Countries across Asia have moved swiftly to block American beef exports after the United States reported its first suspected case of mad cow disease. From Tokyo to Seoul to Singapore, governments suspended U.S. beef imports Wednesday amid a mad cow scare that could eventually cost the United States beef industry billions of dollars.

The suspensions come one day after a cow in the U.S. state of Washington tested positive for the disease. This is the first time it has appeared in the United States, the world's second largest beef exporter after Australia. A sample from the sick cow is being sent to Britain for confirmation of the disease and the results are expected in three to five days.

But some Asian countries did not wait for those final results, and temporarily banned U.S. beef exports within hours of the U.S. announcement. Japan and South Korea, which together spent more than $2 billion on U.S. beef in 2003, say they will extend their bans indefinitely if the U.S. case of mad cow disease is confirmed.

At the same time, Japanese Health Minister Chikara Sakaguchi tried to calm public fears. He says Japanese authorities will not distribute already-imported U.S. beef on the domestic market.

There have already been eight confirmed cases of mad cow disease in Japan - the first Asian country to be hit. The initial outbreak, in September 2001, sent beef consumption plunging, but beef sales have slowly recovered.

One Japanese shopper says she has already cut back on eating beef so the latest news from Washington State does not affect her lifestyle. A butcher says he was expecting that more beef would sell as the end of the year approaches but he predicts it is going to be difficult.

Singapore's government said Wednesday that if the suspected U.S. case of mad cow disease is confirmed, it will not import American beef until the country certifies it has been free of the illness for six years.

Australia, Malaysia, Thailand and Taiwan have also slapped bans on U.S. beef.

The medical name for mad cow disease is bovine spongiform encephalopathy. Scientists have linked eating beef infected with BSE to a human variant of the disease, which destroys brain tissue. It has killed more than 130 people, most of them in Britain.