The National Institute of Animal Health said Thursday that since mice can be infected by the strain of bird flu virus that killed chickens in Yamaguchi and Oita prefectures, so can humans.

Also on Thursday, health officials in Tsukuba, Ibaraki Prefecture, said nine game fowl found dead along a nearby river the previous day had been incinerated before confirmation could be made on whether they, too, had succumbed to bird flu.

Referring to its recent tests on the H5N1 strain of avian flu taken from Yamaguchi chickens, the national institute said, "With mouse infection confirmed, we can't deny infection to humans."