By Tan Ee Lyn SINGAPORE, Dec 11 (Reuters) - Poultry farms must be properly screened and protected from small birds such as sparrows, starlings and pigeons which are capable of passing the H5N1 bird flu virus to chickens, an expert said on Monday. These small birds are resident in many countries and small numbers of them have been found infected in recent years with the H5N1 virus. Leading virologist Robert Webster told Reuters his laboratory infected sparrows, starlings and pigeons with strains of the H5N1 virus isolated in Vietnam, Thailand and Hong Kong recently. His team confirmed the birds shed the virus in their stools and can therefore infect poultry. "They were infected and shedding the virus in their faeces and from their respiratory tracts. The sparrows died, so they are not as big a threat," Webster said on the sidelines of a conference on avian flu and other infectious diseases in Singapore. "The bigger threats are the starling and the pigeon. The starling didn't die, but shed plenty of virus," said Webster of the St Jude Children's Research Hospital in the United States. The virus replicated very well in the starling and less well in the pigeon, he added. Although all three species did not transmit the virus to their own kind, the fact that the infected starlings and pigeons did not succumb to the virus meant they could be dangerous to poultry. "This means that you've got to keep these small birds out of chicken houses, too, because they can be infected and they can carry the virus from this chicken house to that chicken house," Webster said. The H5N1 virus remains largely a bird disease and does not infect people easily. However, it has killed 154 people since 2003 and experts fear it might trigger a pandemic if it learns to transmit easily among people. Experts have long urged countries such as China and Indonesia to enforce stronger surveillance on poultry and to get rid of the virus in chickens and domestic ducks because they are seen as major agents in transmitting the virus to people. Most of the 258 people infected with H5N1 since 2003 are believed to have contracted the disease from chickens. They kept chickens in their backyards and many were believed to have handled sick and dead chickens before falling ill themselves.(Editing by David Fogarty; World Desk Singapore +65 6870 3813)
