Avian or bird flu is showing signs of a resurgence, while a mutant strain – that cannot be prevented by vaccination - could be spreading in Asia, the United Nations has warned. This mutant strain appeared in Vietnam and China and its risk to humans cannot be predicted, veterinary officials said.
Virus circulation in Vietnam threatens Thailand, Malaysia and Cambodia, where eight people have died after becoming infected this year, officials warned. The World Health Organization says bird flu has killed 331 people since 2003. Bird flu upsurge has also killed or provoked the culling of more than 400m domestic poultry worldwide and caused an estimated $20bn (£12.2bn) of economic damage. Avian flu has in the past two years appeared in poultry or wild birds in countries that had been virus-free for several years: Israel and the Palestinian Territories, Bulgaria, Romania, Nepal and Mongolia are among those recently affected.
The virus had been eliminated from most of the 63 countries infected at its 2006 peak, which saw 4,000 outbreaks across the globe, but remains endemic in Bangladesh, China, Egypt, India, Indonesia and Vietnam. Number of cases has been rising again since 2008, apparently because of migratory bird movements, said the UN's Food and Agriculture Organization (FAO) chief veterinary officer, Juan Lubroth. He said, “Wild birds may introduce the virus, but people's actions in poultry production and marketing spread it.”
Mr. Lubroth added that the new strain had infected most parts of northern and central Vietnam and could also pose a risk to Japan and the Korean peninsula. South Korea began culling hundreds of thousands of chickens and ducks in December last year after confirming its first cases since 2008. The FAO is calling for countries to adopt “heightened readiness and surveillance” against a resurgence of the virus.
In people, H5N1 has caused symptoms including fever, cough, sore throat, muscle aches, eye infections, pneumonia, severe respiratory disease and, occasionally, death.