Consumers responded calmly Wednesday to news of the first outbreak of avian flu in Japan since 1925.

The outbreak, confirmed Tuesday, has prompted concerns among health officials that the virus may mutate and affect humans. The news comes less than a month after Japan placed an import ban on U.S. beef following the Dec. 24 discovery of a case of mad cow disease there.

Poultry sales have been largely unaffected by the outbreak, in sharp contrast to the panic created in September 2001 when the discovery of the first case of mad cow disease in Japan caused beef consumption to nosedive. Mad cow disease is formally known as bovine spongiform encephalopathy.