Jan 29, 2007
About 40 chickens have died on a farm in Takahashi, in Okayama prefecture.
Officials have ordered all poultry there to be culled, and the movement of people and goods restricted.
Two bird flu outbreaks earlier this month in the southern prefecture of Miyazaki have already been confirmed as the H5N1 strain of the disease.
The Japanese authorities have already determined that the new case of bird flu belongs to the virulent H5 family of the virus, but further tests are needed to find out if it is H5N1, the strain potentially deadly to humans.
Officials, however, are taking no chances. They are due to start culling all 12,000 birds at the affected Takahashi farm as early as Tuesday.
Other farms in a 10 km (six-mile) radius have been banned from transporting chickens and eggs, a ministry official told reporters.
Thousands of chickens have already been killed in Japan's main chicken-producing region of Miyazaki, following two H5N1 outbreaks in two separate towns there earlier this month.
The second case, at a farm in Hyuga, was only confirmed over the weekend.
There have been a number of H5N1 outbreaks in Japan since early 2004, but there have been no human deaths from the virus.
Health officials across Asia are on alert as a growing number of countries have reported cases in both birds and humans in recent weeks.
Since the H5N1 virus emerged in South East Asia in late 2003, it has claimed more than 150 lives around the world.
There are fears the virus could mutate to a form which could be easily passed from human to human, triggering a pandemic and potentially putting millions of lives at risk.