By Tan Ee Lyn HONG KONG, March 3 (Reuters) - Leading virologists urged governments on Saturday to curb the trade of wild birds as they can spread the H5N1 bird flu virus, which has made a comeback in many parts of the world in recent months. The warning comes as Hong Kong confirmed a scaly-breasted munia found dead in late February in the densely-populated district of Sham Shui Po had tested positive for the H5N1. It was the 13th wild bird to have been found dead with the virus in Hong Kong since the start of this year. "The munia is not a migratory bird. Again, it points to humans and the trade in movement of birds that are responsible for spreading this virus," said virologist Robert Webster from St Jude Children's Research Hospital in Memphis. Small, wild birds are bought and sold across borders and released for religious purposes in many parts of the world. The practice is particularly strong in Hong Kong, which has a huge population of Buddhists and Taoists. The city imports the small birds mostly from mainland China. "It goes back in all religions, release of birds from Noah's Ark," Webster told Reuters in Hong Kong. "It's not a Hong Kong thing or a Buddhist thing but numbers here are larger than in most places. We can't blame the birds, it comes down to the humans," he said. VIRUS RE-EMERGING The virus has re-emerged in recent months in birds in Vietnam, Myanmar, Japan, South Korea, Afghanistan, Britain and Pakistan, and killed a string of people in Indonesia. A farmer in China and a 15-year-old girl in Laos who are infected with the disease are battling for their lives. Although the virus remains a bird disease and has killed only 167 people since 2003, experts fear it may start a pandemic and kill millions if it learns to transmit efficiently among people. John Oxford, virology professor at the Royal London Hospital, said the resurgence of the virus in Asia was deeply worrying and he called on governments to hammer out contingency plans. "Without plans, there is no action. A lot of countries in southeast Asia, their plans are not substantial. That's what I find worrying. In China, there is still an attitude that it is not their problem," Oxford told Reuters in an interview. Webster said repeat sightings of the disease during the cooler months in the last few years were evidence of active reservoirs of the virus in Asia. He said the virus was probably resident all year-round in some species of ducks, which show no apparent signs of the disease. These viral loads would then build up in winter, jump to domestic chickens, which then pass them on to wild birds. Wild birds then carry the virus onward to other places. Webster urged agriculture authorities to begin surveillance of healthy-looking birds and conduct culling when necessary. "Some species of ducks are naturally more resistant to the H5N1 ... or the virus is being attenuated in the duck. The duck is the Trojan horse," said Webster, an authority on the H5N1. "There has to be surveillance of healthy looking-birds even though it is expensive. If authorities of the world put their resources into doing that, they could solve this problem."
