Bird flu has jumped to new species in Asia, killing three house cats and infecting a white tiger in Thailand, officials said Friday.

The pet cats in Nakhon Pathom province (search) outside Bangkok are the first domesticated mammals known to have contracted the disease in the current outbreak.

Thai veterinarian Dr. Teeraphon Sirinaruemit also said a white tiger at Khao Khiew zoo (search) near Bangkok was found to have the virus, but it has since recovered and is in good health. The zoo is the same where a clouded leopard died of bid flu last month, the first mammal apart from humans known to have died from the virus this year.

The developments came as the head of the U.N. Food and Agriculture Organization (search) urged international cooperation in fighting the disease, warning it could spread to more animals.

The virus has killed at least 22 people in Thailand and Vietnam, while infecting birds in 10 Asian nations. A World Health Organization (search) official said it's possible that Indonesia could have human cases despite government claims to the contrary.

"It's such a large country and such a large population ... it may have been diagnosed as ordinary pneumonia," the WHO official, Georg Petersen, said.

The infection of three cats in Thailand has raised fears that the disease could spread from pets to humans, WHO virus expert Dr. Prasert Thongcharoen said.

So far, cases in people have been traced largely to direct contact with infected chickens, other birds and their waste.

Health experts are concerned about the bird flu sickening other animals, in part because that could prompt mutations in the virus that in turn could make it easier to pass among people. That concern holds especially for pigs because of their genetic similarities to humans.

"It's quite a serious problem," FAO Director General Jacques Diouf said. "Unless we deal with it very seriously, there is the risk not only of other birds contracting it but also other animals, and naturally we have also seen the effect on humans. That's why it is necessary that we cooperate together in the region."

Canadian officials are testing samples of a mild bird flu virus that has been detected and isolated on a British Columbia farm, Canadian Health Minister Pierre Pettigrew said.

Dr. Danuta Skowronski of the British Columbia Center for Disease Control said the outbreak of the H-7 avian flu is "certainly not" the same version of the virus that has hit poultry stocks and killed people in Asia, which is known as the H5N1.

News of the British Columbia outbreak prompted Japan and Hong Kong to immediately place temporary bans on the imports of poultry products from there, officials said.

Officials in Delaware and New Jersey also are tackling an outbreak of H-7 in poultry. That version of the virus does not typically infect humans, according to the Centers for Disease Control and Prevention.