TOKYO -- A cow on the northern island of Hokkaido has contracted mad cow disease, Japan's second case of the brain-rotting illness, officials said Wednesday.
Tests taken during a routine inspection of 728 animals indicated a Holsteins on Hokkaido had the fatal brain-wasting illness, said agriculture agency spokesman Hideki Arai.
Japan is the only country in Asia where the disease is confirmed to have spread, and officials have been scrambling since the first case was discovered in September to prevent a larger outbreak.
"We want people to know that this cow has not been put on the market," Prime Minister Junichiro Koizumi said. "We must prevent groundless rumors from causing concerns."
Mad cow disease, also known as bovine spongiform encephalopathy, or BSE, is believed to spread by recycling meat and bones from infected animals back into cattle feed. The illness, which has ravaged Europe's cattle industry, is thought to cause the fatal variant Creutzfeldt-Jakob sickness in humans who eat infected meat.
Japan's first case of the disease was found in a 5-year-old dairy cow. Investigators believe the cow contracted the disease by eating contaminated animal feed.
The government has since banned imports and use of feed made from recycled animal bone and meat and begun mandatory inspection before marketing.
The latest discovery of the disease comes just a month after Japanese officials had completed screening the nation's cattle herd and declared homegrown beef safe to eat.
Agriculture Ministry Tsutomu Takebe said the inspection showed that its testing procedures were effective. But domestic meat sales remain depressed, and butchers and beef restaurants are likely to struggle to win back jittery customers.