A highly pathogenic strain of bird flu has been found in Yasugi, Shimane Prefecture, the Environment Ministry said on Friday.
The H5N8 subtype was detected in two samples of droppings from migratory Bewick’s swans that were collected Nov. 3, the ministry said.
While investigating the infection route, the ministry has designated 10 km around the spot as an intensive wild bird monitoring area.
The Shimane Prefectural Government is warning local poultry farms to take infection prevention measures.
Officials said that so far no dead wild birds have been found that appear to have had the disease.
Ministry officials said birds infected with the virus abroad must have flown to Japan to pass the winter, since most Bewick’s swans seen in the country migrate from Arctic areas.
Meanwhile, Tottori Prefecture, which lies close to Yasugi, held a meeting on Thursday evening to encourage the monitoring of deceased wild birds and to provide information to residents.
It is the first time bird flu has been found in wild bird droppings since a case involving a wild duck in Wakkanai, Hokkaido, in 2010, according to the Environment Ministry.
The H5N8 subtype is the same virus strain of bird flu that has spread in South Korea starting in January and was also detected at a poultry farm in Kumamoto Prefecture in April, ministry officials said.
Chickens at a farm in Yasugi were infected with the highly pathogenic H5N1 subtype in November 2010.