NIIGATA – An outbreak of bird flu is suspected in a coastal area of Niigata Prefecture, the local government said Wednesday, following the recent discovery of highly pathogenic avian flu in an inland area.

The announcement came as the country is trying to stem the spread of avian influenza, which has also affected ducks on a farm in Aomori Prefecture.

In the latest case in Niigata Prefecture, around 100 chickens died between Tuesday and Wednesday morning at a farm in Joetsu on the Sea of Japan coast, and six of those birds tested positive after preliminary analysis.

The prefectural government began culling all the 230,000 chickens on the farm Thursday without waiting for the outcome of further tests, based on the request of the farm ministry.

The Niigata government is also in the process of culling approximately 310,000 chickens at a poultry farm in Sekikawa — about 140 km from Joetsu — after announcing Tuesday that tests had confirmed the presence of the highly virulent H5 strain of the bird flu virus.

In Aomori, around 18,000 ducks have been culled at a farm where ducks tested positive for the H5 bird flu strain. Prefectural officials and construction company workers are burying them.

These are the first cases of infection in domestic poultry since January 2015, when bird flu was detected in Okayama and Saga prefectures.

Farm minister Yuji Yamamoto called for further steps to prevent bird flu from spreading, saying in a government meeting Wednesday that “the initial response is important.”