Masataka Tangiku, an Agriculture Ministry veterinarian, said the National Institute of Animal Health tested tissue from the seven pet chickens and found them positive for the virus.

The outbreak of avian flu has killed 22 people in Vietnam and Thailand. No human cases have been confirmed in Japan.

An outbreak last month at a farm in Yamaguchi Prefecture killed thousands of chickens, the country's first case of bird flu in 79 years.

Agricultural officials declared the Yamaguchi farm safe Feb. 18 and it resumed shipments of poultry and eggs.

However, scientists at the National Institute of Animal Health determined that the Yamaguchi strain fatally infected mice in lab tests, an institute official said on condition of anonymity Feb. 19. It was the first time researchers had shown the Yamaguchi strain -- believed to be the milder H5 strain -- could infect mammals.

No link between the two outbreaks in Japan has been found.

The Japan Times Weekly: Feb. 28, 2004
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