Ten pigs that died at a farm in Takaono, Kagoshima Prefecture, apparently succumbed to hog cholera, local officials said Tuesday.
If confirmed, it would be the first natural outbreak in Japan of hog cholera since one in Kumamoto Prefecture in 1992.
The disease, which affects only pigs and wild boars, has a fatality rate of almost 100 percent. It does not affect humans, even if meat of the infected pigs is consumed.
Kagoshima officials said that between July 20 and 23, six to seven pigs died each day at the farm, which raises about 600 pigs.
The 10 dead pigs tested positive in a preliminary test carried out by the prefectural government on the blood serum of 74 pigs that died at the farm, officials said.
The prefecture has sent specimens to the National Institute of Animal Health in Kodaira, western Tokyo, for further tests. An expert panel will confirm whether the pigs were infected, the farm ministry said.
As a preventive measure, the local government has ordered 31 pig farms within a radius of 3 km from the farm not to transfer pigs, the officials said.
Local authorities are also examining blood serum of 60 other pigs at the Takaono farm.
A suspected case of hog cholera was reported in March in Kanoya, also in Kagoshima Prefecture, and in late July authorities said pigs at another farm in the same city had come down with the disease.