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Experts issue warning over bird flu resurgence

New strain of avian flu in and beyond Asia prompts UN warning

Adrian O'Dowd

Tuesday, 30 August 2011

Experts are calling on countries to heighten their preparations and surveillance against avian flu following a new mutant strain detected in Asia. 

The United Nations Food and Agriculture Organization (FAO) today issued a warning about a possible major resurgence of the H5N1 highly pathogenic avian influenza. 

The FAO said there were signs that a mutant strain of the deadly bird flu virus was spreading in Asia and beyond and there were unpredictable risks to human health. 

Since it first appeared in 2003, the H5N1 virus has infected 565 people, 331 of whom died, according to World Health Organization figures. The latest death occurred earlier this month in Cambodia, which has registered eight cases of human infection this year, all fatal.  

In addition, the virus has killed or forced the culling of more than 400 million domestic poultry and caused an estimated $20 billion of economic damage across the globe before it was eliminated from most of the 63 countries infected at its peak in 2006.

The FAO said that the virus remained endemic in six nations and although the number of outbreaks in domestic poultry and wild bird populations shrank steadily from an annual peak of 4,000 to just 302 in mid 2008, outbreaks have risen progressively since, with almost 800 cases recorded in 2010-2011.  

Since 2008, the virus has expanded geographically.

The advance in the virus seems to be associated with migratory bird movements, according to FAO chief veterinary officer Juan Lubroth, who said migrations helped the virus travel over long distances.

Mr Lubroth said: “Wild birds may introduce the virus, but peoples' actions in poultry production and marketing spread it.” 

Recently affected areas include Israel and the Palestinian Territories, Bulgaria, Romania, Nepal and Mongolia. 

A further cause for concern, added Mr Lubroth, was the appearance in China and Vietnam of a variant virus apparently able to resist the defences provided by existing vaccines. 

In Vietnam, which suspended its springtime poultry vaccination campaign this year, most of the northern and central parts of the country – where H5N1 is endemic – have been invaded by the new virus strain, known as H5N1 - 2.3.2.1. 

The FAO said Vietnam's veterinary services were on high alert and were considering a targeted vaccination campaign in the autumn. 

“The general departure from the progressive decline observed in 2004-2008 could mean that there will be a flare-up of H5N1 this fall and winter, with people unexpectedly finding the virus in their backyard,” said Mr Lubroth.  

The countries where H5N1 was still present – Bangladesh, China, Egypt, India, Indonesia and Vietnam – were likely to face the biggest problems, he said, but added that no country could consider itself safe.

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