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LONDON, -- Avian flu is now so widespread in poultry flocks in many countries in Southeast Asia that it is endemic, and will be very difficult to eradicate over the next decade, according to a new report from Informa, Avian Flu: The Role of Animal Health Companies in its Control and Eradication. Moreover, the report makes it clear that it will almost certainly spread to commercial poultry flocks in Europe during 2006.
"Backyard rearing of ducks is widespread in much of southeast Asia, and these flocks provide an ideal reservoir for the avian flu virus," according to the author of the report, Richard Bowles. "Many countries have also found it difficult to implement effective biosecurity measures. This is because of under-resourced state veterinary services and the nature of local farming, which in rural regions is dominated by backyard poultry reared for home consumption or sale at the local markets. It has thus proved impossible to
eradicate the disease in the poorer countries in the region, including Indonesia, Vietnam, Thailand, and China.
Consequently, the report concludes, many of these countries will find it impossible to eradiate the disease over the next decade, with backyard duck flocks acting as sources of re-infection in areas where the virus has been eradicated by culling. Avian flu is also highly likely to spread from southeast Asia, westward to Europe in 2006, with the most likely source of infection being migrating birds. The entire commercial poultry flock in Europe will be at risk, with free-range poultry being particularly vulnerable. In addition, the longer the current outbreak of avian flu in poultry continues, the greater the chances of the virus jumping the species barrier and infecting humans, thus creating a pandemic.
The main means of defense in both Europe and southeast Asia is surveillance and biosecurity, with measures taken to identify new outbreaks as soon as possible, and enforced culling of infected and 'at risk' flocks. British farmers are thus concerned that there will be a repeat of events in 2001 when large numbers of farm animals (in this case mainly cattle) were culled and burned to control and eradicate foot and mouth disease.
Vaccines against avian influenza are available, but widespread vaccination makes it difficult to confirm that the virus has been eradicated and this can lead to the loss of export markets. In most western countries the preferred method of control is complete eradication by culling. China, having failed to eradicate the virus through culling, has opted for nationwide vaccination of its poultry flock. This means that it is committed to vaccinating 14 billion birds in 2006. However, there are risks with this strategy and there are doubts about its feasibility.
"A nationwide vaccination program can lead to increased infection as the vaccination teams move from farm to farm and, in rural areas, from village to village, carrying the virus on their clothes and equipment," says Bowles. "And there are doubts about the ability of the government to complete this project due to potential shortages of trained staff and vaccine stocks. The nationwide vaccination program may develop into a more targeted regional program as the central Chinese government struggles with the logistics of vaccinating 14 billion birds a year.
Source: Animal Pharm Reports