Avian influenza (AI) is a contagious viral infection, which can affect several species of food producing birds (chickens, turkeys, quails, guinea fowl), as well as pet birds and wild birds including waterfowl.
When classifying AI viruses there are two categories: low pathogenic (LPAI) and high pathogenic (HPAI)forms. The determining factor in deciding, whether the virus is classified as LPAI or HPAI, is based upon the severity of the illness that is caused in birds, for example, AI causes the greatest number of deaths in birds.
Most AI viruses are low pathogenic. LPAI forms will usually cause little or no clinical signs in infected birds. It is possible that some low pathogenic viruses are capable of mutating into high pathogenic viruses. This is the situation that causes the greatest concern for farmers and food safety officials, the mutation from LPAI to HPAI.
There are many influenza subtypes, two of which include H5 and H7. Historically, only the H5 and H7 subtypes are known to have become highly pathogenic in avian species.
Possible contributing factors:
The mitigating factor here may be one of scale and the conditions within which the chickens are kept. "The bird flu epidemic raging through Asia is symptomatic of a sick, unsustainable process by which we produce our food," stresses Dr. Meriel Watts, coordinator of PAN Aotearoa/New Zealand. "Cramming tens of thousands of birds into cramped sheds is not only cruel and inhumane, it is a human health disaster in waiting. Because of the stressful and unhygienic way in which these birds are kept, they have to be force fed antibiotics to manage the diseases that can so easily run rampant. The result is lowered levels of disease resistance, and increased risk to human health through resistance to antibiotics."
http://www.croceviaterra.it/contadini/av...
What is recommended:
Biosecurity.
The term biosecurity is becoming well-used in the media due to the recent incidences of mad cow disease and avian flu. Biosecurity refers to the safety of live things. In the case of avian flu, biosecurity means protecting poultry flocks from being exposed to the virus.
Poultry operations of all kinds have become more and more sophisticated. The problem may well be one of scale with giant operations keeping birds in cages in very tight quarters so closely packed, that a virus can readily sweep through the flock. Large scale factory farms are dominant in the industry. As they become more technically efficient, however, they also become a threat to themselves and their neighbours because of their large size and the concentration of many birds in one space. Disaster can strike anytime unless vigilance is constant.
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