U.S.expert says bird flu virus may have dangerous mutations

Recent cases of bird flu outbreak indicate the H5N1 avian influenza virus may have dangerous mutations, a U.S. bird flu expert said on Tuesday.

The virus, which has killed several domestic cats in Germany and Austria, may have acquired the ability of directly transferring from wild birds to cats and dogs, said Dr. Carol Cardona, a poultry veterinarian and professor at the University of California, Davis.

Cardona is part of a network of U.S. researchers providing education about bird flu. Her laboratory also conducts research on avian influenza viruses focusing on the disease caused in chickens.

"Recent cases in Germany and Austria may be a dangerous sign," Cardona told Xinhua in a telephone interview.

"We have known that felids could be infected by the virus easily," she said. "Last year, tigers and leopards in a zoo in Thailand were killed by the virus after eating fresh chicken, but the German cases are different."

Generally, the H5N1 virus transfers from wild birds to poultry, and then goes from poultry to wild birds or other species, including human, according to Cardona.

But in recent cases, domestic cats were infected after eating dead wild birds or contacting with them.

"That means, the virus may have acquired the ability of directly transferring from wild birds to other species, such as domestic cats or urban dogs," she said. "It may be able to do this without the poultry."

If the virus can infect domestic cats and urban dogs, which closely contact with people in everyday life, it will pose more threat to humans, she said.

There is no evidence that the virus has accomplished the so-called "species jumping," which means it can circulate among animals other than the birds.

"But there is the possibility, so we can never underestimate the virus," she said. [my emphasis]