
Subsections
Search for food has always been a struggle to survive. The discovery of fire by
the cave man was an important step in food handling. Spices triggered the
great voyages looking for a new way to the spices from India.
Nowadays the rarest of dishes are available everywhere and there are no
restrictions as to the seasons. Global trade of food has made it possible.
These modern achievements, however, bear the danger to destruct the economic,
ecological and cultural isolated units destabilising the economy of a region
because manpower and products of other regions, with lower production costs,
compete with high cost regions. Ecology is endangered, due to increase of
traffic, and last but not least, the culture and beliefs of isolated regions
are washed out.
Growing international business leads to ever growing food batches, spreading
them over great areas. The control of hazards in food production,
transportation and handling and even the menace of terrorist actions are
getting high priority in the concern of industry, commerce and food health
departments of every nation and is subject of many international standards.
Food producers (agriculture, breeders, fishery, processing factories) are
concerned about these hazards which may cause tremendous costs, loss of
crops, and even lead to bankruptcy.
Catering service establishments and restaurants are liable to recourse in case
of harmful food.
The loss of confidence of their customers due to headlines involving a recall
of a spoiled brand is a nightmare for every manager of discount stores or
global food trade business.
Food health departments and government ministry of consumer safety, such as
Minister Kynast in Germany in the case of BSE scandal are top headlines.
Bacterial infections
Zoonotic disease in humans within the EU [1746]
Zoonoses are diseases or infections, which are transmissible from animals to
humans. The infection can be acquired directly from animals, or through
ingestion of contaminated foodstuffs.
The European Food Safety Authority analysed the data from 2005 and published a
report on zoonotic diseases in humans in December 2006.
EFSA found campylobacteriosis as the most frequently reported zoonotic disease
in humans within the EU. Reported Campylobacter cases increased by 7.8%
compared to the previous year. Fresh poultry meat was found to have the highest
contamination rate with Campylobacter with 66% of samples positive and was
also commonly detected from live poultry, pigs and cattle. The largest
Campylobacter outbreaks were caused by contaminated drinking water.
Salmonellosis remained the second most frequent zoonosis despite the fall of
9.5% compared to 2004.Salmonella was most often reported from fresh poultry
and pig meat where proportions of positive samples up to 18% were detected. In
table eggs, findings of positive samples ranged from 0% to 6%, but over the
past 5 years an overall decreasing trend in occurrence of Salmonella in eggs
was observed. In animal populations, Salmonella was most frequently detected in
poultry flocks.
Egg and bakery products were the most common sources of Salmonella outbreaks,
whereas broiler meat was an important source for both Salmonella and
Campylobacter outbreaks. Foodborne virus outbreaks were most often caused by
drinking water, fruit and vegetables.
For Verotoxigenic Escherichia coli (VTEC) infections and yersiniosis more
informations are needed concerning the serotypes and other virulence factors
related to human pathogenic serotypes. The authors of the Report call for a
harmonisation of the analytical methodology.
| |
Incidence |
Number of |
| Disease |
100,000 people |
reported cases |
| Campylobacteriosis |
51.6 |
197.363 |
| Salmonellosis |
38.2 |
176.395 |
| Yersiniosis |
2.6 |
9.630 |
| Verotoxigenic Escherichia coli VTEC |
1.2 |
3.314 |
| Listeriosis |
0.3 |
1.439 |
| Brucellosis |
0.2 |
1.218 |
| Echinococcosis |
0.01 |
320 |
| Trichinellosis |
0.01 |
175 |
| Tuberculosis due to M. bovis |
0.01 |
119 |
| Rabies |
0.01 |
4 |
| |
Incidence |
Number of |
| Disease |
100,000 people |
reported cases |
Survey on the prevalence of Salmonella in EU poultry in 2006
[1747]
European Community legislation foresees setting of Salmonella reduction targets
for animal population including broiler flocks.
The survey was the second of several baseline surveys to be conducted in the
Community. The sampling of the broiler flocks took place between October 2005
and September 2006.
A total of 11.0% of the broiler flocks was estimated to be positive for
Salmonella Enteritidis and/or Salmonella Typhimurium, the two most common
serovars found in Salmonella infection cases in humans. The Member
State-specific observed flock prevalence of S. Enteritidis and/or S.
Typhimurium varied also greatly, from 0% to 39.3%. The number of positive
samples in a Salmonella positive flock ranged between one and five but at
European Union level 42% of the positive flocks was found positive for all the
five samples taken.
The five most frequently isolated Salmonella serovars from broiler flocks in
the European Union were respectively in decreasing order S. Enteritidis, S.
Infantis, S. Mbandaka, S. Typhimurium and S. Hadar. All these serovars, with
the exception of S. Mbandaka, are frequent causes of Salmonella infections in
humans within the European Union. S. Enteritidis was the most common serovar
and it was detected in 37% of the Salmonella positive flocks. S. Infantis
accounted also for an important proportion of positive flocks (20%). The
serovar distribution varied amongst the Member States, many of them having a
specific distribution pattern of their own.
While the Community reduction target will most likely be set for a transitional
period only for S. Enteritidis and S. Typhimurium, it is recommended that
Member States would address in their national Salmonella control programmes
also other serovars when these serovars are of public health importance in
their country.
Verotoxigenic Escherichia coli (VTEC) in foods: The majority of the
data derives from food of bovine origin (bovine meat, raw milk, cheese and
dairy products, other or mixed meat). The report also contains information
about Bovine Spongiform Encephalopathy, Avian Influenza, Cysticerci and
Sarcocystis parasites and Q fever in animal populations.
[1746]
Germany reported the highest number of tuberculosis due to Mycobacterium bovis
in 2005, followed by The United Kingdom
Bovine tuberculosis and bovine or caprine/ovine brucellosis is still present in
3-4% in bovine/sheep/goat populations.The highest incidences of human
brucellosis have been recorded in Greece, Italy, Portugal and Spain, mostly
Brucella melitensis were responsible for the disease.
Yersinia enterocolitica 0:3 serotype was the dominant type found in the EU.
Germany had the highest number of human infections. Y. enterocolitica is found
in meat and milk, especially pig meat.
Raw milk [1748]
The U.S. Food and Drug Administration (FDA)and the Centers for Disease Control
and Prevention (CDC) are reminding consumers of the dangers of drinking milk
that has not been pasteurized, known as raw milk. Raw milk potentially
contains a wide variety of harmful bacteria - including Salmonella, E. coli
O157:H7, Listeria, Campylobacter and Brucella - that may cause illness and
possibly death.
Since 1987 FDA has required all milk packaged for human consumption be
pasteurized before being delivered for introduction into interstate commerce. This
also applies to other milk products, with the exception of a few aged
cheeses.
According to FDA, proponents of drinking raw milk often claim that raw milk is
more nutritious than pasteurized milk and that raw milk is inherently
antimicrobial, thus making pasteurization unnecessary. Research has shown that
these claims are myths. There is no meaningful nutritional difference between
pasteurized and raw milk, and raw milk does not contain compounds that will kill
harmful bacteria. In fact, raw milk, no matter how carefully produced, may be
unsafe.
[1749]
The Massachusetts Department of Public Health located the source of the
outbreak at the beginning of January 2007. after four people had become ill,
two of whom fatally, The bacteria is believed to have entered the dairy's milk
supply after it was pasteurized.
[1750]
Current state and local regulations throughout the United States specify time
and temperature conditions for pasteurization. These regulations call for milk
to be heated to at least 71.7
C for 15 seconds (i.e., high-temperature
short-time (HTST) process) or to 62.8 C for 30 minutes.
Viable L. monocytogenes could berecovered after minimum HTST treatment
(71.7
C for 15 seconds), although not after treatment at 76.4
C-77.8
C for 15 seconds. This survival was attributed in part to
protection of L. monocytogenes within leukocytes in milk (intracellular L.
monocytogenes organisms are found in milk from infected cows but not in
artificially inoculated milk), but these findings may not be applicable to
usual production conditions.
In another study in which investigators identified cows that had been
naturally infected with L. monocytogenes, proper pasteurization was found to
inactivate L. monocytogenes in milk contaminated through natural infection as
well as in artificially inoculated milk.
World Health Organization Working Group on foodborne listeriosis recently
concluded that "pasteurization is a safe process which reduces the number of
L. monocytogenes occurring in raw milk to levels that do not pose an
appreciable risk to human health"
CDC concludes that improperly performedpasteurization and the occurrence of
contamination after pasteurization are the most likely explanations for the
presence of L. monocytogenes in pasteurized milk.
Efforts to ensure that milk is safe from L. monocytogenes contamination should
focus on promoting proper methods of pasteurization and on identifying and
eliminating sources of postpasteurization contamination.
This risk is heightened in food processing environments, where Listeria
bacteria tend to thrive, particularly in floor drains and other cool, damp
areas. According to health officials, they suspect the Whittier Farms
pasteurized milk was contaminated after the pasteurization process.
The Massachusetts Department of Public Health (MDPH) is recommending that
consumers do not consume Whittier Farms milk products. Because the incubation
period for Listeria can be as long as 70 days, anyone who has consumed the milk
should watch for Listeria symptoms, including fever, muscle aches and sometimes
gastrointestinal symptoms such as nausea or diarrhea. In pregnant women, the
symptoms may be mild, but an infection can cause miscarriage, stillbirth or early
delivery.
[1751]
In November 2007 the USDA launched a new Food Protection Plan, combining
science and information technology to identify potential hazards before they
have an impact. The Food Protection Plan comprises:
Prevention of foodborne contamination: This aims to increase
corporate responsibility to prevent illness. It seeks to identify and assess
vulnerabilities and expand understanding and use of mitigation measures.
Intervention at critical stages in the food supply chain: This
includes inspections and risk-based sampling, risk-based surveillance, and
better detection of signals that indicate contamination has occurred.
FDA more rapide respond to problems: This reduces the impact, and
improve its communication on risks to the public, industry, and other
stakeholders.
Growing resistance to antimicrobials
Relatively high proportions of Campylobacter and Salmonella isolates from
animals and food were resistant to antimicrobials commonly used in treatment of
human diseases. This is especially the case of resistance to fluoroquinolones
in Campylobacter isolates from poultry, where up to 94% of isolates were
reported resistant to ciprofloxacin. Foodborne infections caused by these
resistant bacteria pose a particular risk to humans due to possible treatment
failure. [1746]
[1752] High temperatures during
preparation prevent Campylobacter infections
Examinations by the German official food control authorities of the federal
states detected Campylobacter in around one-third of the poultry meat samples.
Duck meat is also frequently involved.
Campylobacter infections in humans are frequently caused by poultry meat,
including duck breast. Campylobacter bacteria are heat-sensitive and die when
meat is cooked through. As duck breast in traditional recipes is often not
cooked through ("pink duck breast"), its consumption can lead to unpleasant
gastrointestinal disorders caused by Campylobacter bacteria. This risk,
including Salmonella, Listeria, noroviruses and hepatitis viruses, can be
completely ruled out when the internal temperature of the meat during
preparation on the stove or in the oven is 74 degrees Celsius or higher for
more than 10 minutes.
Basic hygiene rules for handling poultry: Kitchen hygiene and sufficient cooking
Thaw water and packaging should be disposed of appropriately.
All kitchen utensils and surfaces, which have been in contact with the meat,
should be thoroughly cleaned.
Hands should be washed thoroughly after each
stage of preparation.
During preparation internal temperature of 74 degrees Celsius or higher must
be attained. The use of a meat thermometer is highly recommendated.
Escherichia coli
Escherichia coli is indicator of fecal pollution of drinking water supplies,
swimming beaches, foods, etc. A few strains of Escherichia coli are pathogenic
such as the strain 0157:H7 in raw hamburgers (Shiga toxin-producing
Escherichia coli (STEC) O157 ).
Reduction of E. coli O157:H7 in cattle with feed strategy
Changing grain to forage[1753]
Callaway and colleagues found that feeding cattle with large grain rations,
some starch escapes ruminal microbial degradation and passes to the hindgut
where it is fermented to sugars. EHEC can use these sugars for their grow. The
authors say that this may be the reason of E. coli O157:H7 shedding in barley
fed cattle.
Changing high grain (corn) diet to a forage diet, generic E. coli populations
declined 1000-fold within 5 d, and the ability of the faecal generic E. coli
population to survive an acid shock similar to the human gastric stomach
decreased, but this has not been observed in other studies. The authors
conclude that switching cattle from grain to forage could potentially reduce
EHEC populations in cattle prior to slaughter, but the economic impact should
be taken into consideration.
Lactobacillus acidophilus in feed to counter E.coli O157:H7
[1754]
According to Reillyl the prevention of outbreaks of E. coli O157:H7 should
begin with a proper cattle management system together with a supplementation of
cattle feed with probiotics such as Lactobacillus acidophilus as a possible
antagonist to several pathogens in the intestine.
Escherichia coli and enterococci in water
Recent epidemiological studies indicate that E.coli and enterococci show a
direct correlation with swimming-associated gastrointestinal illness rates,
while fecal coliforms do not. As the concentration of E. coli and/or
enterococci increase(s), the illness rates also increase.
These indicators are used as part of the bacterial water quality criteria and
standards to enhance the protection of human health and the environment.
Enterococci
Enterococci, which include Enterococcus faecalis and Enterococcus faecium, are
enteric bacteria used to indicate faecal contamination and the possible
presence of pathogens, in water. Total and faecal coliform bacteria currently
have been included in many water quality standards as indicators of bacterial
contamination.
Salmonella
The enteric group also includes some other intestinal pathogens of human beings
such as Shigella dysenteriae, cause of bacillary dysentery, and Salmonella
typhimurium, cause of gastroenteritis.
Typhoid fever is an acute, life-threatening febrile illness caused by the
bacterium Salmonella enterica serovar Typhi.
Old nomenclature:
Bergy`s Manual: "The names given to salmonellae do not follow the usual rules
of nomenclature
Because of their importance in pathology, the first salmonellae were given
names which indicated the disease and/or the animal from which the organism was
isolated, and names of this kind (such as S. typhy, S. paratyphy-A, S.
choleraesuis, S. typhymurium, S. abortusovis) continue to be used in clinical
bacteriology.
Scientifically, none of the present methods of nomenclature of salmonellae is
satisfactory. Nomenclature changes will be needed in order to account to new
DNA findings."
New nomenclature according to DNA findings:
The new nomenclature comprises only two species:
Salmonella enterica meaning all human
pathogens subdivided into serovars using the old genus names.
Example: Salmonella typhy = Salmonella enterica serovar Typhi, Abbreviation
S. Typhi. Salmonella enteritidis = Salmonella enterica serovar Enteritidis,
Abbreviation S.Enteritidis
Salmonella bongori: Associated with
cold-blood animals. Most of human infections are due to contact with
reptiles.
Basics of Salmonella prophylaxis: Never
eat undercooked ground beef and poultry, raw eggs, not pasteurised dairy
products. and raw shellfish.
Medical inspection of all people handling food is to be periodic repeated and
documented.
This includes clinical inspection, bacteriological examination of faeces with
regard to Salmonella bacteria, daily control of the personal to avoid purulent
wounds, persons with diarrhoea and other problems to come in contact with
food.
These persons should be transferred to areas were they cannot come in contact
with unpacked food.
Salmonellosis:
Salmonellosis ranges clinically from the common Salmonellae diarrhoea abdominal
cramps, and fever to enteric fevers such as typhoid fever caused by Salmonella
Typhi. The most common form of salmonellosis is a self-limited, uncomplicated
gastroenteritis.
Non-typhoid salmonellosis:
It is caused by any serotype of Salmonella other than Salmonella Typhi. It is
a worldwide disease of humans and animals. Animals are the main reservoir, and
the disease is usually food borne, although it can also be spread from person
to person.
Typhoid fever: ( Synonym: Enteric fever) is
caused by Salmonella Typhi.
Incubation can last up to two months. It is therefore difficult to remember the
food which might have been the source of infection. Hosts are humans, which
became carriers after an infection. Several negative microbiological tests
should be made, to let a food worker go back to his working place after a
salmonellosis.
Should this not be a demand of the local medical regulations, auditing should
try to get it listed as additional HACCP item.
Typhoid fever spread mainly from person to person via the fecal-oral route and
have no significant animal reservoirs. Asymptomatic human carriers may spread
the disease. Paratyphoid fever is caused by Salmonella paratyphi and is milder
than typhoid fever. Host are humans, which became carriers after an infection.
Typhoid Mary: Here name was Marry Mallone. She was
an Irish immigrant. She was a healthy carrier of typhoid fever. From 1900 to
1907 she worked as a cook, infecting many people.
Being caught after a long search, she was put in reclusion on North Brother
Island and released in 1910 telling her not to work as cook again. In 1915 she
was found working as cook in an Hospital infecting people there too. She was
sent back to confinement where she died in 1938.
Other carrier such as Tony Labellaand Alphonse
Cotils both handling foods remained free, being an
inconsequent attitude of the health authorities managing the epidemic in NY.
Please remember this, otherwise you will have typhoid Mary on your
suppliers-list.
The major reservoir of Salmonella is poultry
and livestock, ground meat and eggs.
Measures to reduce salmonellosis in poultry:
All animal feed should be salmonellae free. Feed was the main cause of large
distribution of Salmonella in poultry.
Slaughtering practices with reduced cross-contamination of carcasses.
Avoid cross-contamination of processed and raw food.
Training in hygienic practices for all food-handling personnel.
Cooking and refrigerating food adequately.
Radiation of poultry to reduce contamination by pathogenic bacteria, such as
Salmonella and Campylobacter. Irradiation of food is, however, not much in
use.
Shigella
Infection with Shigella is often cause of bloody diarrhoea, and stomach cramps
starting a day or two after exposure to the bacterium, usually resolving in 5
to 7 days. Some persons who are infected may have no symptoms at all and pass
the Shigella bacteria to others.
They are a menace in food production when basic hygiene, hand washing and
disinfection habits are not observed. Contaminated food is the result.
Different kinds of Shigella bacteria:
Shigella sonnei, also known as "Group D" Shigella
Shigella flexneri,Shigella flexneri or "group B" Shigella, accounts for
almost all of the rest.
Shigella dysenteriae type 1 causes deadly epidemics
in the developing world.
Shigella boydii.
Common causes of food contamination with Shigella
Infected food workers who forget to wash their hands with soap and do not use
disinfectant after using bathroom and before preparing food or beverages.
Vegetables which were contaminated with sewage.
Flies living on infected feces can contaminate food.
Drinking or swimming in contaminated water with sewage or sick person swimming
in it.
Improvements in hygiene for vegetables and fruit picking, water used to rinse
vegetable, appropriate packing may prevent shigellosis caused by contaminated
products.
Other bacteria related to food born diseases:
Listeria monocytogenes:Outbreaks in cheese and
meat.
Yersinia enterocolitica: Causes enterocolitis in
children.
Cryptosporidium parvum: Infects many herd animals
(cows, goats, sheep among domesticated animals, and deer and elk among wild
animals) and humans.
Cyclospora cayetanensis: Watery diarrhoea.
Campylobacter jejuni: It produces diarrhoea bloody
stool, fever, lasting seven to ten days. It produces a heat-labile toxin that
may cause diarrhoea.
Many chicken flocks are silently infected with Campylobacter jejuni, which can
be easily spread through a common water source or contact with infected feces.
On occasion of slaughter it can be transferred from the intestines to the meat
and giblets, especially the liver.
Not pasteurised milk can become contaminated if the cow has an infection in
her udder or the milk is contaminated with manure. Surface water and mountain
streams can become contaminated from infected feces from cows or wild birds.
It is often isolated from healthy cattle, chickens, birds and even flies. There
are pathogenic and nonpathogenic strains.
Cooking chicken, pasteurising milk, and chlorinating drinking water will avoid
the bacteria to spread.
Not pasteurised milk is therefore a possible source of bacteria such as
Campylobacter and tuberculosis. Pasteurisation time/temperature standards
should be 145F for 30 minutes (63C for 30 minutes).
Bacteria Rapid Detection Using Optical Scattering Technology [1755]
Arun K. Bhunia and colleagues developed an identification process using an
imaging approach, analysing bacterial colonies grown on solid surfaces. Using
a laser scatterometer, the system classifies scatter patterns formed by
Listeria monocytogenes colonies. Different strains and pathogenic of Listeria
can be recognised with a low error rate. It is based on Zernike moment
invariants. The detection of other pathogenic bacteria may also be included in
the system. The authors point out the feasibility of image-based biodetection
systems.
Cholera
Vibrios (which have a curved rod morphology or comma shape) are very common
bacteria in aquatic environments. Pseudomonads favour fresh water and vibrios
prefer salt water. The genus Vibrio contains an important human pathogen.
Vibrio cholerae, the cause of Asiatic cholera. Cholera
is an intestinal disease with a pathology related diarrhoeal diseases caused by
the enteric bacteria. The source of the contamination is usually the feces of
an infected person. Incubation is one to two days.
The cholera bacteria produces a toxin that inhibits the absorption of liquids
by the body. It kills because it dehydrates the body.
The disease can spread rapidly in areas with inadequate treatment of sewage and
drinking water, brackish rivers and coastal waters, raw or undercooked
shellfish from the Gulf of Mexico.
In 1991 Cholera was present in coastal areas of Peru. The disease spread
rapidly throughout Peru and into other countries in South, Central and North
America.
The Minister of Fishery of Peru wanting to restore public confidence on marine
food ate in a TV-show an undercooked fish. The day after he was hospitalised
with cholera.
Cholera is a disease associated with poverty, inadequate sanitation and low
medical care. The key to effective control is environmental sanitation.
Whenever these conditions are present in a region from where food and raw
materials are imported, auditing should keep this in mind.
Staphylococcus aureus
Staphylococcus aureus causes suppurative infections in animals and man. It
can form toxins which cause food poisoning. The contamination of food with
Staphylococcus aureus occurs due to contact with infected wounds of animals or
hands of food workers. That is why gloves are indispensable.
Contaminated fish caused intoxication with staphylotoxin which is resistant to
heat. The fish had been left for hours without cooling, the bacteria produced
the toxin which can be present in deep frozen fish and its products.
Other bacteria producing toxins: Powerful toxins are also known from
Bacillus anthracis causing Anthrax, a disease of
cattle, sheep and humans. Clostridium botulinum causes food poisoning, mainly
in low acidic foods.
Clostridium perfringens also produces an
enterotoxin and is an important cause of food poisoning and infections such as
gas gangrene. (Ernest Hemingway describes a case of gas gangrene in his book "
The snows of Kilimanjaro ").
Botulism: Many human deaths have also been attributed to the
consumption of food or water containing the toxin.
Clostridium botulinum is widely dispersed in soils. Ingestion of the organism
is not harmful. It becomes dangerous only when conditions are favourable for
its growth and subsequent toxin formation. The organism in an environment
containing decaying plant or animal organic material. Stagnant pools or damp
areas with buried decaying matter are danger areas for toxin development
Decaying carcasses are a frequent source of the toxin, as are many insects
feeding in the same tissue.
The insects may contain enough toxin to cause the disease in any bird and
chicken that ingests it. Since the toxin is water soluble, water sources may
become contaminated and provide a reservoir for the disease.Keeping the
environment clean is important to avoid botulic poisoning of birds and water
contamination.
There are different types of the toxin; types A and C cause the disease in
birds while type B frequently produces the disease in man.
Moulds
Some strains of moulds produce mycotoxins. Mycotoxins in eggs and meat is
mainly influenced by the concentration of mycotoxins in fodder. Auditing should
always look after fodder quality of breeding stations.
Bad hygienic condition during harvest, drying, transport of figs and weather
conditions such as high humidity and high temperatures are the cause of rising
mould spoilage. Consumer should look inside the figs and discard those which
are dark.
Several brands of dried figs with origin from Turkey and Greece have high
amount of aflatoxin B1,B2, G1 and G from Aspergillus flavus. The aflatoxins which are found on these samples are located in the
interior of the fruits.
As spoiled figs are detected under UV light when they are packed, only the
fruits with mould contamination from inside are not removed and are often eaten
despite a high level up to 900 microgram/kg of aflatoxin B1. (Only 2 micrograms
are allowed).
It is estimated that 25 per cent of all agricultural crops worldwide are
contaminated by molds that produce mycotoxins. The toxins are mostly found in
cereals, nuts, cocoa and coffee beans and other foods like dried fruits and
meat, particularly when the water content/activity and the temperature are
poorly controlled. The EC Scientific Committee for Food endorsed in 2004 a
provisional maximum TDI (Tolerable Daily Intake) for:
Patulin 0.4
g/kg bw/day
Ochratoxin A 5 ng/kg bw/day
Prevention and reduction of mycotoxin contamination in cereals
The complete elimination of mycotoxin such as Ochratoxin, Zearalenone,
Fumonisis and tricothecenes is not achievable at this time, according to Codex
CAC/RCP- 2003.
Good agricultural practices (GAP) represent the measures against
contamination of cereals with mycotoxins during handling, storage, processing,
and distribution of cereals for human food and animal feed.
Wheat and maize are hosts to Fusarium. A crop rotation using potato, other
vegetables, clover and alfalfa can reduce the spores of the mold in the field.
Old seed heads should be removed, destroyed or plowing under. Make soil tests
to ensure adequate soil pH and optimal fertilisation. Seed varieties
particularly resistant to molds and pests should be used.
Moisture boosts mould infections. Irrigation during flowering and during the
ripening of the normal crops, specifically wheat, barley, and rye, should,
therefore, be avoided.
If the crop is harvested with a water activity higher than 0.70, the grain must
be dried immediately to less than 14% moisture content in small grain.
Moisture levels of the crop during storage should be less than 15%. Kernels
containing symptomless infections cannot be removed by standard cleaning
methods. Seed cleaning procedures, such as gravity tables, may remove some
infected kernels.
A temperature rise of 2-3C may indicate microbial growth and/or insect
infestation in stored grains.
Intermediate storage: Buffer storage resulting from low drying
capacity should only be made when the moisture is less than 16%, the storage
time is less than 10 days, and the temperature is less than 20 C.
Organic acids, like propionic acid may be used as preservatives. These acids
are effective in killing various fungi and thus prevent the production of
mycotoxins in grains intended only for animal feed. The salts of the acids are
usually more effective for long-term storage. Care must be taken because these
compounds can negatively affect the taste and odour of the grain.
Small, shriveled grain may contain more zearalenone than healthy normal grain.
Winnowing grains at harvest or later will remove shriveled grain.
Mature grains should not remain in the field for extended periods of time,
particularly in cold, wet weather. T-2 and HT-2 toxins are not usually found in
grains at harvest, but can result from grains that are water-damaged in the
field or grains that become wet at harvest or during storage.
Candida albicans as example of microorganism which can act as
opportunists: Candida albicans can cause infections of
mouth and digestive tract by persons with weak immunological system. Yeasts
being found in food should be controlled on regard of the presence of Candida
albicans.
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
Influenza viruses: They can be divided in three types: A, B and C.
Especially the type A undergoes genetic variation. Thats 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.
[1756]
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). [1757]
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. [1757]
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.[1758]
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.[1759]
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.[1759] Nutraceuticals as preventatives of
H5N1 virus infection [1760][1761]
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.
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.
[1762]
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. [1763]
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.
[1764]
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.
[1765]
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.
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) [1767]
| 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
[1770]
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.
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.
[1768]
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.
[1769]
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.
[1771]
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.
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.
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.
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.
[1772]
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.
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. [1773]
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. [1774]
Norovirus
Norovirus should replace the designation "flu-like", "Norwalk-like","Norwalk-
and Norwalklike viruses (Caliciviruses)", "bug".
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 if these viruses are recently called Noroviruses. The are from
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.
- 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.
- Strict hand washing and use of disinfectants are very important to avoid
spreading of the virus.
- Only authorised persons should be allowed to serve food instead of
self-serving service in restaurants.
- Hotels should carefully clean bed clothes and pillow cases.
- Refrigerators and ice machines should be thawed and cleaned
periodically.
- Chlorine water solution should be used as disinfectant
- Paper towels should be used instead of textile towels.
- Sterilise hands with sterilisation solution after drying hands.
- Cutting boards and knives must be washed with hot water and soap when changing food.
- Fruits and vegetables must be washed carefully before processing.
- Meat, poultry and fish must be cooked. After maximum of 2 hours after
cooking all food must be refrigerated.
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.
[1775]
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.
[1776]
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. [1777]
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. 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.
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. [1838]
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).
- They contain only DNA or RNS
- There is no division. Reproduction occurs by only means of nucleic
acid.
- There is no growth in the extracellular latent phase.
- There are no metabolic enzymes
- 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[1417]
textbfciteHendra
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.
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.
- An icosahedron is a regular three-dimensional body with 20 triangular
faces, 12 pointed corners called vertices and 30 edges with a special symmetry
called 5:3:2 rotational symmetry:
Fivefold axis symmetry: Has the same symmetry when the particle is
rotated on-fifth of a complete rotation.
Threefold axis symmetry: The symmetry repeats every third of a
complete rotation.
Twofold axis symmetry: The symmetry repeats every half rotation.
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 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.
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:
- Enteroviruses causing diseases of the intestines, meninges, repiratory
system and heart muscle and cause poliomyelitis and infectious hepatitis
- Adenoviruses, causing diseases or the respiratory system and
conjunctiva.
- Rotaviruses, causing diarrhoea, being serious diseases of infants.
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.
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 [1405]
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.
[1365]
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.
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.
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.
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.
Although the rotavirus and the Norwalk family of viruses are the leading causes
of viral infects other viruses can also cause diarrhoea.
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.
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.
Infectious coryza: Infectious coryza
is a specific respiratory disease in chickens The disease is caused by a
bacterium known as Hemophilus gallinarum.
Pullorum Disease:It is caused by Salmonella pullorum and is primarily egg transmitted. It is also known as "bacillary white diarrhoea"
Fowl typhoid It is caused by Salmonella gallinarum. The transmission includes eggs. The poultry infections with
Salmonella gallinarum and Salmonella pullorum killed large numbers of birds and
were therefore eradicated in the 1970s. They had not cause harm in humans and
were acting as a natural vaccine against Salmonella enteritidis. The chickens'
immunity was lost and this opened the door for Salmonella enteritidis.
Fowl Cholera: It is an infectious disease of
turkeys caused by Pasteurella multocida with
watery yellowish orgreen diarrhoea.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.
Avian influenza is first of all an animal disease that requires a veterinarian
response.
The virus can be defeated and contained if countries and the international
community work closely together and set up efficient surveillance and disease
control programs. Virus outbreaks in animals need to be detected at a very
early stage, infected poultry must be slaughtered and animals at risk have to
be vaccinated. Reducing avian influenza in animals contributes directly to
protecting people's health.
Affected countries in Southeast Asia are proving that the virus can be
successfully contained. Thailand has obtained an impressive reduction of
outbreaks through massive investment in controlling the disease in poultry,
using slaughtering and improved surveillance and active disease search.
In Viet Nam, improved on-farm hygiene, farming practices, poultry movement
controls and vaccination campaigns will reduce the frequency of bird flu
outbreaks. Several countries such as Malaysia, South Korea and Japan have
eliminated the disease rapidly after the occurrence of new outbreaks.
Regrettably, most of the public discussion focuses on the human-health aspects
of bird flu, while the weak state of veterinary services in many poor countries
is being ignored. Affected countries and the international community urgently
need to invest more in support of veterinarians and animal health workers,
because they represent the first line of defence against the virus.
[1406]
A Swedish study leaded by Anna Thorson says that epidemiological data from a
rural Area in Vietnam suggest that transmission of highly pathogenic avian
influenza to humans could be more common than anticipated, though close contact
seems required.
Thorson's group found that simply having sick or dead poultry in the house did
not significantly increase the risk of flu-like illness; those people only
showed a 14 percent higher risk of flu-like illness compared to someone without
poultry. However, having direct contact with sick or dead poultry raised that
increased risk to 73 percent, Thorson said. [1407]
Vaccination in China: [1408]
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[1409]
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,
on