Japan has confirmed its first case of the human variant of mad cow disease.
Japan's health ministry have sought to reassure the public
The Health Ministry said the unnamed man had died after contracting the fatal brain illness vCJD.
The ministry said he had probably contracted it during a month-long stay in 1990 in the UK, where the disease first surfaced in the late 1980s.
Mad cow disease (BSE) was first found in Japanese cattle in 2001. Japan has had at least 14 cases of the disease in cows, but until now no human cases.
vCJD is thought to be caused by eating beef products from cows infected with bovine spongiform encephalopathy (BSE). Tissue close to the animal's nervous system is especially dangerous.
At least 150 people have died of the disease in recent years, most of them in Britain.
The Japanese government sought to reassure the public that this was likely to be an isolated incident.
"People will not be infected with the disease in normal daily life," a health and welfare official said.
The head of the ministry panel on the disease said the man, reported to have been in his 50s, only spent a short time in the UK.
"I know that this will make many people worry, but we must take note of the fact that his stay was only one month," said Tetsuyuki Kitamoto, a Tohoku University professor.
Since BSE was first discovered in Japan, the country has screened every cow slaughtered for consumption, and the body parts at higher risk are removed.