A research institute that analyzed the highly pathogenic bird flu virus detected in northern Japan in October says it is the same type as one found in the country during the previous two seasons from autumn to spring.

This season's first case was found last month in a dead wild crow in Bibai City in the prefecture of Hokkaido.

The National Agriculture and Food Research Organization says its genome analysis showed the H5N1 strain of the virus was of the same genotype as one of the viruses detected in the country in 2021 and 2022 seasons.

The organization says it has found no genetic mutations that could make the virus more contagious to mammals, and that it is unlikely that humans will be infected.

A series of bird flu outbreaks hit poultry farms and other facilities across Japan last season. The number of chickens and other birds culled reached a record high.

A group leader at the organization, Uchida Yuko, said the detection of the same type of virus as the last seasons indicates possible sustained infections among migratory birds.

Uchida urged poultry farms and other facilities to be on the alert for the virus, as it has already been detected in Japan.