ducks meet the relevant quality standards and are thus, safe and effective to be used. However, for other poultry and captive bird species the level of effectiveness of current AI vaccination is not sufficiently known and therefore additional data on the immunogenicity and effectiveness of current and future AI vaccines should be generated.

In general, the use of AI vaccines in poultry should be defined in advance dependant on the epidemiological situation, geographical area and overall risk perception as a preventive, emergency or in endemic situations.

Vaccination may also reduce transmission of AI virus amongst captive and wild birds, having also major benefits for animal welfare as vaccination will prevent them from contracting the disease, death and from being culled during eradication measures.

Silent spread of AI viruses can occur after vaccination, and therefore serological monitoring with DIVA based strategies will be required to detect AI virus transmission after vaccination (shedding of the virus without presenting symptoms of the disease).

Vaccination programmes using vaccines authorised by the competent authority may reduce the potential for human and other mammalian cases of HPAI, where the disease may become endemic. The use of EU authorised vaccines per se is recommended because is safe and has no negative effect on poultry products for consumers.

On the evaluation of laboratory testing methods for surveillance of vaccinated flocks (in particular DIVA strategy), it is concluded that to date only conventional inactivated and recombinant live-vectored vaccines are available for use and can be coupled with a suitable companion diagnostic test.

An intrinsic problem of the DIVA principle is that infections with all AI subtypes (including non H5 and H7) may interfere.

The "DIVA" (Differentiating Infected from Vaccinated Animals) a control strategy for avian influenza infections in poultry is based on the use of an inactivated oil emulsion vaccine containing the same haemagglutinin (H) subtype as the challenge virus, but a different neuraminidase (N). [14]

The "ad hoc" serological test based on the detection of specific anti-N1 antibodies. "DIVA" control strategy may represent a tool for the control of avian influenza infections in poultry to differentiate between vaccinated and naturally infected birds. [14]

Reassortment or point mutations of H9N2 influenza virus is predicted to become a new pandemic, says University of Maryland researcher [15] [16]

The avian N9N2 is endemic and presents occasional transmission to humans and pigs Perez and colleagues 2009 in an article in the Proceedings of the National Academy of Sciences of the United States of America report how the current swine influenza strain formed. The authors write that avian, swine, and human-like viruses combined in a pig to make the new virus. It then mutated to be able to spread by human respiratory. The infection of avian influenza viruses from birds to humans may cause a serious disease, however, the spread from human to human is rare.

A pig can host both avian and human-like viruses where they can combine and form hybrid avian-human viruse. These viruses can infect humans. The immune system is not prepared to fight them because the surface proteins are new. This type of virus can easily mutate to spread quickly and potentially cause a human pandemic.

The authors reverse genetics mutated the H9N2 influenza virus, creating a hybrid human-avian virus. The new hybrid had internal human flu genes and surface avian flu genes from the H9N2 virus. The combination avian and human influenza virus under laboratory conditions was similar to the origin of the swine flu virus H1N1 of the actual outbreak. Ferrets were infected with the virus created by the researchers. The mutated virus was able to spread by respiratory droplets.

Only two mutations were necessary to make the hybrid H9N2 transmissible. A human pandemic of this virus is predictable. Perez suggests that the H1N1 swine flu virus mutated in a similar form as shown with the H9N2 in his research.

The two genetic mutations took place in the lab strain, one on the HA surface protein enabled respiratory transmission between mammals and the other mutation was the site where human antibodies would bind but is different from actual vaccine stocks. The H9N2 is therefore a new candidate for a pandemic.

The authors concluded that the reassortant virus expressing only the hemaglutinin HA and the neuraminidase (NA) of the ferret-adapted virus was able to account for the transmissibility. The currently circulating avian H9N2 viruses require little adaptation to turn pandemic. Aerosolized respiratory transmission may also be caused by others then by the current human H1, H2, and H3 influenza subtypes.

Reassortment may increased pathogenicity of pandemic (H1N1) [17]

Schrauwen and colleagues 2011 report that three influenza A viruses (seasonal (H3N2), seasonal (H1N1), and pandemic (H1N1) 2009) were found to be circulating during the swine flue pandemic which started in 2009. The authors are concerned with the possibility of genetic reassortment between these viruses. The resulting strains my present increased pathogenicity. The authors tested four reassortant viruses determining their replication kinetics in vitro and pathogenicity and transmission in ferrets.

Pandemic (H1N1) 2009 with neuraminidase of seasonal (H3N2) virus resulted in increased virus replication and produced severe pulmonary lesions, while pandemic (H1N1) 2009 viruses containing basic polymerase 2 alone or in combination with acidic polymerase of seasonal (H1N1) virus were attenuated in ferrets.

The authors concluded that pandemic (H1N1) 2009 virus has the potential to reassort with seasonal influenza viruses, which may increase its pathogenicity and maintains the abillity of transmission through the aerosols or respiratory droplets.

Mutations which may affect oseltamivir resistance of influenza A pandemic (H1N1) [18]

Hurt et al 2011 report that I117V mutation in pandemic H1N1 is rare, and was detected in only one isolate from Australia. It confers only a mild resistance to oseltamivir, but combined with H275Y it exerts a synergistic effect of both mutations, increasing the resistance to the drug. The mutation I117M does not confer oseltamivir resistance.

The effect of I117V appears to be mainly caused by an internal cavity of the mutation, which could increase flexibility of neighbouring residues such as E119, R118, and V116 that form part of the drug-binding framework.

The authors stress that functional drug resistance should be considered when studying novel mutations, rather than substitution of aminoacids at the same residue.


Swine-originated influenza A virus known as pandemic (H1N1) 2009 [19]

A novel swine-originated influenza A virus known as pandemic (H1N1) 2009 was first isolated from humans in Mexico in April 2009, the worldwide pandemic resulted in more than 18,000 deaths. Swine, turkeys, ferrets, cats, and cheetahs, were found to have been infected. Transmission from humans to pigs were reported. In August 2010, the World Health Organization stated that the pandemic caused by this virus had ended.

Swine influenza A virus (SIV) belongs to the family Orthomyxoviridae and is a causative agent of respiratory disease in pigs. Three subtypes of influenza viruses are circulating in the swine population globally: H1N1, H3N2, and H1N2. Pigs can be simultaneously infected with avian influenza viruses and human influenza viruses. The influenza viruses can exchange genes between both viruses and produce new variants in pigs. The influenza viruses. Pandemic (H1N1) 2009 is such a triple hybrid that contains swine, human, and avian virus gene segments becoming dangerous for humans.

Yan et al. 2012 describe an outbreak of pandemic (H1N1) 2009 virus in a pig farm in Guangxi Province/China in January 2011, with severe respiratory problems and a death rate of 22%. The virus had high identities to a pandemic strains A/California/04/2009 (H1N1)
.
The sequencing of a partial genome of the HA gene found 10 strains of subtype H1N1 influenza virus, 5 strains of classic swine H1N1, 3 strains of Eurasian avianlike H1N1, and 2 strains of pandemic (H1N1) 2009 virus. Several samples tested positive for HI titers in the serology for pandemic (H1N1) 2009 and others had positive HI titres for SIV (H1N1). Cross-reactivity of pandemic (H1N1) 2009 virus between H1 subtype viruses has been reported , but the higher rate was positive for pandemic (H1N1) 2009 virus.

The data of Yan and colleagues demonstrate that growing and fattening pigs are susceptible to infection of pandemic (H1N1) 2009 virus, no gene reassortment occurred yet, the pandemic virus is currently circulating in swine populations in southern China. Increasing serological surveillance of pigs for prevention and better control of pandemic influenza is urgently needed in China.


Human H3N2 influenza A virus (IAV) infections in swine populations in Argentina 2008 [20]

Cappuccio et al. 2011 reports that the virus isolate in 2008 in Argentina shared nucleotide identities of 96-98% with H3N2 IAVs that circulated in humans from 2000 to 2003. The authors stress the importance of two-way transmission of H3N2 influenza A virus (IAV) and swine influenza viruses (SIVs) between pigs and humans, and call for enhanced influenza surveillance in the pig population worldwide.

Subtype H1N2 influenza viruses in Guandong/China [21]

In China H3N2 and H1N1 swine influenza viruses have been circulating for many years, and in january 2010, one subtype H1N2 influenza viruses was isolated by Kong et al.in Guandong. The complete genome was determined and the strain was called A/swine/Guangdong/1/2010(H1N2). The PB2 and PAsegments were close to avian origin, but NA and PB1 were close to human origin. Kong and colleagues underline the interspecies transmission of avian influenza viruses to pigs. Swine influenza virus (SIV) surveillance is, therefore, important in association with food and mouth diseases in pigs.

Swine origin influenza viruses (SOIV) [22]

Swine influenza viruses (SIV) have been recognized as important pathogens for pigs and occasional human infections with swine origin influenza viruses (SOIV) and A(H1N1) have been reported. in the United States. Shu et al. 2012 assessed SOIV subtypes of samples from human cases and identified these samples as triple reassortant (tr-SOIV) containing genes from classical swine, avian and human influenza viruses. These tr-SOIV, were of A(H1N1), A(H1N2), and of A(H3N2) subtype. These SOIVs were closely related to influenza viruses circulating in pigs but distinct from influenza viruses circulating in humans. Shu and colleagues write that a continued surveillance of the animal-human interchange of these viruses is important.

The 2009 pandemic H1N1 (pH1N1) evolved in pigs by cross reactivity [23]

Nfon et al. found pH1N1 virus several times in Canadian pigs in 2009, together with H1N1 with human genes, the TRIG cassette and an oseltamivir-resistance marker. The authors stress the possibility of reassortment between the NS gene of one of these seasonal human-like SIV (shSIV) H1N1 isolates and the pH1N1 NS virus as both were hound to be homologous. Antigenic cross-reactivity was observed between pH1N1 and conSIV but not with shSIV H1N1. The authors suggest that pH1N1 in pigs were built by reassortment because it had not found before May 2009. A close monitoring is necessary to avoid further epidemics of new strains.

Swine influenza virus antibodies in humans suggest serologic cross-reactivity with antigenically distinct viruses [24]

Serologic studies for swine influenza viruses (SIVs) in humans in Luxembourg were performed by Gerloff et al. 2011. Higher levels of neutralizing antibodies against pandemic (H1N1) 2009, avian-like enzootic subtype H1N1 SIV, and 2007-08 seasonal subtype H1N1 viruses were found in persons whose profession involved contact with swine than controls with no exposures to swine.

The authors, solving the puzzle of positive serology for SIVs in controls not exposed to swine, explain that sequential exposure to variants of seasonal influenza (H1N1) viruses may have created serologic cross-reactivity with antigenically distinct viruses and do not correlate with infection.

Newcastle disease or infectious bronchitis

It is caused by a Virus of the family Paramyxoviridae, genus Rubulavirus. The disease does not pose a risk to human health. Poultry and egg products are safe to consume. Human infection with Newcastle disease virus is extremely rare, and usually occurs only in people who have close direct contact with infected birds The virus causes only mild, short-term conjunctivitis or influenza-like symptoms. The use of Newcastle disease virus as a treatment for cancer has been suggested.

Avian influenza virus infections are widespread in wild birds, especially ducks, migrating waterfowl are a significant source of avian influenza viruses. That is why poultry should not be kept outdoors to avoid contact with wild birds in epidemic regions.
Disinfection with normal detergents and disinfectants is sufficient. Heating and drying inactivates the virus. Heating of contaminated houses for several days is effective. Organic material and manure must be disposed properly as it can protect the virus from disinfectants allowing them to survive for over 100 days.

To date, a large number of human infections with the H5N1 virus have been linked to the home slaughter and subsequent handling of diseased or dead birds prior to cooking. These practices represent the highest risk of human infection and are the most important to avoid.

People working or living in close contact with poultry, such as poultry farm workers, or family with household poultry breeding are at high risk if diseased animals are present. The virus is found in secretions of the respiratory tract, and most of all in manure.

Human infection occurs mainly by inspiration of dust particles containing viruses, and handling infected animals omitting handwashing.

Avian influenza A viruses infecting humans since 1997

Virus Occurrence) Cases
H5N1 Hong Kong, 1997 Infection occurred in both poultry and humans. It was
    the first detected direct avian influenza
    transmission from birds to humans.Six persons died.
    18 cases were reported. 1.5 million chickens were
    killed in order to control the epidemic
H9N2 China and Hong Kong, 1999 Two children were infected. They recovered.Several
    human H9N2 infections from mainland China
    were reported in 1998-99
H7N2 Virginia,USA, 2002 One person had positive serological reaction
    to H7N2 following an outbrake of H7N2 in the
    Shenandoah Valley area
H5N1 China and Hong Kong, 2003 Two case occurred among travellers from Hong Kong
    to China. One Person died. Another death due to
    respiratory illness from the travellers group was not
    serologicallyly cleared.
H7N7 Netherlands, 2003 Outbrakes of influenza A (H7N7) in poultry pigs
    and humans. 89 were infected by H7N7in association
    with the poultry outbrake. One death of a veterinarian
    who visited an infected far was reported. Three possible
    transmissions from poultry workers to family members
    occurreded. Since that time no other infection was reported
H9N2 Hong Kong, 2003 One child was infected by H9N2. It recovered.
H7N2 New York, 2003 One patient was medicated in relation to
    an infection with H1N1. In March 2004 further tests
    has showned that it had been H7N2
H5N1 Thailand and Vietnam, 2003 Highly pathogenic influenza A
    (H5N1) was reported. Human cases are still happening there.
H7N3 Canada, 2004 Human infections among poultry workers
    were due to an outbreak of H7N3 in poultry.The
    illness consists of eye infections.
H5N1 Asia,Thailand Avian influenza in Turkey,Romania and Russia


The signs of avian influenza

Detectable antibody titre to AI. AI, respiratory, enteric, reproductive or nervous system disease, decreased food consumption and drops in egg production, coughing, sneezing, ruffled feathers, swollen heads, nervous signs like depression, and diarrhoea.
There are three pathotypes of Newcastle disease viruses (NDV's)known:lentogenic, mesogenic, and velogenic.
The Velogenic Newcastle disease is the most severe of Newcastle Diseases.

Clinical signs

Respiratory and/or nervous signs: gasping and coughing,drooping wings, dragging legs, twisting of the head and neck, circling, depression, inappetence, complete paralysis. Partial or complete cessation of egg production. Greenish watery diarrhoea. Swelling of the tissues around the eyes and in the neck.

Clinical signs of human infection

Symptom may appear up to two weeks after infection. They are similar to a serious cold: Fever head- and throat pain, cough, respiratory complaints, pneumonia, additional stomach and gut complaints, and abnormal liver test results, bloodcells and platelets count decreases. Some patients kidney failure.


WHO Recommendations Regarding Avian Influenza

WHO recommends that travellers to areas experiencing outbreaks of highly pathogenic H5N1 in poultry should avoid contact with live animal markets and poultry farms. Large amounts of the virus are known to be excreted in the droppings from infected birds. Populations in affected countries are advised to avoid contact with dead migratory birds or wild birds showing signs of disease.
Direct contact with infected poultry, or surfaces and objects contaminated by their droppings, is considered the main route of human infection. Exposure risk is considered highest during slaughter, defeathering, butchering, and preparation of poultry for cooking. There is no evidence that properly cooked poultry or poultry products can be a source of infection.
Countries located along migratory routes need to be vigilant for signs of disease in wild and domestic birds. Recent events make it likely that some migratory birds are now implicated in the direct spread of the H5N1 virus in its highly pathogenic form.[25]
To avoid any contact of poultry with wildlife birds all poultry farms must keep their poultry indoors.
In animals, avian influenza is most commonly transmitted through direct contact with wild birds, especially asymptomatic waterfowl, and contacts with infected poultry and poultry products. There are also common indirect routes, e.g. through contaminated clothing, footwear, vehicles and equipment, as well as contaminated feed, water, manure and litter. Insects, rodents, cats and dogs can also act as vectors and transmit the disease.[26]
In several countries in Asia, rural families keep small free-range flocks and up to 80% of poultry are raised at small-household village level. This poses a challenge for controlling outbreaks of highly pathogenic avian influenza (HPAI) in poultry.
Poultry and humans often share the same environment in Asia. Poultry are present in almost all villages and are generally marketed as live animals. In these conditions, the disease can spread quickly between the many small flocks.
The practice of home slaughtering means that human exposure to the virus can easily occur in affected areas.
Outbreaks in Hong Kong and the Neatherlands in 2003 could be controlled by culling of infected flocks, quarantine, bans on the movement of animals, and compensation schemes for affected farmers because the affected areas were characterised by industrial production conditions.


Avian Influenza and food safety

According to WHO, there is a recent concern over the possibility that the avian influenza in addition to direct contact with live infected animals could spread through contact with contaminated poultry products. To date there is no epidemiological information to suggest that the disease can be transmitted through contaminated food or that products shipped from affected areas have been source of infection in humans.
Reports indicate that in addition to chicken, pigs and ducks have also been infected. Infected chicken flocks rapidly develop symptoms and should be destroyed before having any possibility to enter the food-chain. Ducks have been reported to be asymptomatic carriers and duck products such as frozen duck meat could be contaminated with the H5N1 virus.
The further processing would inactivate the virus. In general, good hygiene practices during handling of raw poultry meat and usual recommended cooking practices for poultry products would lower any potential risk to insignificant levels.
Eggs from infected poultry could also be contaminated with the virus and therefore care should be taken in handling shell eggs or raw egg products.
Freezing and refrigeration does not substantially reduce the concentration or virulence of viruses on contaminated meat. Proper cooking kills such viruses. In general, WHO recommends that food s should be cooked to reach an internal temperature of 70° C.[26]

Nutraceuticals as preventatives of H5N1 virus infection [27][28]

Professor Edzard Ernst, professor of complimentary medicine at the University of Exeter, said in February 2006 that olive leaf extract, garlic, oregano oil, bee pollen, cayenne pepper, garlic colloidal silver, aloe vera, Echinacea, kimchi (Korean sauerkraut), cranberry juice, honeysuckle and green tea present no scientific evidence to support claims such as to protect against avian flu.

Dr. Damien Downing, president of the British Society for Ecological Medicine, and medical director of the Alliance for Natural Health called the statement of Professor Ernst irresponsible and a danger to public health. He pointed out the importance of zinc and vitamin C when it comes to fight infections being then essential for the immune system. However, less than ten per cent of adults in the UK have sufficient levels of zinc in their diet.

The point of view of Dr. Dowing was countered by Dr. Ron Cutler from the School of Biosciences at the University of East London saying that the H5N1 virus is said to stimulate the immune system, fillilng the lungs with blood causing death. Any supplement boosting the body's immune system would be of no help at that time.

New outbreak of avian flue in Bavaria, Germany

The H5N1 virus has been confirmed at a poultry farm at Wachenroth, Erlangen-Höchstadt in Erlangen, Bavaria, Germany. According to Ursula Huber from the German agricultural ministry, 160.000 animals were culled, and the farm was sealed off. About 400 geese had died on the 24.of August 2007. Farmers are ordered to keep poultry indoors.

The health officials advice the public not to eat food products containing raw eggs, as already 190 death were caused worldwide by the virus H5N1 since 2003. With this new outbreak in Germany heavy financial losses come over the poultry business.

Avian influenza in Brandenburg, near Berlin [29]

New cases of avian influenza by H5N1 virus were confirmed in various locations in Brandenburg,. in 27.12.2007, near Berlin. Health officials disposed a quarantine zone around the affected farms. All birds were culled. Cats and dogs should be kept indoor to avoid contact dead wild bird bearing H5N1 virus.

The European Union's Standing Committee on the Food Chain and Animal Health issued the following recommendations for areas where H5N1 has been confirmed in wild birds:

- Sick or dead cats and dogs should not be touched and the veterinary authorities should be informed, so that post-mortem examination and further testing can be performed.
- Contacts between domestic pets, particularly cats, and wild birds should be prevented, i.e. cats should be kept indoors and dogs should be kept on a leash or otherwise restrained, and kept under control by the owner.
- All pet owners are advised to stay alert to reports of H5N1 infections in either migratory waterfowl or domestic poultry in their local area and the possible need to quarantine dogs and cats accordingly.

The U.S. Department of Health and Human Services (HHS) is offering a guidebook for families and households to plan for infectious disease. HHS Secretary Michael Leavitt released Pandemic Influenza Planning: A Guide for Individuals and Families January 6. [30]

A specific vaccine for humans that is effective against avian influenza has not yet been approved. Based upon limited data, the Centers for Disease Control ave suggested that the anti-viral medication Oseltamavir (brand name-Tamiflu) may be effective in preventing or treating avian influenza.

Please see the State Department's publication "Meeting the Challenge of Bird Flu" for more background on the U.S. commitment, the science and response to bird flu. [31]

New outbreak2007 of H5N1 virus in UK

In UK a new outbreak of H5N1 virus avian flue was noted on the 27.01.07 and confirmed on the 03.02.07 in the English, province of Suffolk, Upper Holton in a farm for turkeys for meat production.

Three zones were declared around the Infected Premises to reduce the spread of disease. These are the Protection Zone (3km), the Surveillance Zone (10km) and a wider Restricted Zone, encompassing wider areas of Suffolk and Norfolk.

UK loses its status as "disease free" country (06-02-07) and Ireland, Russia, Hong Kong, South Africa, South Korea and Japan and India impose ban on UK poultry meat, live birds and hatching eggs. The chief veterinary officer in charge, Fred Landeg, confirmed that about 159,000 turkeys have been culled.

10.02.07: The H5N1 virus of the farm is identical to the virus of recent outbreaks in Hungary according to a statement on 10.02.2007 of the official veterinary officer in charge. The company has poultry farms and production sites all over UK Germany and Hungary and transports fresh meat from one side to another. The veterinary investigators believe that the virus was on this way imported from Hungary.

Influenza H5N1 virus confirmed in wild birds in Dorset [32]

According to UK Defra laboratory test has confirmed highly pathogenic H5N1 avian influenza in wild swans in Dorset. A 3km Control Area and a 10 km Monitoring Area has been established around the location.

UK, Poland, Hungary, Germany and the Czech Republic are European countries where bird flue outbreaks took place.

Still human death cases caused by H5N1 avian flue virus

[33]

Egypt

One teenage girl tested positive for the H5N1 avian flu died on April 10, 2007 at a hospital in Cairo despite Tamiflu medication. The total number of H5N1 deaths in Egypt are 14.

Nigeria

In the city of Lagos, Nigeria, 11 contact persons were tested for H5N1 virus, having symptoms of the disease in early April 2007. One women died on February after slaughtering a chicken without wearing gloves or a mask and probably spread the virus to their contacts.

Reported deaths due to H5N1 virus (WHO 11.04.2007) [34]

Azerbaijan 5
Cambodia 7
China 15
Egypt 14
Indonesia 63
Iraq 2
Laos 2
Nigeria 1
Thailand 17
Turkey 4
Viet Nam 42
Total 172

Preparedness plans for a global flu epidemic

The U.S. Department of Health and Human Services gives advices and preparedness plans for a global epidemic.
Please look at http://www.avianflu.gov/plan/individual/index.html

Intensive animal food production systems [35]

According to Food and Agriculture Organization of th United Nations (FAO), global animal food production is undergoing a major transformation that could lead to a higher risk of disease transmission from animals to humans.

The risk of disease transmission from animals to humans will increase in the future due to human and livestock population growth, dynamic changes in livestock production, the emergence of worldwide agro-food networks and a significant increase in the mobility of people and goods.

Excessive concentration of animals in large scale industrial production units should be avoided and adequate investments should be made in heightened biosecurity and improved disease monitoring to safeguard public health.

How humans can protect themelves from bird flu

A healthy lifestyle with plenty of exercise to keep immune levels high, making sure to wash hands regularly is recommended.
Avian flu virus strains are widely distributed within the bodies of diseased chickens and turkeys, as well as in sub-clinically infected species like ducks.

Chickens, for instance, have the highest viral load at the end of the incubation period, just before the bird becomes ill. The viruses are expelled from the body in the feces during the acute stage of the disease and may end up contaminating food and water. Human infections have generally resulted from direct and intensive contact with infected poultry.

Particularly high risk has been associated with slaughtering, defeathering, butchering or preparing sick birds for consumption, with exposure to infected droplets as well as feces being possible sources of infection.

A third of the cases reported in Vietnam had no direct exposure to poultry and the source of the infection remains unknown. Two confirmed cases have followed consumption of raw duck blood pudding. Another case may have been linked to swimming in a canal frequented by infected ducks. EFSA74

According to the French Food Standards Agency keeping birds indoors will not eliminate the risk of infection, since the virus could be carried in mud containing wild bird feces, or in feathers, litter or food. The agency calls for strict biosecurity measures on farms.

Avian influenza and industry

The current bird flu scenario should not cause panic and fear; instead it calls for rational and immediate action to fight the disease at its origin - that means in animals.

Pigs and poultry

Globally, pig and poultry production are the fastest growing and industrializing livestock sub-sectors. As a consequence, in the industrialized countries, the vast majority of chickens and turkeys are now produced in houses with 15 000 to 50 000 birds. This business is being introduced in Asia, South America and Africa.

Industrial pig and poultry production relies on a significant movement of live animals. In 2005, for example, nearly 25 million pigs, more than two million pigs per month, were traded internationally.

According to FAO the highly pathogenic H5N1 virus is currently of major global concern, however, the "silent" circulation of influenza A viruses (IAVs) in poultry and swine should also be closely monitored internationally. A number of IAVs are now fairly widespread in commercial poultry and to a lesser extent in pigs and could also lead to emergence of a human influenza pandemic.

FAO called upon meat producers to apply basic biosecurity measures. Production sites should not be built close to human settlements or wild bird populations; farms should be regularly cleaned and disinfected; the movements of staff and vehicles should be controlled and employees should be trained in biosecurity.


Swine Influenza A (H1N1) virus mutation is resistant to antiviral drugs [36]

The virus found in pigs infected humans. Now the subtype of the influenza virus which caused the death of 20 to 50 million people in 1918 can travel from person to person. [37]

In 2005 a virus laboratory regained the plasmid of the 1918 epidemic using samples of human corpses which had been buried in Arctic permafrost.

About 1000 are hospitalized in Mexico city and 18 already died. California report 6 cases of the new H1N1 virus which is resistant to Tamiflu antiviral drug. In California 6 persons and two in Texas were tested positive for H1N1.

Recommendations

CDC recommends:
There are everyday actions people can take to stay healthy
- Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
- Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hands cleaners are also effective.
- Avoid touching your eyes, nose or mouth. Germs spread that way.
Try to avoid close contact with sick people.
- Influenza is thought to spread mainly person-to-person through coughing or sneezing of infected people.
- If you get sick, CDC recommends that you stay home from work or school and limit contact with others to keep from infecting them.
Other effective measures to avoid infection
Avoid handshaking
Avoid kissing
Use surgical mask

Antiviral drugs resistance [38]


Oseltamivirn (Tamiflu)

Concern about H5N1 bird flu caused the development of the Tamiflu drug the new flu causing concern is a pig virus, of a family known as H1N1. The antiviral drug Tamiflu, also known as Oseltamivir blocks the H5N1 enzyme Neuraminidase, and was known to be efficient against influenza viruses A and B. The H1N1 mutated the expression of the enzyme and became resistant to these antiviral drugs. Health official advice, therefore, not to use Oseltamivir any more, or when, give it together with Amantadine (Relenza), which is an uncoating inhibitor.


Amantidine (Symmetrel)

In Europe infections with H1N1 are about 10% of flue cases, and H3N2-Viruses are more common. H3N2 viruses are resistant to Amantadine, but sensitive to Oseltamivir, which is also efficient against influenza B viruses.


Zanamivir [Relenza]

According to Patrick Hollstein 2009 there is no resistance of H1N1 to the second neuraminidase inhibitor Zanamivir (Relenza ) reported. It is useful against influenza viruse A and B.


Rimatidine (Flumadine)

It is active only against influenza A viruses.

Doubts on the effect on Tamiflu to treat swine flu [39]

Prof. Bernd Mühlbauer, director of the Institute of Pharmacology at the Clinical Centre Bremen, Germany calls for human studies on the effectiveness of Tamiflu before million of Euro are being spent to built a stock sufficient for 20 percent of the population, as demanded by the German National Pandemic Plan.

Up to date only laboratory studies were conducted to verify the effect of the drug on swine influenza virus. Mühlbauer says that other influenza drugs reduce flu only by the average of one day. He fears that the drug is prescribed too often in an irresponsible manner.

The German pharmacology expert says that the drug should be stocked only for risk patients, medical personal, police and fireman. Only such groups should receive prophylactic drugs in case of a pandemic.

H1N1 influenza may present atypical Symptoms [40]

According to Fatima S. Dawood the H1N1 virus causes common influenza signs of fever, cough, and sore throat, additional diarrhea and vomiting may also occur in one fourth of cases. The CDC recommends, therefore, to look after an association of signs of seasonal influenza and atypical gastrointestinal signs. A wide clinical spectrum similar to that seen among persons infected with earlier strains of swine-origin influenza viruses are reported.

Two groups of H1 virus have evolved from the 1918 pandemic influenza virus [41] [42]

The present H1 viruses is derived from Eurasian rather than North American swine flu lineages.

Other sporadic human influenza cases caused by triple-reassortant viruses occurred before the current outbreak and appeared to be transmitted from pigs to humans. CDC cautions that sporadic cases of triple-assortment influenza infections in humans who have had contact with pigs may be sentinels for a larger outbreak.

The 2 groups of viruses differ in their infective potential. They evolved from viruses from 1918 and have subsequently evolved. Dr. Robert Beshe says that infections are caused by remnants of the 1918 pandemic influenza virus.

In case of flu signs the CDC stresses to consider recent history of exposure to pigs, domesticated fowl, or wild birds, especially when human flu viruses are not in circulation in the community.

WHO Increases Pandemic Alert Level to Phase 6 [43] [44]

On 11 June 2009 The World Health Organisation's director-general Dr. Margaret Chan has officially declared the swine flu to have entered the pandemic phase 6.

Phase 6

the pandemic phase, is characterized by community level outbreaks in at least one other country in a different WHO region. Designation of this phase will indicate that a global pandemic is under way.

Dr. Chan pointed to the fact that actually the swine flu pandemic coexists with the H5N1 avian flu in phase 3 pandemic alert status. This is considered to be an extremely unusual situation. She pointed out that pregnant women are at increased risk for complications, and the virus preferentially infects younger age groups, under age 25 years.

Although there have not been large numbers of severe cases in USA so far, severity may increase toward fall. H1N1 immunization campaign should therefore start in late September.

Swine Flu virus A/1H1N is a super flu that consists of 3 known swine flu strains, 3 known bird flu strains and a human flu virus. The combination of these strains makes the A/1H1N Swine Flu an unusual strain of the flu with unknown outcomes.

If you had contact with persons which may be suffering from this new hybrid strain of Swine Flu, in special travellers from USA and Mexico, seek immediate medical advice.

WHO recommends a measured fever over 100, along with either cough or sore throat an also has an underlying condition, whether you have asthma, diabetes, or are pregnant, or an infant under the age of 2, see your doctor right away to see if you should be treated for influenza with antiviral medication.

Swine flu, a seasonal flu, CDC says school closing is rarely indicated [45]

CDC Director Thomas R. Frieden, MD reported that closure of schools is rarely indicated, even if flu is in the school.

Health and Human Services Secretary Kathleen Sebelius pointed out that the disease caused by swine flu is not more severe than disease caused by seasonal flu.

The new CDC Swine Flu Rules for Schools

CDC recommends not closing schools during a wave of pandemic swine flu, and follow the advices:

Stay home when sick

If you've had the flu, don't go back to school until 24 hours after your fever goes away.

Separate ill students and staff

Students and staff who appear ill should be sent to a room separate from others until they can be sent home. They should wear surgical masks if possible; those that care for them should wear masks, too.

Wash hands, observe cough/sneeze etiquette

Frequent and thorough hand washing will be more important than ever. So will covering each cough or sneeze with a disposable tissue (or shirtsleeve or elbow if tissues aren't available).

Routine cleaning

School staff should clean areas that students and staff touch often. Use normal cleaners; bleach and special cleansers aren't necessary.

Early treatment of at-risk students and staff

People at high risk of severe swine flu disease - for example, those who are pregnant, have asthma or diabetes, neuromuscular diseases, or immune deficiency - should see a health provider as soon as they become ill. Early antiviral treatment is very important for them.
If swine flu becomes more severe:

Active screening

Students and staff should be checked for fever and other flu symptoms every morning; those with these symptoms should be sent home. Throughout the day, students and staff should be on the lookout for people who appear ill.

High-risk students/staff should stay home

Students and staff with conditions that put them at high risk of severe flu disease - such as pregnancy, chronic asthma, or heart disease - should stay home from school "when a lot of flu is circulating in the community." Schools should immediately start planning for the continued education of such students.

Students with ill family members should stay home

Students should stay home for five days starting from the first day their household member got sick. This is the time they are most likely to get sick themselves.

If sick, stay home longer

Stay home for at least seven days even if you feel better before then. If you still feel ill after seven days, stay home for 24 hours after your symptoms finally go away.

Consider school closure

If it's deemed necessary to close a school, the school should remain closed for five to seven calendar days and then consider whether to reopen.

Travel restrictions immediately needed

The WHO says that it continues to put no restrictions on travel. The reason of WHO hesitation to impose travel restrictions may result from pressure of USA who fears economic losses. However, the pandemic spreads worldwide by travellers coming from USA and Mexico. WHO must undergo criticism for the lapse of not imposing travel restrictions. There are worldwide about 300.000 cases of swine flu human infection known of which 13.000 in USA.

Facemasks are not effective protection from H1N1 virus [46]

The FDAlabeled as surgical, laser, isolation, dental or medical procedure masks are a loose-fitting and do not protect against viral infections. A facemask is effective in blocking large-particle and droplets but is ineffective to block very small particles emitted by coughs or sneezes.

N95 Respirators for Use by the Public

An N95 respirator is a device which achieves a very close facial fit and blocks at least 95% of very small test particles. However, they are not appropriate for children or people with facial hair.
FDA has cleared the following N95 respirators for use by the general public in public health medical emergencies:

Fitted N95 Respirators Recommended to Protect Healthcare Workers

N95 respirators cleared by FDA for use in the healthcare setting are called surgical N95 respirators

The Institute of Medicine IOM recommends the use of fitted N95 respirators for healthcare Workers to protect against H1N1 infection [47]

A report of the IOM stresses that filtration and fit of medical masks are insufficient to to avoid small particles to overcome the barrier of the mask and inadequate fit do not offer an effective protection against airborne transmission. The IOM recommends therefore, the use of N95 respirators which filter out at least 95% of particles 0.3 µm or larger blocking the influenza virus.

Face masks and N95 respirators are not reusable [48]

The N95 respirator is the least expensive and the most widely available respirator for protecting healthcare workers and the public against airborne infection. However, disposable N95 respirators cannot be effectively cleaned or disinfected and should therefore be discarded after each use.

Origin of the swine flu virus described [49]

Andrew Rambaut and colleagues 2009 showed that the H1N1 virus is a mixture of other viruses that had been circulating in pigs and includes human and avian-like genetic sequences. The initial transmission to humans occurred several months before recognition of the outbreak.

The authors say that movement of live pigs between Eurasia and North America seems to have facilitated the mixing of diverse swine influenza viruses and the lack of systematic swine surveillance allowed for the undetected evolution for many years.

Analysing the molecular structure of the virus, the authors dated their appearance between 9.2 and 17.2 years ago and remained undetected for about a decade. The pork industry protested against the use of the term "swine flu" and exerted pressure on the WHO to use the generic designation of "influenza A(H1N1)" fearing pork prices to be affected.

Influenza threat of the North American swine [50]

Gerardo Nava and colleagues 2009 reported that their genetic analysis also pointed to North American swine as a potential source of the new virus. The researchers call for a systemic surveillance system which integrates phylogenetic information of influenza viruses circulating in humans and livestock.

Meanwhile entire poultry flocks are slaughtered to control outbreaks of avian influenza, no action is take in face of outbreaks of swine flu. Pork farmers wait out outbreaks among their flocks because the infection rarely kills the animals. According to Nava and colleagues this may permit the virus to recombine in the pig and elaborate new sequences, new genes.

Nava and colleagues said that officials focused on avian flu and ignored the new threat coming from pigs and the people who work with them.

The authors point to the fact that the United States invested 3.8 billion dollars to prevent and contain the foreign threat of Asian avian flu, neglecting the influenza threat that the North American swine population presents. Protecting itself from foreign avian flu USA neglected to protect the world from the swine flu whose origin is now being tracked to be the North American swine.

Collecting specimen for H1N1 swine influenza testing [51]

Nasopharyngeal swab as respiratory specimes, sera for cases or contacts of cases with confirmed swine influenza.

Specimens should be collected within the first 24-72 hours of onset of symptoms and no later than 5 days after onset of symptoms. The specimens should be kept refrigerated at 4° and sent on cold packs if they can be received by the laboratory within five days of the date collected. If samples cannot be received by the laboratory within five days, they should be frozen at -70° or below and shipped on dry ice.

Laboratory testing

Throat smear taken by health officials are sent to a lab performing the tests:
1 - The US Flu Rapid Antigen testing: This test is not specific. Its sensitivity is unknown. A negative result does not exclude a diagnosis of swine influenza A and should be submitted to PCR and subtyping.
2 - The CDC under the Emergency Use Authorization (EUA) procedure authorized diagnostic tests called "diagnostica reverse-transcriptase polymerase chain reaction (RT-PCR) swine influenza panel", the "rapid influenza antigen" and the "immunofluroscence". All three can detect the new swine influenza virus, but they only identify probable cases because they cannot distinguish between seasonal influenza A and swine influenza, which is a subtype of A.
3 - The RT-PCR can conclusively confirm a case of swine influenza.
4 - Culture of the virus in cell cultures and chicken eggs. This takes much time. Active infection with swine influenza can only be confirmed by polymerase chain reaction (PCR) assays, including subtyping and further characterization by other special PCR assays

Laboratory safety precautions

Rapid antigen testing or PCR) can be performed under BSL-2 conditions. All sample manipulations should be done inside a biosafety cabinet. (BSC). Viral isolation on clinical specimens from patients who are suspected cases of swine influenza A (H1N1) virus infection should be performed in a BSL2 laboratory with BSL3 practices (enhanced BSL2 conditions).

Safety precautions during specimen collection

Personnel collecting clinical specimens should wear a fit-tested N95 respirator, goggles, disposable gown, and disposable gloves. When completed, place all personal protective equipment in a biohazard bag for appropriate disposal. Wash hands thoroughly with soap and water or alcohol-based hand gel.

Egypt culls swines to prevent swine influenza pandemic [52]

The Health Minister of Egypt ordered the culling of Egypt's 400,000 pigs. Pigs are seen as unclean, Haram by muslims.

The culling should help to protect against swine flu. Egypt had been hit by the last H5N1 avian influenza and fears another flu pandemic. There are no infections of swine flu reported yet, a pandemic flu strain could, however, spread quickly through the heavy crowded region. A member of the Cabinet called the conditions of the swine farms in Egypt as unhealthy, being a hazard in themselves, even without the swine flu.

A compensation of £120 per pig were offered, but the farmers doubt that the money will ever be payed and they claim the loss of their livelihood. They say that the pigs are feeding from 6,000 tonnes of organic rubbish produced in he region every day and they do not know how the food scraps should be handled otherwise.

The UN food experts say pork meat is safe

The UN food experts call the culling decision a mistake, stressing that the newly mutated H1N1 virus is not found in pigs. The animals can be the vessels for the "genetic reassortment" that produces new strains, but pork meat is safe to eat, because it must be cooked anyhow.

Canadian swine herd infected with H1N1 by farme worker returning from Mexico [53]

Pigs in Alberta were infected with H1N1 by a farm worker who fell ill after returning from Mexico. Pigs can be infected by flu virus from human and avian virus. The pig is able to mix its own flu virus with the human and the avian type. The result is a dangerous pandemic form of influenza.

Import restrictions on pork

Russia and China imposed an import ban of pork from USA, Canada and Mexico.

German IT company "ExploSYS" developed an Influenza-Pandemic-Planning-Simulator InfluSim [54] [55] [56]

The epidemiologist Prof Dr. Martin Eichner, from the German city Tübingen, together with the mathematician Markus Schwehm developed an "Influenza-Pandemic-Planning-Simulator InfluSim" which will support decision makers at airports, medical centres, health departments and governments to find the best measures to counter pandemics.

The simulator received input from the German Robert Koch Virus institute and will be distributed by ExploSYS. The developers say that simulation shows that even closing the borders to a country with disease cases, the pandemic will get through, because no border can be absolutely leak proof. For such events the pandemic simulator shows where the first cases are expected to turn up.

Influenza A H1N1 avian flu virus continues to spread [57] [58]

The WHO on its report of May 4, 2009 sees the virus moving south, but no community-level transmission is being reported right now.

WHO pandemic alert level is being maintained at phase 5. An increase to phase 6 will take place when community-level transmission is occurring in more than 1 WHO region. Currently, such outbreaks are taking place only in North America.

The spectrum of illness varies from very mild to fatal cases occurring in young, healthy people infected by the influenza viruis H1N1. Severe pneumonia, 40% to 50% of patients developing diarrhoea are some signs of the disease.

WHO says that the incubation of a regular influenza is about 5 days. With H1N1 there is uncertainty about whether it is 6, 7, or 8 days. Dr. Besser from the CDC expects all states to have confirmed cases, ongoing hospitalizations and additional deaths.

The big H1N1 hype of Roche

Now that tension concerning swine flu in media revives, some conclusions become evident. Marketing department of leading pharmaceutical corporations performed a spectacular job heating up media and politics. Nobody dared to argue about the necessity of a vaccine and stockpiles of Tamiflu.

CNBC on his morning business ticker of 23.07.2009 reported a net profit of 4.05 Billion Swiss francs at Swiss drugmaker Roche on account of H1N1 vaccine. [59]

Global sales of the antiinfluenza medicine Tamiflu (oseltamivir) rose 203% to 1.0 billion Swiss francs in the first half-year. Sales to governments and corporations for pandemic stockpiling amounted to 653 million francs (609 million francs in the second quarter of 2009 compared with 49 million francs in the second quarter of 2008).

Roche, working with the World Health Organization (WHO) and national governments, started in May 2009 to supply Mexico and 71 other countries with the stocks of Tamiflu, and by the start of 2010 Roche will be able to supply up to 400 million packs annually. Oseltamivir will also be produced for China, India. [60]

Germany's health ministers on 21.07.2009 agreed on a plan to order some 50 million units of flu vaccine units. That's enough to immunize 25 million people against the H1N1 swine flu - a person has to be injected twice in order for the vaccine to be effectiveThe vaccines will provide protection for 30 percent of the German population.

In Germany 727 cases of swine flu have been reported, none were fatal. Authorities fear a mutation of the swine flu virus, could prove deadly. The H1N1 hype continues, boosted by governments and the WHO which warned that the spread of swine flu was unstoppable [61].

Mutation

Flu viruses mutate continuously. That is why vaccination of "common" cold is considered ineffective. Brazilian Adolfo Lutz Bacteriological Institute identified a new strain of the H1N1 called A/São Paulo/1454/H1N1 and compared it with samples of the A(H1N1) swine flu from California. According to Terezinha Maria de Paiva (June 16, 2009) the mutation comprised alterations in the Hemagglutinin protein which allows the virus to infect new hosts. However, it was not yet known whether the new strain was more aggressive than the current A(H1N1) virus. [62]

Severity is of no concern, says WHO [63]

At this time, WHO considers the overall severity of the influenza pandemic to be moderate. This assessment is based on scientific evidence available to WHO, as well as input from its Member States on the pandemic's impact on their health systems, and their social and economic functioning.
The moderate assessment reflects that:

Vaccination for H1N1 unnecessary

Looking at the costs and the results, it immediately becomes clear that there were rare global cases of death. Comparing with death tolls of other contagious diseases such as tuberculosis, malaria, viral hepatitis, early summer meningocephalitis and others, H1N1 is of no concern. Note hat Germany having diagnosed more than 3.000 cases had no even one single fatal case. Swine flu is thus a mild, often asymptomatic disease. The risk of adverse effects of vaccination is high, compared with flu risk. Contact with the swine flu trains the immune system building up barriers against flu viruses.

WHO and German health officials in an last effort to hide the wrong decision stress that mutation of the actual mild H1N1 virus may mutate to a more virulent variant. The pharmaceutical industry awaits hopefully this hype to be spread by the media.

Contagious period of swine influenza H1N1 [64]

De Serres and colleagues 2010 report that, according to their data, persons infected with pandemic (H1N1) 2009 virus, a minimum of 8% of outpatients shed replicating virus on day 8. The authors conclude that self-isolation only until fever abates appears insufficient to limit transmission. They call for a self-isolation at the household, for a week and caution that some patients may shed infectious virus for a longer period.

Some studies with seasonal influenza state that virus shedding after day 7 is rare, but clinical studies have shown that shedding may persist beyond that period in some populations, such as elderly persons, immunocompromised patients, and children.

Contagiousness

According to the authors, contagiousness depends on viral load and depends on the spread of droplets (such as coughing, rhinorrea, or sneezing), the number and proximity of contacts between a case-patient and a susceptible person.

CDC recommend outpatients to extend the reclusion 1 day after end of fever

CDC recommends that people with influenza-like illness remain at home until at least 24 hours after they are free of fever (37.8°). [65]

Duration of isolation precautions for hospitalized patients

CDC says that the recommended duration of isolation precautions for hospitalized patients is longer than that recommended for other populations because duration of virus shedding is likely to be longer than for outpatients with milder illness. De Serres, however, calls to extend the precautionary measures of hospitalized patients also to outpatients.

Isolation precautions for patients who have influenza symptoms should be continued for the 7 days after illness onset or until 24 hours after the resolution of fever and respiratory symptoms, whichever is longer, while a patient is in a healthcare facility.

Because some patients with influenza may not have fever but may be shedding influenza virus, patients with any respiratory symptoms should follow hand and respiratory hygiene recommendations. [66]
With pandemic (H1N1) 2009, fever generally persists 1-4 days and may be absent in 6%-11% of patients. In our study, of the 32 pH1N1 PCR-positive household members who had been symptomatic for less than 7 days, 78% had fever at any time since onset of their illness, but only 34% were still febrile on the day they tested positive. Nonetheless, 97% of specimens obtained from these patients were positive by cell culture.

Before policy implications can directly follow from these findings, the association of self-isolation with substantial social impact needs to be carefully weighed against the possible benefits of reducing community transmission. In the general population, a 1-week self-isolation period seems more likely to prevent transmission than does isolation until fever has resolved. However, given that 8%-13% of patients may still shed infectious virus on day 8, longer periods of self-isolation for persons expected to come into contact with vulnerable persons (e.g., pregnant women, newborns, or immunocompromised persons) also may be prudent.

Infectious viral shedding

Ling and colleagues 2010 write that virus shedding in pandemic (H1N1) 2009-infected patients in Singapore, treated with oseltamivir, were still PCR positive by 37% of the patients on day 7 of their illness and 9% on day 10. The authors also note that oseltamivir, prescribed during the first 3 days of illness, shortened the duration of viral shedding. [67]

According to Li and colleagues 2010, oral oseltamivir medication initiated 2 day or earlier, suppresses infectious viral load of nasopharyngeal aspirate of pandemic 2009 influenza A(H1N1) more effectively compared with patients with an onset of medication after 2 days, and was significantly lower, compared with nontreated. No viral load was determined at day 6 of medication. [68]

Highest viral load in respiratory samples, stool and urine occurred on the day of onset of symptoms. Eight days after onset of symptoms the RT-PCR 8 and after 5 days the were negative with only one exception. Younger age was associated with prolonged respiratory tract and stool shedding was observed in younger people. [69]

Quick test for H1N1 [70]

Louie and colleagues 2010 say that diagnose influenza at the point of care, using commercial rapid enzyme immunoassay, are unable to differentiate between influenza A virus subtypes and the sensitivity varies between 40% and less, up to 90%, compared with PCR and culture methods. The authors compared the QuickVue Influenza test (Quidel Corp., San Diego, CA, USA) with PCR and culture methods, and found that the test had suboptimal sensitivity and specificity for the detection of pandemic (H1N1) 2009. Their results should be confirmed with PCR. The authors call for the development of more accurate rapid tests.

H1N1 now in the post-pandemic period (Disease activity at seasonal levels) [71]

10 August 2010 - WHO Director-General, Dr Margaret Chan announced that the H1N1 influenza virus has moved into the post-pandemic period. However, localized outbreaks of various magnitudes are likely to continue. WHO says that the world is no longer in phase 6 of influenza pandemic alert. The new H1N1 virus has largely run its course.

The WHO recommends monitoring for unusual events, such as clusters of severe respiratory illness or death, and monitoring the H1N1 2009 virus for important genetic, antigenic or functional changes, such as antiviral drug sensitivity. [72]

Costs of exaggerated panic of advising instituts in Germany [73]

The Rober Koch Institute was responsible for advices to the Health Departments regarding vaccination of German population. The institute spread panic informations, leading to the order of 34 Million H1N1 vaccines. Only 4,17 Mio units were used following a restricted number of illness and mild disease. 336 Million EURO of unused vaccines must be paid by taxpayers.

The blue ear disease [74]

Chinese officials say million pigs are dying in China killed by the epidemic on Porcine Reproductive and Respiratory Syndrome (PRRS), or blue ear disease , which is caused by a virus in the arterivirus family. This disease is known as post-weaning multisystemic wasting syndrome PMWS in Europe, and as the porcine circovirus associated disease PCVAD in USA.

It is a very common pig disease known for many years in Europe and USA in the mid 80s, from were it spread to other countries, such as to the Cape. China is being seriously hit by the disease, because pork is a staple food and meat is lacking on the markets and the government wants to release frozen stocks. [75]

The mortality is known to be up to 50% caused by the porcine circovirus type 2 (PCV-2), but has declined now to 1-2% in the nursery due to hygiene strategy and the porcine circovirus type 2 vaccine, but it is still up to 9% in finisher.

Human infectivity of blue ear disease [76]

According to Albert Osterhaus, a virology expert at the Erasmus University Medical Centre in Rotterdam, an international centre for blue ear disease, there are no indications that spread to humans can happen. Many viral infections that do occur in certain animal species are restricted to that particular species. A mutation to a variety which could be infectious to human, so as feared about the H2N5 virus of avian influenza, however, is highly unlikely.

Symptomatic

The virus causes still-births, fever, loss of appetite, diarrhoea, redness of the skin and mortality rates of up to 50 percent on some farms.

The ears of affected pigs turn blue. The virus invades and multiplies in the white blood cells which die later on in the lung tissue of the pigs. Up to 40% of the macrophages are destroyed reducing the defence mechanism and allows bacteria and other viruses to proliferate. The virus mutates quickly turning the production of vaccines difficult, but vaccination in Guangdong will start soon.

Rules for pig slaughterhouses in China

According to China's Ministry of Commerce the draft rules for pig slaughterhouses demands for a slaughterhouse to be licensed and approved by local governments and environmental bureaux, and must be located away from drinking water supplies, residential districts and public areas, the said on its Web site.

Transmission

Direct pig to pig transfer is not common; the transmitting agent is Hematopinus suis, the swine louse. The diagnosis is the Virus isolation The control of the disease is the elimination of lice and hygiene measures.

Chinese officials believe that carcasses thrown into rivers may have been responsible for the spread of the disease to the surrounding areas. Infected pigs were raised by individual rural farmers applying poor hygiene measures rather than industrialized pig farms.

Endemic areas include Africa (South of the Sahara), Spain, and Portugal. The outbreaks in the Dominican Republic, Haiti, and Cuba have beenn reported. In China the desease appeared in the mid-90s, and actually in the Cape Flats.

The blue ear disease virus not to be compared with the avian flue H5N1 and H7N1 virus [77]

Despite the economical impact, the blue ear virus does not menace mankind so as the H5N1 virus of the avian influenza does. China reports a new case of human infection with the H5N1 virus which was confirmed on the 30.05.2007. There had been no contact with sick birds prior to becoming unwell. Close contacts have been placed under medical observation and all remain well. Of the 25 cases confirmed to date in China, 15 have been fatal. In UK two human infections with the less deadly variant of H7N1 were reported.

Evolution of drug resistance in H5N1 avian flue [78]

Governments and organizations stockpile antiviral drugs such as oseltamivir (Tamiflu) to be prepared to control a possible influenza A H5N1 pandemic. Hill and colleagues 2008, however, warn that lineages of H5N1 are becoming resistant to adamantane derivatives, and a few lineages are resistant to oseltamivir.

The authors stress that the rise of resistance to adamantanes, including the nonprescription drugs amantadine and rimantadane, is linked to Chinese farmers adding the drugs to chicken feed as a flu preventative. If Tamiflu is ever used in the manner of adamantanes, similar drug resistance may evolve.

According to the study, H5N1 drug resistance to adamantanes arose through novel genetic mutations rather than an exchange of RNA segments within cells, a process known as re-assortment.

The authors developed phylogenetic methods, which, added to molecular evolutionary analyses, and geographic visualization using Google Earth, provided a framework for analysis of globally distributed genomic data that can be used to monitor the evolution of drug resistance.

China increases blue-ear vaccine production in 2008

According to Jia Youling, China's chief veterinary officer blue-ear pig disease also known as Porcine Reproductive and Respiratory Syndrome. has been brought under "preliminary control" through vaccinations and mass culls of infected pigs. In 2007 the disease had infected 257,000 pigs in 26 Chinese provinces, of which 68,000 died and 175,000 were destroyed. The highly pathogenic disease can be fatal for pigs, but the vaccinated pigs will no longer be infected by the disease. [79]

The Harbin Veterinary Research Institute has recently donated blue-ear disease vaccines for 800,000 pigs to five snow-hit provinces. The Institute increased its production of the vaccine in a bid to prevent the potential outbreak after the recent blizzard since spring is the season of a high occurrence in the blue-ear disease.

Blue-ear disease was first discovered in the United States in 1987 and spread to China in mid 1990s. China first spotted a more virulent form of the pig disease in the summer of 2006 and identified it as a mutated highly pathogenic strain in January of 2007. [80]


Norovirus

Norovirus should replace the designation "flu-like", "Norwalk-like","Norwalk- and Norwalklike viruses (Caliciviruses)", "bug".
Noroviruses are the most common viral agents of acute gastroenteritis in humans. Many studies on the epidemiological and genetic characteristics of Noroviruses outbreaks point to their importance in food safety. Rapid analytical methods were developed to identify the source of epidemics.


Norwalk- and Norwalklike gastroenteritis virus

are leading causes of foodborn diseases:Norwalk virus is part of a family which is not well defined It causes stomach and intestinal illness. It was first identified in 1972 in the city of Norwalk (Ohio). The group of these viruses are recently called Noroviruses. They are included in the genus Norovirus, family Caliciviridae. They are single stranded RNA, nonenveloped.
They spread by person-to-person contact from the stool of infected persons and its symptoms are vomiting and diarrhoea.Special care is needed to avoid spreading of the disease such as:
Avoid food or water which has been contaminated by stool from infected persons, raw shellfish, oysters, clams, ice, eggs, salads and other food contaminated by sick food handlers or water which has been contaminated by sewage of cities or disposals of boats.
Incubation is 1 to 2 days. Illness is not severe, but rehydration may be necessary. Recovery in 2 to 3 days. People with the virus are contagious skin to skin for 3 days after symptoms have disappeared. The stool remains infectious for 2 to 3 weeks after symptoms are gone. Strict handwasching and use of disinfectants are very important to avoid spreading of the virus.
People can be reinfected and have the disease several times in life because there are many strains and a strong mutagenic activity.
Food should be served in restaurants authorised persons only instead of self-serving service.
Hotels should carefully clean bed clothes and pillow cases. Refrigerators and icemachines should be thawed and cleaned periodically. As disinfectant chlorine water solution should be used.

Viral gastroenteritis outbreaks caused by caliciviruses have been associated with eating contaminated shellfish, particularly oysters (Crassostrea virginica), implicating sewage from oyster harvesting vessels as the probable cause of contaminated oysters.

Special measures

Special care is needed to avoid spreading of the disease.


Norovirus in oysters

If shellfish such as fresh oysters infected with norovirus are eaten, acute gasterointestitis may occur. Vomiting, stomach ache, diarrhoea and fever may result.

Available measures to fight Norovirus in oysters is to provide sterile water and use chlorine-based germicides. However, sterile cultivation is costly and the Norovirus is resistant to chlorine-based germicide and sterilising alcohol. The use of high chlorine concentrations will make shellfish unpalatable.

Researches made by IEMT/AIST with micro-bubbles which are ultra-fine gas water bubbles (less than 50 micrometers in size) containing low concentration ozone to inactivate norovirus in live oyster under cultivation as well as unshelled oysters. These micro-bubbels are concentrated oxygen and 2 per cent ozone.
As the bubbles are suspended in water, the bubble size shrinks spontaneously to the level of nanometer inactivating the virus.
The oxygen/ozone micro-bubbles also suppress legionella bacteriain a circulating bath system as well as carp herpes virus.

Norovirus GII.4 leading global cause of viral gastroenteris [81]

According to Said, Perl and Sears 2008 the Noroviruses are a leading global cause of viral gastroenteritis and a major contributor to food-borne illness. According to the authors the GII.4 strain of the virus dominates in epidemics by antigenic drift evading thus the immune system.

Norovirus NoV frequent agent of gastroenteritis in an older population [82]

Rosenthal and colleagues 2010 assessing outbreaks infections in an older population found that 70% were caused by Noroviruses, with a case-fatality rate of 0.5%. GII.4 strains accounted for 84% of Noroviruses outbreaks and had a mean duration of 33 hours versus 24 hours of non-GII.4 infections.

GAP, GMP and HACCP improves microbiological safety of ready to eat vegetables [83]

De Giusti and colleagues 2010 report that GAP, GMP and HACCP improves the microbiological safety of ready to eat vegetables compared with different preventive strategies, such as use of chlorine disinfection at a second washing step, or using a physical microbial stabilization. The aerobic mesophilic count and Escherichia coli were quantified, and the presence of Salmonella spp, Listeria monocytogenes, E. coli O157:H7, hepatitis A virus and Norovirus were determined. The authors found that GAP, GMP and HACCP presented better microbiological quality than those processed with chemical or physical stabilization.

Water purification systems are unable to remove Norovirus from bivalve moluscs [84]

The efficacy of the water depuration systems in the presence of Norovirus contamination of bivalve moluscs. Mussels, Manila clam and Pacific oyster were examined by reverse transcriptase-polymerase chain reaction before and after depuration. Viral RNA was detected non-depurated samples as well in depurated samples indicating that the purifying systems in place were not able to remove Norovirus contamination from the live bivalve molluscs, write Savini and colleagues 2009.

Removal of Norovirus during a coagulation-ceramic microfiltration of drinking water [85]

Shirasaki and colleagues 2010 assessed the removal performance as particles during a coagulation-ceramic microfiltration process using recombinant NV virus-like particles (rNV-VLPs), and the bacteriophages Qbeta and MS2, similar to Noroviruses. More than 4-log removal of rNV-VLPs with a 1.08 mg-Al/L dose of polyaluminium chloride in the coagulation-ceramic MF process was found . The removal ratios of Qbeta and MS2 were smaller than the ratio of rNV-VLPs. The authors concluded that both bacteriophages are appropriate surrogates for native Noroviruses in the coagulation-ceramic MF process. They suggest the use of Qbeta as surrogate.

Review of Calicivirus studies [86]

Catpally and colleagues reviewed the current studies of Noroviruses which had been hampered by the lack of animal model and tissue culture system. The authors report that recent advances in protein expression systems and the development of a mouse norovirus animal model have brought a rapid growing knowledge about these viruses.

New Porcine Calicivirus in US Swine [87]

Wang and colleagues 2011 report that new St-Valerien-like porcine caliciviruses are prevalent in up to 80% in finisher pigs in North Carolina. One strain, NC-WGP93C, shares over 89 genomic nucleotide identity with Canadian strains. The authors could not say whether these strains are pathogenic for animals or humans or may affect food safety.

The caliciviruses have been found in humans, cattle, pigs, cats, chickens, reptiles, dolphins and amphibians.Viruses in the family Caliciviridae are nonenveloped, polyadenylated, single-stranded, positive-sense RNA viruses with 5 genera (Norovirus, Sapovirus, Vesivirus, Lagovirus, and Nebovirus). The nonhuman primate Tulane virus and the porcine St-Valerien-like viruses, may become a new genera in the Caliciviridae family.

St-Valerien-like viruses have been detected in Canada, the United States, and Italy. In order to support the classification of St-Valerien-like viruses as a member of Casliciviridae it is important to demonstrate the presence of the virus in other regions and determine the genetic differences between strains. St-Valerien-like viruses are close to Tulane virus and human noroviruses, and more data may may help to clear if an interspecies transmission may take place, and find the best way to control the spread of the new viruses.

Wastewater and crop contamination by Norovirus and Ascaris lumbricoides [88]

Mara and Sleigh 2010 estimate norovirus and Ascaris infection risks to urban farmers in developing countries using wastwater for crop irrigation. To achieve a tolerable disease burden of 1 percent of the diarrhoeal disease a norovirus reduction of 1-2 log units and an Ascaris egg reduction to 10-100 eggs per litre are required. The authors stress that such reductions are easily achieved by minimal wastewater. A sequential batch-fed three tank/pond system are being suggested, in addition to education and regular deworming in farming regions.

The authors reminds that reductions of 4-6 log units can be achieved using settling basins (1-log unit), pathogen die-off (1-2 log units), produce washing in cold water (1 log unit) and produce disinfection (3 log units). [89]

Small Round Structured Viruses (SRSVs) [90]

SRSV infections are generaly short-lived illness, sometimes referred to as winter vomiting disease, which rarely need medication, however, they are the commonest cause of epidemic viral gastroenteritis. There was little known about these viruses before 1990 when the first sequencing of their DNA was reported. SRSVs infection causes projectile vomiting and short and less severe diarrhoea as noted with Norwalk virus. Headache and fever may occur in some patients.

Transmission: Transmission occur by person-to-person contact, food-borne associated with restaurants and receptions, outbreaks associated with potable water were reported in the USA. Water as source of an SRSV sudden outbreak should always be considered. Actual techniques are insufficiently sensitive to detect SRSV in water. Environmental and epidemiological investigations, based on examination of faeces of diseased must be used to determine the source.

Food-borne outbreaks of SRSVs: Bivalve molluscs (oysters, cockles and mussels) are the only type of food implicated in such outbreaks. Shellfish beds are often located in estuarine waters polluted with human sewage. Bivalve molluscs are filter feeders and concentrate low number of viruses of the sea water. Depuration process applied to oysters is effective in removing bacterial pathogens, but has almost no effect on these viruses.

A poor correlation of levels of bacterial indicator organisms and viral contamination is being reported. Efforts are being undertaken to replace the inefficient depuration by re-laying in biologically cleaner water before cleansing, to do so, the EU suggests a period of eight weeks for some areas and shellfish beds should be classified to use less hazardous locations.

Contamination from food handles: Food may be contaminated by an infected food handle. SRSVs are destroyed above 60° . Known outbreaks are related to eating shellfish raw or not cooked after handling. An infected food handler sheds SRSVs few hours before onset of illness and continues two to three days. Incubation time is 24-72 hours. [91]

Diagnostic detection systems using RT-PCR are available to determine the importance of SRSVs and investigate the point source outbreaks of non-bacterial gastroenteritis.

Rapid Concentration and Detection of Enteric Viruses [92]

Butot, Putallaz and Sánchez 2006 developed a method to detect enteric viruses such as hepatitis A virus, norovirus and rotavirus from berries, vegetables and frozen products.

The viruses were extracted from the food surface by a direct elution method in a glycine-Tris (pH 9.5) buffer containing 1% beef extract and concentrated by ultrafiltration. PCR inhibitors were eliminated with pectinase treatment. The concentration method was combined with real-time reverse transcription-PCR (RT-PCR) using specific primers. The authors write that the procedure is suitable to detect and quantify enteric viruses within 6 h and can be applied for surveillance of enteric viruses in fresh and frozen products.

Control for losses of target virus [93]

To control for losses of target virus during concentration and extraction, samples are spiked prior to processing with a define amount of a process control virus. The Mengo virus strain VMCO in known concentration is used in the CEERAM Kit. Mengo virus strain MC0 is a recombinant virus, non pathogenic and culturable. This virus has structural and physico-chemical properties close to those of hepatitis A virus. It has resistance properties in environment close to those of targeted viruses

By adding a known quantity of mengo virus in each sample prior any processing, it is possible to define an extraction efficiency for each sample after amplification by real time RT-PCR and comparison with an equal quantity of Mengo virus purified from cell culture.

Hepatitis A virus [93]

Incubation of hepatitis A virus is around thirty days. Clinical signs of the infection vary from asymptomatic case in children younger than 6 years old to acute hepatitis. Fecal-oral parental, sexual, salivary or urinary transmissions are reported. There is no specific curative treatment but a vaccine is available. Hepatitis A virus can resist to different physical and chemical treatments, and can survive in different kind of environment for a long period.

The diagnostic by cellular culture or ELISA is not adapted to the detection of Hepatitis A virus in environmental or food samples. Molecular techniques (real time RT-PCR) are the methods of choice for Hepatitis A detection after extraction and viral RNA purification from the sample.

Purification of Norovirus RNA from human stool samples [94]

Magnetic-particle technology are used for rapid purification of nucleic acids. The magnetic-particle technology, used for rapid purification of nucleic acids, combines the speed and efficiency of silica-based nucleic acid purification with the convenient handling of magnetic particles and enables purification of high-quality nucleic acids that are free of proteins, nucleases, and other impurities. The purified nucleic acids are ready for direct use in downstream applications, such as amplification or other enzymatic reactions. It can be used to purify nucleic acids from viruses.

Norovirus genotype profiles may help to find origins of outbreaks [95]

Noroviruses are members of the family Caliciviridae and recognized as major pathogens in outbreaks of gastroenteritis worldwide. They can survive in the environment, can use different transmission routes, and have a low infective doses. Transmission occurs through contact with shedding persons; food contaminated during processing, preparation or serving; sewage-contaminated water used for consumption, cultivation or irrigation of food; contaminated aerosols resulting from vomiting; and environmental contamination.

Verhoef and colleagues 20101 described six genotype profiles of Norovirus outbreaks: A) food or B) humans; C) person-borne outbreaks; D) food handler-borne outbreaks; E) outbreaks with an unknown mode of transmission; and F) routine monitored bivalve mollusks. Their study may help to detect the sources of the foodborne outbreaks resulting from infected food handlers and those resulting from food contaminated early in the food chain. The authors stress that differentiating between person-borne or food handler-borne outbreaks is of public health interest because different control measures are applicable, such as prevention measures during the production process, detection should enable containment of viral foodborne infection and thus prevent further spread and the consequent potential for large numbers of human infections.

The authors urge, however, that genotyping data need to be interpreted with care, and continuous updating of the database remains necessary.

Norovirus genogroup I and II [93]

There is no cell culture system available for the multiplication of human noroviruses. The detection by ELISA is not recommended due to norovirus genetic diversity and its lack of sensitivity. Molecular techniques (real time RTPCR) are the methods of choice for Norovirus detection after extraction and viral RNA purification from the sample.

Bottled water: Attachment of Enteric Viruses to Bottles [96]

Butot and colleagues 2007 developed an internationally accepted virus detection methods for bottled water, facing some doubts concerning its safety due to the reported finding of norovirus sequences in 33% of commercially available water samples sold in Switzerland. [97] However, this could not be confirmed by other studies. A standard method therefore was welcome:

Storage of water that was deliberately contaminated with enteric viruses in polyethylene terephthalate (PET) bottles led to a rapid decrease of the apparent viral load, due to adhesion adsorbed norovirus, and rotavirus on bottle walls. This was also observed with glas bottles.

The virus retention on PET bottle walls after 62 days reached an average level of up to 95% of the recovered inoculum of norovirus, hepatitis Elution of the virus from bottle walls using the described method on 294 commercially available water bottles obtained from 25 different countries did not give any positive result.

The authors concluded that the sources used for bottled water are free from enteric viruses and support the theory that bottled water is not a vehicle for viral diseases.


Reo virus

infects intestines, lung, kidneys, liver and spleen of cattle and swine.


Rotavirus

in the intestines of cattle and swine.
Rotaviruses belong to the group of the reovirus. The particles of rotavirus contain 11 segments of double-stranded RNA. They are 70 nm in diameter and resemble wheels with a central axis and radiating spokes.
Rotaviruses are the major agent of non-bacterial diarrhoeal diseases with great risk to infants and young children. The large majority of gastroenteritis are due to group A rotavirus. Transmission occurs commonly through water.


Astro virus


Adenovirus

is found in intestines, lung, kidneys of cattle and swine


Canine parvovirus

The members of the group of the parvoviruses are roughly spherical with a diameter of about 24 nm. Canine parvovirus causes enteritis and miocarditis in dogs.

Coxsackie virus

It is found in the intestines and lung of swine.

ECHO viruses

Corona virus

infects the intestines of cattle.

Newcastle virus

Norwalk virus

from infected mussels

Herpes virus

It infects lung liver spleen, milk and muscles of cattle and lung and muscles of swine.

Other entero viruses

Infection occurs through fecal contamination of food, water and air. Personal hygiene, communal hygiene such as sewage treatment and isolation of diseased persons from food processing are the most important measures to avoid food born diseases.

The contamination can be of primary or secondary nature.
The primary contamination of food occurs when the animal which is going to be killed has already a virus disease. Meat and organs may then carry the virus. Fish and oysters near the estuary of sewage carrying rivers may bear hepatitis viruses.

The secondary contamination of food occurs during processing, transportation and storage through dirt and smear infections. Virus carrier of hepatitis - A virus may contaminate food handling food in restaurants.

Water which bears viruses is the most common cause of contamination when used in the production of food or used in cleaning of tools and equipment. Enteroviruses are the most important group of water-borne viruses.

Food poisoning from mussels, oysters and clams

Bivalves are important vehicles for the transmission of enteric diseases when eaten raw or undercooked.

Vibrio species, are abundant in bivalve tissue. According to Carla Pruzzofrom the University of Genova, immunity in bivalves is carried out by circulating haemocytes and soluble haemolymph factors that act in a co-ordinated way to kill microorganisms. Studying the physiology of the Mediterranean Mytilus galloprovincialis, the scientists identified a rage of factors that are important in determining the fate of vibrio cholerae within the bivalve host. These are bacterial surface ligands, soluble hemolymph components and the ability of bacteria to influence distinct signalling pathways responsible for the haemocyte immune response. [98]


Hepatitis A - virus

The HAV is a heat resistant RNS from the family of the Picornaviridae.


Hepatitis E - virus

The HEV is supposed to be a member of the Calici - group. It is a RNS - virus, its incubation is about 40 days. It causes a high mortality between pregnant by first infection. It is very frequent in India and Mexico.


Definition of virus

Viruses are obligate intracellular parasites, they can only multiply inside living cell. Definition according to S.E. Luria and James Darnell (1967):

"Viruses are entities whose genomes are elements of nucleic acid that replicate inside living host cells using the cellular synthetic machinery and causing the synthesis of specialised elements (virus particles) that transfer the virus genome to other cells."
This definition should be added by 5 characteristics enumerated by A. Lwoff (1957):
Viruses are extremely small microorganism ( 15 - 300 nm which can pass normal bacterial filters).
  1. They contain only DNA or RNS
  2. There is no division. Reproduction occurs by only means of nucleic acid.
  3. There is no growth in the extracellular latent phase.
  4. There are no metabolic enzymes
  5. Replication by means of the ribosomes of the host cells


Groups of viruses

Viruses are generally divided into animal viruses, plant viruses and bacterial viruses.
The division of viruses in to groups is important as they do not cross the boundaries as they are specialised to the biology of their hosts. Only a few viruses , however can do that. This is the case of the rhabdovirus group

Animal viruses

are viruses which infect vertebrates, including human viruses of medical importance and those of veterinary importance.
The name of animal viruses are based on the disease caused on the principal host followed by the name virus.

invertebrate viruses

especially insect viruses.

Plant viruses

such as mosaic virus of tobacco and viruses of flowering plants.
The name of plant viruses are given according to the major host of plant and the main symptoms of disease caused such as tobacco mosaic virus (TMV), tomato bushy stunt virus (TBSV)raspberry ringspot virus (RRV). (On regard of the problems of classification please refer also to "Phytopathology"

Bacterial viruses

are also known as pages, bacteriophages. Well known are the phages which infect Escherichia coli.
Bacterial viruses are named by code letters or by a system of letters and numbers
Bacterial infections may be a lytic infection such as caused by phage T2 or T4 infecting Escherichia coli causing it to burst which is called lyse. The phages infection of bacteria may be lysogenic, infected cells of bacteria show no signs of infection but retain the ability to produce infective virus particles.

Nipah virus and Hendra virus [99]

cite

Hendra
Both viruses are member of the family of Paramyxoviridae both are included in the genus of Henipavirus. They are known to be able to infect a wide rage of hosts ( pigs, horses,cats, dogs and guinea pigs). The natural host of the Nipah virus are certain species of fruit bats (Megachiroptera such as Pteropus vampyrus) which are infected without being ill themselves.
Though Nipah and its closely related zoonotic Hendra virus ( formerly called Equine morbilli virus EMV) are not known to be transmitted by food there are cases known of transmissions from pigs and horses to mankind.So breeders and abattoir workers should take special care to avoid infection leading with sick pigs with Nipah virus infections.Sick horses with severe respiratory disease were reported to be the source of infection with Hendra virus in Australia. Once infected the death rate in humans is higher than 50%. There is no medication against the viruses. Only ribavirin can reduce the severity of the disease.
It is recommended that close contact with body fluids and infected tissues should be avoided if Nipah infection is suspected. Respiratory secretions of diseased humans and animal contain the viruses.
In an Malaysian outbreak in Nipah infected pigs were the cause of human disease. The virus carries therefore this name.
Incubation time is between 4 and 18 days in some cases up to twelve months and is in most cases sub-clinical with influenza-like symptoms, high fever and muscle pains.Inflammation of the brain,drowsiness, disorientation, convulsions and coma.


Menangle virus

Menangle virus, a member of the Paramyxovirus family causes a disease in pigs with stillborns and deformed piglets and influenza-like illness in humans. Its host are fruit bats.


Tioman virus

Tioman virus is a member of the Paramyxovirus family and of the genus Rubulavirus. It is related to Menangle virus.

Newcastle Disease in pigeons in Germany [100]

Friedrich-Loeffler Institute in Germany confirmed the outbreak of paramyxovirus-1 Newcastle Disease in pigeons at the border of Bavaria with Austria. on 22.4.2008. The veterinarian Dr. Barbara Hohhmann reported 33 cases at a farm in Rottal-Inn Bayerbach. The applied control measures were quarantine, movement control inside the country, zoning and disinfection of infected premises.

Chickens, turkeys, pigeons and ducks may be affected. In ducks the disease is rarely diagnosed but causes production drops and fertility problems. Mammals may be occasionally affected, such as conjunctivitis in man. [101]

Other viruses

they infect protozoa, algae,filamentous fungi and yeasts. They are not so well known.


Structure of virus particles

The structure of virus particles can be determined with electron microscopy and X-ray crystallography. In 1939 a tobacco mosaic virus TMV was seen for the first time using an electron microscope.
Virus particles are transparent in the electron beam, special staining is therefore necessary:


Shadow casting

Metals such as gold are vaporized and sprayed over the virus particle, forming a thin film over the object. The resulting shadows are used to analyse the three-dimensional structure of the particle.


Negative staining

Heavy metal salts are used as negative stains such as potassium phosphotungstate or uranyl acetate. These compound fill the gaps between particles giving rise to the image of the details of the particle against a dark background.


R-ray crystallography

X-ray Crystallography can be used whenever the virus particles can be isolated in crystalline form. This method was used with viruses such as: Polio virus and tobacco mosaic virus.
The external morphology is made by a protein shell called capsid. Capsids are composed of subunits called capsomeres
The capsomeres may contain several proteins such as the capsomeres of the particles of poliovirus.These proteins are called virion proteins VP Polioviruses have virion proteins VP1, VP2, VP3, VP4.
According to the morphology the viruses may be classified:


Icosahedral symmetry

They are small and infect animals such as poliovirus, plants such as turnip yellow mosaic virus (TYMV) and bacteria. Their morphology resembles an icosahedron.


Helical symmetry

Viruses which are rod shaped and have helical arrangement of their subunits are called helical symmetry viruses.
Rod shaped viruses can be rigid as seen by the tobacco mosaic virus or flexible as found with the potato virus X and mumps virus.


Enveloped virus

Enveloped viruses have a lipid-rich outer coat forming a regular phospholipid bilayer similar to the cell membranes of eucariotic cells. The shape can vary, being called pleomorphic particles.
Some glycoprotein structures emerge from the lipid coat. These structures are called peplomers or spikes, such as seen in influenza virus
Some viruses have haemaglutining spikes HA which stick to the surface of red blood cells causing clumping of blood.
The envelope is essential for the infection process. Treatment with detergents or organic solvents such as chloroform or ether damages the lipoprotein layer and inactivates the virus.


Complex virus particles

There are two types of complex virus particles known:
Poxvirus and Phages


Poxviruses

They have a central nucleoid core of DNA covered by a lipoprotein membrane with spikes.
Poxvirus particles can be brick shaped such as smallpox or ovoid as in orf which is a poxvirus of lamb and kid goats


Phages

Are virus particles with a head of icosahedral symmetry and a tail of helical symmetry. Examples of phages are the T2, T4 and T6.

Genetic variations of viruses

Genetic variation of viruses modify their reaction to specific antibodies giving place to new strains of viruses. One distinguishes antigenic drifts and antigenic shifts.


Antigenic drifts

The mutation of the genes may be very small. They are point mutations, changing simple aminoacids of the HA and the N proteins. These small antigenic drifts explain the appearance of mild epidemics such as influenza being only of local importance.


Antigenic shifts of viruses

The changes of the genetic code is very great and new strains of viruses appear. They are responsible for world-wise influenza epidemics.

Virus infection due to contaminated water

Contaminated surface water can be the cause of virus epidemic diseases when chemical disinfectants without slow filtration through sand or flocculation is used.
Concentration of chemical disinfectants may be sufficient to destroy Escherichia coli but not enough to inactivate viruses. Despite a negative coli test contamination with viruses are still possible. Some viruses found in water are:
The amount of virus particles in contaminated water can be very low , the water still remaining infectious for humans. New laboratory method are being applied to control virus contamination of water. These methods are DNA and RNA sondes and control of specific nucleic acid sequences with hybrid techniques as well as the polymerase chain reaction

Food may be contaminated by food preparers or handlers who have viral gastroenteritis, especially if they do not wash their hands regularly after using the bathroom. Shellfish may be contaminated by sewage, and persons who eat raw or undercooked shellfish harvested from contaminated waters may get diarrhoea. Drinking water can also be contaminated by sewage and be a source of these viruses.

Viral gastroenteritis outbreaks can occur in schools, child care facilities, nursing homes, banquet halls, cruise ships, dormitories, and campgrounds

Rotavirus infection can be diagnosed by laboratory testing of a stool specimen. Tests to detect other viruses that cause gastroenteritis were not in routine. Genetic fingerprinting technology using PCR methods, can now identify many common foodborne illnesses and find their origin with great accuracy. Infection of the most of the viruses occurs through faecal contamination of water food and air.

Vaccination reduces severity of rotavirus infections [102]

Pitzer and colleagues developed a mathematical modelling based on changing patterns of rotavirus transmission in the United States. The model includes regional birth rates and predicted vaccination levels and effectiveness. It says that when 80 percent or more of children in a given population are vaccinated, annual epidemics may occur on a less regular basis and more unvaccinated children will be protected. The study explains the timing of rotavirus epidemics dependent on the birth rate in the population because newborns infants have an untrained immune system.

With the introduction of vaccination the rotavirus outbreaks may become less frequent and less pronounced as it was before vaccination. Pitzer stresses that despite uncertainties in the demographic differences and unpredictable conditions the introduction of vaccination in the developing world will decrease rotavirus death rates which is high in children under 5 years in developing countries.


Measures to avoid food born viral diseases

Personal hygiene, communal hygiene such as sewage treatment, isolation of diseased persons from food processing.

The contamination can be of primary or secondary nature. The primary contamination of food occurs when the animal which is going to be killed has already a virus disease. Meat and organs may then carry the virus. Fish and oysters near the estuary of sewage carrying rivers may bear hepatitis viruses.

The secondary contamination of food occurs during processing, transportation and storage through dirt and smear infections. Virus carriers of hepatitis-A virus may contaminate food in restaurants. Water which bears viruses is the most common cause of contamination when used in the production of food or used in cleaning of tools and equipment or rinsing vegetables. Enteroviruses are the most important group of water-borne viruses.

The human pathogens in these groups have been poorly studied since for the most part, they do not grow in culture. They have been grouped on the basis of their appearance. Recently, nucleotide sequences of members of each group have been determined, allowing genome organisation to be used as a basis for future classification.

In the past, the cause of food poisoning could not be found. Health officials named a particular food product or brand not until many people became ill because of recourse.

Sometimes they acted to fast removing a product from the market which were not contaminated, damaging the reputations of innocent food growers, manufacturers, and vendors. This happened with Birkel noodle in Germany. The company was blamed to have used spoiled eggs for here products. The company proved its innocence but almost went into bankruptcy.


Reoviruses

Respiratory Enteric Orphan viruses, i.e. infect the human respiratory and intestinal tracts, usually without disease symptoms. There are 150 species in the family Reoviridae. They are a diverse group, infecting invertebrates, vertebrates and plants, but are unified by their most unique feature, the composition of their genome.

Bluetongue virus

Bluetongue is an insect transmitted, viral disease of domestic(cattle and sheep) and wild ruminants that is caused by bluetongue virus (BTV).

Human infection are unknown, and there is no risk of the disease being contracted or spread through meat or milk.
The Bluetongue virus is a member of the genus Orbivirus and Reoviridae family. There are 24 serotypes. It is transmitted by a midge Cullicoides imicola and other culicoid species. In August 2006 cases of bluetongue were found in the Netherlands, then Belgium and Germany. Major signs are high fever, excessive salivation, swelling of the face and tongue and cyanosis of the tongue. Swelling of the lips and tongue gives the tongue its typical blue appearance, though this sign is confined to a minority of the animals. Recovery is very slow.

Report on Epidemiological analysis of the 2006 bluetongue virus serotype 8 epidemic in north-western Europe updated in June 2007 [103]

Bluetongue (BT) is an arthropod-borne viral disease caused by the BTV-serotype 8 (BTV-8) It affects domestic and wild ruminants, particularly certain breeds of sheep. It is a severe clinical disease, including mortality which rapidly spread in north-western Europe in 2006 . It affected cattle and sheep holdings in Belgium, Germany, France, Luxembourg, and The Netherlands.

The main findings reported by the EFSA bluetongue working group

Statistical modelling showed that the initial infection occurred in the area close to Maastricht. The source of the introduction of BTV-8 could not be identified and the exact origin and route of the introduction of BTV-8 thus far remains unknown. However, the absence of legal import of ruminants from outside the EU into the Area of First Infection and the absence of BTV-8 from southern Europe suggest that the introduction of the BTV-8 infection into north-western Europe is likely to have occurred via a other than through import of infected ruminants.

Specifically, the potential for Culicoides to be imported along with or independently of the import of animals, plants or other materials merits further study.

Blutongue virus serotype 8 reemerges in Germany [104]

Martin Beer and colleagues 2008 report that bluetongue virus (BTV) is a double-stranded RNA virus of the genus Orbivirus. BTV is transmitted to its hosts by the bite of Culicoides spp. midges. It causes a noncontagious, arthropod-borne disease of domestic and wild ruminants and camelids; disease can be serious, particularly in sheep. BTV had never been reported in any European country north of the Alps until August 2006, when outbreaks of BTV serotype 8 (BTV-8) were almost simultaneously discovered in the Netherlands, Belgium, Germany, and France. In 2006, a total of 893 cases were detected in Germany, but the source of initial virus introduction remains unknown. Subsequently, BTV-8 overwintered in the region, spread over most of the country, and led to almost 21,000 new cases in 2007 in Germany. BTV-8 infections spread to additional European countries, e.g., the United Kingdom, Switzerland, the Czech Republic, Denmark, and Spain.

In February 2008 bluetongue virus serotype 8 (BTV-8) was detected in Germany in an export heifer. According to the authors reemergence was confirmed by retesting the samples, experimental inoculation, fingerprinting analysis, and virus isolation. The authors stress that overwintering of BTV-8 and continuous low-level infections are assumed.

Monitoring

Sheep flocks should be monitored by a system based on clinical signs, as PCR in affected sheep is often negative.

Cattle monitoring system based on serological surveillance is being recommended.

Culicoides as a vector of BTV

The BTV-8 virus was found to be present in vectors (Culicoides species) which are endemic to north-western Europe. C. imicola, which is thought to be responsible for at least 90% of BTV transmission in the Mediterranean Basin, was not found in the affected region. Indigenous Culicoides found to be PCR-positive were C. dewulfi (a species breeding exclusively in the dung of cattle and horses) and C. obsoletus/C. scoticus.

In all likelihood this persistent activity of adult Culicoides owes much to the mild temperatures that have continued to prevail across northern Europe during the winter of 2006/2007.

Local spread was modelled and found to occur at a rate of about 2 km per day or approximately 15 km per week and equals the flight distances covered by Culicoides.

Wind may affect spread over long distances. In particular, the density of the observed wind events contributed, at least in part, to explaining the spread of BTV.

In conclusion, changes in climatic conditions coupled with increased worldwide traffic might increase the risk in the appearance and the establishment of diseases in parts of Europe that were thus far exotic to those regions.


Rotaviruses

Rotaviruses belong to the group of the reoviruses. They resemble wheels with a central axis and radiating spokes (Rota=Wheel)

Rotaviruses are the most common cause of severe diarrhoea worldwide. In developing countries, rotavirus infection may cause up to one million deaths each year. Clean water and improved sanitation are seldom available in developing countries. Rotavirus particles remain active on human hands for at least 4 hours, on hard dry surfaces for 10 days, and on wet areas for weeks.

The large majority of gastroenteritis are due to group A rotavirus.
Adsorbed on particles, they can survive in different kind of environment for a long period.

Food can be contaminated by a food-handler during the various stages of food production or via the environment. Thanks to their structural properties, rotaviruses can persit to different food processes. The consumption of contaminated food can lead to outbreaks in population. The diagnostic by cellular culture or ELISA is not adapted to the detection of rotavirus in environmental or food samples.

Molecular techniques (real time RT-PCR) are the methods of choice for rotavirus detection after extraction and viral RNA purification from the sample. Although the rotavirus and the Norwalk family of viruses are the leading causes of viral infects other viruses can also cause diarrhoea. [93]


Astroviruses

Astroviruses are the cause of most frequent viral gastrointestinal infections and are a significant cause of diarrhoea in developing countries.

They are clinically similar to caliciviruses. Astroviruses have been isolated from birds, cats, dogs, pigs, sheep, cows and man. There are at least 7 human astrovirus serotypes. Outbreaks in UK, in Mexico and food borne astrovirus infection in Japan involving thousands of children and adults.


Adenoviruses

Adenoviruses most commonly cause respiratory illness; however, depending on the infecting serotype, they may also cause various other illnesses, such as gastroenteritis, conjunctivitis, cystitis, and rash illness.

Adenoviruses are unusually stable to chemical or physical agents and adverse pH conditions, allowing for prolonged survival outside of the body. Transmission occurs by direct contact foecal-oral transmission, and occasionally by water. Shedding can occur for months or years.

An adenovirus deadly for monkeys deadly was found to infect Humans [105]

The UCSF Viral Diagnostics and Discovery Center identified a new adenovirus (titi monkey adenovirus TMAdV) infecting New World titi monkeys and two humans, jumping between the animals and humans. TMAdV caused an upper respiratory illness which progressed to pneumonia and a death rate of 83% of the monkeys at the Center.

Adenoviruses are known to infect humans and many animals like monkeys and rodents. In humans, the adenoviruses cause diseases associated with cold-like symptoms, diarrhoea or pneumonia. The authors report that the new virus is the first adenovirus which is able to cross the human-monkey species barrier. Crossig the species barrier is known for influenza and coronaviruses, but had been unknown for adenoviruses. The monkeys and researcher and two members of his family tested positive for antibodies to the TMAdV virus.

The UCSF used for this study the pan-viral microarray platform Virochip has the capacity to detect all known viruses as well as novel variants on the basis of conserved sequence homology, identifying novel viruses, such as the SARS coronavirus, a novel rhinovirus clade, XMRV (a retrovirus linked to prostate cancer), avian bornavirus (the cause of a wasting disease in parrots), and a novel cardiovirus in children with respiratory and diarrheal illness. [106]

The new virus shares only 56 percent of its DNA to its closest viral relative and is very deadly to titi monkeys. The authors suggest therefore that these monkeys are not the primary host of the virus which is still unknown, but might have its origin in Old World monkeys deducing from a positive test for TMAdV antibodies for one monkey with Old World origin.


Parvoviruses

Parvoviruses are associated with human gastroenteritis. Shellfish have been implicated in illness caused by a parvo-like virus.

Although foods are not analysed in routine for these viruses, it may be possible to apply current immunological procedures to detect viruses in clinical specimens. Gene probes and PCR detection methods are currently being developed. In near future a better surveillance of these epidemics will increase food safety.

Quality assurance programs in slaughterhouses should reduce fecal contamination of carcasses and meat should be chilled rapidly.

Monitoring trends of indicator organisms, e.g. Enterobacteriaceae and Standard Plate Count should indicate deviations from quality standard A general method for E.coli detection i.e. for non-pathogenic and potentially pathogenic strains, is also useful as levels of all types of E.coli should be minimised in food production.

Any increase of normal levels or indicators should trigger an active investigation of the reasons for the increased levels.

Effective process control of all cooking / pasteurisation stages is essential to ensure that the correct heating temperatures and times are achieved.


SARS Severe Acute Respiratory Syndrome

SARS coronavirus (SARS-CoV) type causes an epidemic of a respiratory disease which spreads in Guangdong and other provinces of Chin, Canada, the United States. The virus may remain on hands and surfaces for several hours.

Strict hand-hygiene be enforced among food handlers and within the food processing industry. This should be done very carefully after using the restroom and after sneezing or coughing. In addition, food workers should not handle ready-to-eat foods, such as sandwiches, vegetables and cut fruits, with bare hands, but should use gloves or utensils for an extra level of protection. The SARS global outbreak of 2003 was contained; however, it is possible that the disease could re-emerge.

Proper hand washing continues to serve as a vital and necessary public health practice to eliminate the spread of food borne illnesses in retail food stores and food service. Contamination factors common in retail and food service environments inhibit the effectiveness of alcohol-based hand sanitizers when used in place of hand washing.

Corona viruses are named for their corona-like appearance. The corona or halo is due to an array of surface projections on the viral envelope, one of which is the E2 glycoprotein, the viral attachment protein. Corona viruses are second only to rhinoviruses as a cause of the common cold and pneumonia.

Infectious Laryngotracheitis in poultry

Infectious Laryngotracheitis is a viral infection of the respiratory tract of chickens, pheasants and peafowl. It can spread rapidly among birds and causes high death losses in poultry that are susceptible. The disease is not a human health risk. Turkeys, ducks and geese do not get the infection but could spread the virus.


Mycoplasmosis

Mycoplasma gallisepticum is associated with chronic respiratory disease (CRD)/air sac syndrome in chickens and turkeys and infectious sinusitis of turkeys; Mycoplasma meleagridis is associated with airsacculitis in turkeys; and Mycoplasma synoviae is the cause of infectious synovitis in chickens and turkeys. Mycoplasma are bacterial-like organisms.


Mareks Disease

Mareks is a member of the herpesvirus family of viruses. It causes internal tumours. The most common Mareks in chictumoursre eye, visceral, and nerve versions. The turkevisceralon is Herpes Virus Turkey. The waterfowl version is known as Duck Virus Enteritis. All three are from the same family of viruses.

Vaccination in China [107]

Using a technique called reverse genetics, scientists at the Key Laboratory of Animal Influenza, affiliated to Harbin Veterinary Research Institute, altered the genome sequence of the virus to construct a vaccine that is believed to be safe to both poultry and mammals.

The vaccine will be administered to fowls in the country's key water areas, including rivers and lakes. Laboratory tests show the vaccine enables ducks and geese to fight H5N1, the highly lethal strain of bird flu, three weeks after the flocks were vaccinated, the statement claimed. The new vaccine also provides at least 10 months of protection for chickensfour months longer than the existing bird flu preventive drugs.

China developed advanced bird flu virus test technology (RT-PCR reagent kit) last April. This can detect H5, H7 and H9 subgroups of the bird flu simultaneously in several hours.

Vaccination is a must for water fowls and poultry farms in Chinese regions at high risk, according to a national tele-conference in bird flu prevention on January 28 in Beijing.

Apart from the encouraging laboratory test results, field tests also indicate that upon receiving two shots of the vaccine, ducks and geese can each produce antibodies effective for 10 months and three months, respectively.

According to the ministry statement the vaccination thus makes it impossible for ducks and geese to become the load of H5 subgroup bird flu virus. Therefore, it can cut a key link for the highly pathogenic avian influenza to spread.

German officials , however say, vaccination is not the solution of the problem. In Italy nobody can say if poultry is free of H5N1 because some flocks were vaccinated using an attenuated virus H7N3. Imunity against all H7 (Hafez) Vaccinated poultry cannot be exported. Under European law, any vaccinated birds would face restrictions on movement which would prevent export and allow them only to be transported to a slaughterhouse.

Britain continues to oppose the vaccination programme on grounds of both cost and effectiveness, as do Germany, Austria, Denmark and Portugal.

Vaccinated birds could incubate the disease without showing symptoms, allowing low-level spread among flocks and increasing the likelihood of its mutation into a form transmissible to people.

Neuraminidase is the protein which gives the number to N. There are only two laboratories which can type the N number. One is located at the island Riems (Germany) and the other is the EU reference laboratory located in England.

In Germany researches on a vaccine is being done at the Bundesforschungsinstitutes für Tiergesundheit, Im Friedrich-Loeffler-Insitut (FLI) Thomas Mettenleiter says they are working on recombinant serum which can be sprayed instead of having to be injected on every bird. They could have a marker effect which could be easily detected. A vaccine which will take two to three years to be ready to use.

EU measures to limit the spread of avian influenza

The European Commission measures designed to limit the disease are approve member states' individual surveillance plans for avian influenza and to provide up to 50 per cent co-funding for these programmes.

The measures include a three km "protection zone" around the place where the birds with H5 infection were found for at least 30 days along with a 10 km "surveillance zone" for the next three weeks.

Within the protection zone poultry must be kept indoors. All movement of poultry, excluding direct transportation to a slaughterhouse is banned. No meat may be transported outside the protection zone.

In both the protection and surveillance zone farm biosecurity measures must be strengthened and the hunting of wild birds is banned. All bird markets and exhibitions are banned.

Early warning measures are in place in all member states to ensure quick detection of the disease, both in domestic and wild birds. Contingency plans call for the rapid control and eradication of avian influenza should it occur in poultry farms.

Indonesia vaccinated 114 million poultry against avian flu with traditionally made vaccine in 2004. India last week confirmed the presence of avian flu and has started a mass culling of poultry.

In February 2006 the French government ordered all domestic birds indoors.

Wild birds with highly pathogenic avian influenza have been detected in France, Slovakia, Slovenia, Italy, Greece, Austria, Hungary and Germany, in addition to the accession countries Bulgaria and Romania and Turkey.

Affected EU member states are implementing strict protection and surveillance zones around the location where H5N1 infected wild birds have been found. In addition, the EU has approved the vaccination of bird flocks in certain areas of the Netherlands and France.

Vaccination is being permitted in selected southern areas of France that are believed to be at risk from avian influenza. The free-range ducks and geese in this region are not easy to put "indoors" and are therefore at risk of contact with wild birds that may be carrying the virus, according to an European Commission report.

The vaccination programme will begin immediately and will continue until 1 April 2006. Sentinel birds, which are unvaccinated control birds, will be used as part of the monitoring for avian influenza.

Vaccinated poultry, their hatching eggs and day-old chicks cannot be exported or moved to any third country, including countries in the EU. There are strict conditions on the movement of vaccinated birds within France. Fresh meat and meat products from vaccinated poultry will be able to be sold in the EU, provided the safety conditions have been complied with by the farm.

Indonesia vaccinated 114 million poultry against avian flu with traditionally made vaccine in 2004. India last week confirmed the presence of avian flu and has started a mass culling of poultry. The Food and Agriculture Organisation (FAO) has warned that the virus could become entrenched in the Black Sea, Caucasus and Near East regions through trade and movement of people and animals and it could be further spread by migratory birds particularly coming from Africa in the spring.

According to FAO fighting the avian influenza virus in animals is the most effective and cost-effective way to reduce the likelihood of H5N1 mutating or reassorting to cause a human flu pandemic. Containing bird flu in domestic animals-mostly chickens and ducks-will significantly reduce the risk to humans. Avian influenza should not only be considered as a human health issue, but as a human and animal health issue.

Extraordinary collective effort to address avian flu

According to a study of Anna Thorson and colleges the verified human cases of highly pathogenic avian influenza in Vietnam may represent only a selection of the most severely ill patients.

Epidemiological data are consistent with transmission of mild, highly pathogenic avian influenza to humans and suggest that transmission could be more common than anticipated, though close contact seems required. However, the virus is more widespread than thought[108]

According to Kofi Annan, Secretary-General, United Nations (2005), a threat like a flu pandemic cannot be addressed by one organisation, one group of countries, one sector or one profession. It presents us with an extraordinary collective challenge, and it calls for an extraordinary collective effort.

On 29 November 2005, the Commission adopted a communication calling for the strengthening of EU-wide coordination in tracking and responding to avian flu.

Vaccine against H5N1 for humans

[109] In March 2005, Sanofi Pasteur, the French vaccine manufacturer, released the first vaccine made for humans directed against the avian influenza A H5N1 virus for testing and evaluation by virology laboratories. Tests showed it was effective, but in a much higher than usual dose. The Sanofi Pasteur H5N1 avian flu vaccine is unlikely to be of much use against the virus because the flu virus is always changing. While vaccination is our best hope of avoiding catastrophe, it is pretty certain that none will be available when the first wave of the pandemic spreads across the globe.

Low dose vaccine against H5N1

A 10 mg vaccine that contains a modified version of the whole H5N1 virus plus adjuvant was tested in China in 2006. This vaccine is effective at low doses allow more people to be immunised. [110]

Vaccine using fertilized eggs

Vaccine production using fertilized eggs takes 6 to 8 months under the best of circumstances, it has been more difficult than usual with the H5N1 strain because it is so lethal that it kills chicken embryo before there is enough time raise a good yield of vial particles.

This type of vaccine requires two high doses, one month apart. Research is looking for a vaccine that requires much smaller doses so that manufacturers can rapidly produce more vaccine doses. For this new methods of producing vaccines are discussed:

Vaccine with aluminium adjuvant

An adjuvant such as aluminium or gold particles attached to the vaccine can boost the immune response. By increasing the immune response, smaller doses of vaccine may be used, helping the manufacturers to produce more doses. The administration of the vaccine would be easier using air pistols instead of injection by needls.

EFSA Advises on the Safety of Aluminium in Food [111]

Europe's food safety watchdog established a Tolerable Weekly Intake (TWI) of 1 milligram of aluminium per kilogram of body weight. The mean dietary exposure of adults varied from 0.2 to 1.5 mg/kg bw/per week. In children and young people, the highest exposures ranged from 0.7 to 2.3 mg/kg bw/per week. The TWI of 1 mg/kg bw/week is therefore likely to be exceeded in a significant part of the European population.

Children generally have higher food intake than adults when expressed on a body weight basis, and therefore represent the group with the highest potential exposure to aluminium per kg body weight. Large individual variations in dietary exposure to aluminium can occur. In children and young people the potential estimated exposure at the 97.5th percentile ranged from 0.7 mg/kg bw/week for children aged 3-15 years in France to 2.3 mg/kg bw/week for toddlers (1.5-4.5 years) and 1.7 mg/kg bw/week for those aged 4-18 years in the UK. Cereals and cereal products, vegetables, and beverages appeared to be the main contributors (>10%) to the dietary aluminium exposure in the general population.

The major source of exposure to aluminium in foods originates from its natural occurrence, from the use of food additives containing aluminium and from the presence of aluminium in food contact materials such as pots, pans and foil. The main contributors to aluminium intake from the diet are cereals and cereal products (such as bread, cakes, biscuits and pastries) vegetables (such as mushrooms, spinach, radish and lettuce), beverages (such as tea and cocoa) and some infant formulae. Drinking water is a minor source of exposure. Additional exposure may arise from pharmaceuticals and consumer products containing aluminium compounds.

The Panel based its evaluation on the combined evidence from a number of animal studies showing adverse effects on testes, embryos and the developing and mature nervous system following dietary administration of aluminium compounds.

Aluminium has shown neurotoxicity in patients undergoing dialysis and thereby chronically exposed to high concentrations of aluminium. It has also been suggested that aluminium is associated with Alzheimer's disease and other neurodegenerative diseases in humans; however, based on the available scientific data, the Panel did not consider exposure to aluminium through food to present a risk for developing Alzheimer's disease.

Under normal and typical conditions the contribution of migration from food contact materials would represent only a small fraction of the total dietary intake. However, the Panel noted that in the presence of acids and salts, the use of aluminium-based pans, bowls, and foils for foods such as apple puree, rhubarb, tomato puree or salted herring could result in increased aluminium concentrations in such foods. Also, the use of aluminium vessels and trays for convenience and fast food in might moderately increase the aluminium concentrations, especially in foods that contain tomato, different types of pickles, and vinegar.

Aluminium in infant formulae

In infants aged 0-3, 4-6, 7-9 and 10-12 months, potential dietary exposures from infant formulae and other foods manufactured specially for infants were estimated to be respectively 0.10, 0.20, 0.43 and 0.78 mg/kg bw/week.

Potential exposure to aluminium in 3-month infants from a variety of infant formulae was estimated by the Panel. At the mean it was up to 0.6 mg/kg bw/week for milk-based formulae and was 0.75 mg /kg bw/week for soya-based formulae; at high percentiles of exposure it was up to 0.9 mg/kg bw/week for milk-based formulae and was 1.1 mg /kg bw/week for soya-based formulae.

The Panel noted that in some individual brands of formulae (both milk-based and soya-based) the aluminium concentration was around 4 times higher that the mean concentrations estimated above, leading to a 4 times higher potential exposure in brand-loyal infants.

Potential exposure in breast-fed infants was estimated to be less than 0.07 mg/kg bw/week.

High-dose, but not low-dose of zinc lozenges reduce duration of common cold [112]

Harri Hemilä 2011 reports that high-dose, but not low-dose, zinc lozenges shorten the duration of the common cold. Many studies found diverging results related to the effect of zinc lozenges on the common cold.

In this review Hemilä separated the low-dose zinc and high-dose zinc trials. The trials using a total daily zinc dose of less than 75 mg found no effect on common cold duration, trials using zinc acetate in daily doses exceeding 75 mg showed a 42% reduction in the duration of colds. The trials using zinc salts other than acetate in daily doses exceeding 75 mg, showed a 20% reduction in the duration of colds.

In several trials, the zinc lozenges caused bad taste and constipation, but none of the trials reported long term harm. These adverse effects may have been caused by the specific lozenge composition and are not related to zinc ions per se. No adverse effects were reported with zinc acetate, even at daily dose of 92 mg. No harm is expected treating the common cold for a week with high doses of zinc in the form of lozenges. The author concluded that benefit is observed with high doses of zinc (daily doses exceeding 75 mg) but not with low doses.

Reverse genetics technique

Reverse genetics uses only specific parts of the genetic code of the viruses. This enables to make a generic vaccine with all of the 15 variations from H1 to H15.


Researches on HIV and antiretroviral drugs strategies, the HPTN 035 Study

A retrovirus is an RNA virus that is replicated in a host cell via the enzyme reverse transcriptase to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA. Retroviruses are enveloped viruses that belong to the viral family Retroviridae. The virus itself stores its nucleic acid in the form of a +mRNA (including the 5'cap and 3'PolyA inside the virion) genome and serves as a means of delivery of that genome into cells it targets as an obligate parasite, and constitutes the infection. Once in the host's cell, the RNA strands undergo reverse transcription in the cytosol and are integrated into the host's genome. The HIV virus is the most prominent retrovirus. Antiretroviral drugs are medications for the treatment of infection by retroviruses, primarily HIV. Different classes of antiretroviral drugs act at different stages of the HIV life cycle. [113]

Genetic engineered plant production of a complex HIV drug unites efficiency and low production cost [114]

Sexton and colleages 2009 describe a fusion protein molecule which may be useful as HIV microbicide. It is the combination of the HIV-neutralizing mAb b12 expressed in transgenic plants. This substance has gp120 binding activity and HIV-neutralizing activity in vitro. A combinational protein, also obtained by genetically modifying the plant, unites the mAb b12 with cyanovirin-N, both microbicides act synergistically to control the HIV virus. The fusion protein molecule is predicted to have four binding sites for HIV gp120.

The authors stress that genetic engineering of plant can make the drug affordable for developing countries and turn the production of high quantities possible. Its efficiency was only tested in vitro. The authors deplore the high legislation barriers for new drugs, meanwhile no regulations are set regarding new food supplements to be put on market.


Microbicide gel to prevent HIV infection of women [115]

Sharon Hillier and colleagues 2009, leading the HPTN 035 study reports the prevention of HIV infections in women using a vaginal 0.5% microbicide gel preventing the HIV virus from attaching to cells in the genital tract.

The authors claim that the gels was 30% effective. Several candidate microbicides are being tested in clinical trials, although none is yet approved or available for use. Condoms are very effective to prevent HIV infection, but are often not accepted by the male partner. Applying the gel, women could protect themselves. Infection male to female is more frequent as the infection of men.

The study was conducted in Africa an in the USA during 2005 - 2008, assessing the effectiveness of BufferGel and 0.5% PRO 2000/5 Gel (P) in preventing the following among women at risk for sexually-transmitted HIV infection: bacterial vaginosis, chlamydia infection, genital ulcer disease, gonorrhea infection, herpes simplex virus-2 infection, pregnancy, syphilis infection, trichomoniasis.

HPTN 035 tested two candidate microbicides with different mechanisms of action: BufferGel and PRO 2000 (0.5% dose). BufferGel is designed to boost the natural acidity of the vagina in the presence of seminal fluid. Semen reduces the acidity of the vagina making it more receptive for pathogens that cause sexually transmitted infections, such as HIV. PRO 2000 is an entry/fusion inhibitor that is designed to hamper HIV's ability to attach to and infect healthy cells.

Although the participants in the PRO 2000 study arm had a 30 percent lower rate of HIV infection compared with the Buffer gel, tha placebo gel and a no-gel group. However, 33 percent effectiveness would have been needed to considered the results statistically significant. The authors call therefore for more studies whether PRO 2000 prevents HIV infection in women. [116]

Mathematical models predict higher protection rate in men than women using vaginal microbicides [117]

Results of mathematical models of 2008 simulating clinical trials and population-level transmission of HIV, found that if HIV-positive women using microbicides may develop drug-resistant strains of HIV that are then less likely to be transmitted to men. In the high-risk scenario, the mathematical models predict for the use of microbicides prevention of infection of 21% for women and 27% for men. In the low-risk scenario, the microbicide would be 17% and 18% respectively.

Sally Blower, professor of psychiatry and biobehavioral sciences said that vaginal microbicides are being developed to provide direct protection to women in case of non-acceptance of condom use by men. However, there are also concerns that microbicides could lead to drug resistance if they are used by HIV-positive women.

Impact of climate change on viral pathogens in water [118]

Viroclime project tries to determine the effects of climate change on the dispersal of pathogenic viruses in rivers,lakes and at beaches, and resulting viral water-related diseases. Studies will be performed in Sweden, Spain, Hungary, Greece and Brazil which are vulnerable to climate change (principally rainfall events), and changes in exposure under defined conditions will be estimated.

Bacterial faecal indicator analysis will permit the determination of relationships between virus levels and water quality standards, and also between changes in virus concentration in water and risk to public health activities, such as bathing in polluted water or consumption of shellfish. The Virocline project stresses the importance of gastro-intestinal disease caused by viruses related to climate change. Human-derived viruses are present in sewage and waste water and and have a strong survival in the environment. The project aims to develop tools for routine and quantitative virological monitoring of the environment, and provide baseline virological data from different environments to predict the influence of climate change on virus population and their impact on disease burden.

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