The other two outbreaks occurred in the Miyazaki prefecture.

The 12,000 birds on the farm, which is near the city of Takahashi, are to be culled. Inspectors found no other cases at 15 poultry farms within a 10-kilometer radius of the farm but said they had restricted movement of goods in the area to help prevent spread of the virus.

The first outbreak of bird flu was reported in Japan in the Yamaguchi prefecture on the island of Honshu in 2004. The disease, which has decimated poultry flocks in Asia, Europe, the Middle East and Africa, can be transmitted to humans who come in contact with sick birds and is often fatal.

Of the 269 reported human infections worldwide, there have been 163 deaths, according to the World Health Organization. No H5N1 deaths have been recorded in Japan.

Health officials fear that the H5N1 virus could mutate into a form easily transmissible from one person to another, sparking a global pandemic that could take millions of lives.