Nov 4, 2005 (CIDRAP News) – About 9,000 chickens have died and close to 370,000 have been culled in China in the largest of several outbreaks of H5N1 avian influenza reported this week in Asia.

Several small avian flu outbreaks have been reported in Thailand and Vietnam, while Japan reported another H5 outbreak in poultry. In addition, an H5 virus was found in some healthy wild ducks in British Columbia, but authorities were confident it was not an H5N1 strain.

In a report to the World Organization for Animal Health (OIE) yesterday, Chinese authorities said 8,940 chickens, plus 20 magpies and other wild birds, had died of H5N1 infection in the northeastern province of Liaoning, which borders North Korea.

The outbreak triggered the culling of 369,900 more birds within 3 kilometers of the site and the vaccination of another 13.9 million, the report says. An Agence France-Presse (AFP) report said the virus struck farms in six villages.

The outbreak was China"e;s fourth since Oct 19, according to AFP. The other recent outbreaks were in the Inner Mongolia region and in Anhui and Hunan provinces in central China. The country has had no confirmed human cases of H5N1.

In Thailand, about 1,700 chickens, broiler ducks, and fighting cocks died in five small outbreaks in two provinces, according to a report authorities filed with the OIE Nov 1. The report listed the disease as highly pathogenic avian flu but did not specify the viral strain. However, Thailand has reported many small H5N1 outbreaks in poultry since a nationwide surveillance program was launched in July.

Japanese authorities reported plans to kill 180,000 chickens after finding signs of avian flu on one farm, according to AFP and Associated Press (AP) reports today. The AP said antibodies to H5 viruses had been found in some of the chickens.

The reports conflicted on the location. AFP reported that the outbreak was in Ibaraki prefecture near Tokyo, where a number of H5N2 outbreaks have been reported in recent months, but the AP said the outbreak occurred on "a northern farm."

Vietnam has confirmed avian flu outbreaks in three northern villages, according to another AP report today. The story quoted a local official as saying that more than 3,000 poultry died or were destroyed in Bac Giang province.

In Canada, about 174 wild ducks out of more than 700 sampled in central British Columbia tested positive for an H5 virus, according to a Nov 1 Canadian Press (CP) report. The report came a day after the announcement that an H5 virus had been found in 28 ducks in Quebec and five in Manitoba.

Dr. Ron Lewis, British Columbia"e;s chief veterinarian, said it was "very unlikely" that the H5 virus found in the ducks was the same as the H5N1 strain in Asia, according to an AFP report.

He said the samples all came from young, healthy birds. Fourteen of the samples tested strongly positive, and another 75 were weakly positive, the CP report said. The birds tested were from the Merritt area in south-central British Columbia.

The testing was part of a "cross-country" search for viruses carried by wild waterfowl, AFP reported. Lewis said this type of surveillance had not been done before, so authorities didn"e;t know if the finding should be considered unusual or not, according to the CP.

In other news:

• Croatian authorities reported Nov 2 that a swan that had been shot last week tested positive for H5N1, AFP reported. The swan, which had been tagged in Hungary, was shot in the village of Zdenci, where other swans had tested positive for the virus recently.
• In Macedonia, tests ruled out avian flu in one of about 1,000 chickens and turkeys that were found dead in mid October, according to AFP. A veterinary official said the tests showed the country is free of avian flu.