TAIWAN - Debate is ongoing in Taiwan on the source of the H5N8 highly pathogenic avian influenza virus that has caused such heavy losses to the poultry sector recently; one group says the authorities were too quick to identify the source as wild birds.
The Environment and Animal Society of Taiwan (EAST) has called on the Council of Agriculture to step up its efforts to identify human factors that might have contributed to the outbreak of avian flu, and not to simply blame wild birds, reports Taipei Times.
The group cited a statement by the UN’s Scientific Task Force on Avian Influenza and Wild Birds, which said that governments should not over-emphasise the role of wild birds in the introduction and spread of highly pathogenic avian influenzas.
The statement was released in December last year following the global H5N8 outbreaks, just weeks before the strain was confirmed to have hit Taiwan.
Highly pathogenic avian influenza outbreaks are most frequently associated with intensive domestic poultry production and the trade and selling of the birds, and statistics from last year showed the majority of H5N8 outbreaks worldwide originated from inside poultry farms, suggesting that wild birds that carry the strain could have been infected by poultry, the statement said.
The statement said government agencies and the poultry farming industry should recognise that focusing attention on wild birds and excluding other possible virus vectors can “misdirect critical resources away from effective disease control and result in continued spread among poultry populations, and economic losses to farmers and national income.”
Both the H5N8 strain, first detected in China in 2010, and the H5N1 strain currently in Hong Kong, were not detected among wild birds before outbreaks.
The statement continued: “It seems likely that the virus originated in poultry and has probably spilled over into wild birds then back into poultry”
The task force advised governments to determine the true source of the H5N8 virus, and to consider the possibility of transmission via the international poultry trade, and how the virus is transmitted between poultry and wild birds.
EAST chief executive, Wu Hung, said both the EU and Taiwan have come up short in finding migratory bird carcasses to support the hypothesis that migratory birds are the source of infection.
He called on the council to examine why it has not yet found a substantial number of dead migratory birds and to shift the focus of its investigation to human factors that might have caused the outbreaks.
In response, Taipei Times reports, the Bureau of Animal and Plant Health Inspection and Quarantine division head, Yang Wen-yuan, said the council arrived at the hypothesis that migratory birds were responsible for the outbreaks after meeting with domestic and international animal disease prevention experts, who said that this is the most likely cause.
Mr Yang said the effect of H5N8 is especially strong and rapid on geese and perhaps killed them before they could fly to Taiwan, which might explain why the Council has retrieved only two migratory bird carcasses that tested positive for the virus.
In addition, geese are larger in size and less likely to make long-distance migrations, which might also account for the lack of retrieved birds, he said, adding that the Council’s view on the possible cause of the outbreaks has remained unchanged.
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