Nineteen more poultry farms in Taiwan had been found to be infected with avian influenza by Wednesday morning, bringing to 39 the total number of infected farms on the island, said agriculture authorities.

Except for two in northern Taoyuan County, all of the new additions were in southern Taiwan, including the counties of Changhua, Yunlin, Chiayi and Pingtung, and Kaohsiung City.

A total of 94,975 infected ducks and geese from the 39 farms need to be culled. The killing of 36,000 had been completed by 11 a.m. Wednesday.

The bird flu outbreak is expanding. A chicken farm in Tainan was confirmed as being affected by the virus in the afternoon; a duck farm in central Nantou county has reported abnormal deaths of poultry and testing is under way; a chicken farm in northern Miaoli County reported suspicious chicken deaths; a movement ban has been imposed on poultry.

The first case in the latest outbreak was confirmed on Jan. 9 when a chicken farm in Pingtung was found to have been hit by the H5N2 virus.

To prevent the virus from spreading, the agriculture authority has required that from Tuesday, all farms infected with the H5 strain of the bird flu virus that have seen a death rate of 20 percent or more within a span of two days will be subject to culling.