The Japanese government confirmed another case of bird flu Monday, in a sign that authorities are having trouble stopping the virus from spreading among chicken farms.

The Miyazaki prefectural government said it completed Monday a cull of about 40,000 chickens at a poultry farm in the town of Takanabe where infection with a highly pathogenic avian influenza virus has been found.

"It's spreading quickly," said Koji Saito, spokesman for the department in charge of sanitation of livestock farming in Miyazaki Prefecture. The Japanese Times reported that the results of detailed tests on the dead birds in Takanabe confirm the season's sixth outbreak in the prefecture and the ninth in the country. Already more than 500,000 chickens have been culled in the prefecture since Jan. 22 to block the further spread of the epidemic after infections were confirmed in the cities of Miyazaki and Nobeoka as well as the towns of Shintomi, Tsuno and Kawaminami.

Wild Birds source of infection

1 Feb 2011

Experts said flu-infected wild birds were the most likely culprit, as the cases of bird flu are not concentrated in a single place, Mr. Saito said.

There have been seven cases of bird flu detected in Japan among wild birds such as swan and duck since October, six of which were confirmed as the H5N1 strain, according to the Agriculture Ministry's website.

In South Korea last week, two new cases were reported near Seoul, where 5.5 million birds at 40 locations have been culled since Dec. 31.