A cow in northern Japan has tested positive for mad cow disease in a preliminary test, and its samples are being sent to university laboratories to try to confirm the infection, a state official said Wednesday.
If confirmed, it would be the nation's 18th case of the fatal brain-wasting disease, said Toshinobu Tanabe, an official in Hokkaido prefecture in charge of dairy industry.
Preliminary tests on the cow turned up positive on Tuesday at a slaughter house in Hokkaido, an island in Japan's far north, Tanabe said. But the animal's age and other details were not immediately known, he said.
Samples taken from the cow were sent Wednesday to two university laboratories in Hokkaido for more precise testing, he said. Final results from the secondary test are expected within several days.
Japan confirmed its first human case of mad cow disease in February after a man with symptoms of the illness died.
Tokyo has checked every slaughtered cow before it enters the food supply since 2001, after its first discovery of mad cow disease, known formally as bovine spongiform encephalopathy.
Japan banned U.S. beef imports after the first case of mad cow was confirmed there last December.
Under pressure from Washington, Japan's Food Safety Commission recently backed moved to relax domestic safety standards and exclude tests on cattle younger than 21 months, a step that could lead to a partial lifting of the ban. Officials still have to examine the safety of U.S. beef imports before making a final decision.
Eating beef from an infected cattle is thought to cause the fatal human variant Creutzfeldt-Jakob disease.