The United Nations food agency has called for all countries to check for bovine spongiform encephalopathy, or mad cow disease, after Canada reported a single case last month.

"The identification of a single case of BSE is not a cause for panic," Andrew Speedy, an animal health officer of the UN Food and Agriculture Organisation (FAO), was quoted by Reuters as saying.

"It is good news that odd single cases of BSE are being picked up by inspection," he said.

"There has been no sign of an escalation of numbers in any of the countries that have identified isolated cases. Rather, it demonstrates that active surveillance is picking up the one-in-a-million case.

"All countries should continue to check for the disease and apply precautionary measures, even where BSE has never been found," he added.

A handful of cases of BSE have been found since 2001 in countries such as the Czech Republic, Greece, Israel, Japan, Luxembourg, Poland, Slovakia and Slovenia, according to reports to the Office International des Epizooties (OIE).

"This is the result of effective government programmes to find and destroy the disease," Speedy said.

"In addition, the trend in the European countries which were most affected is certainly downwards. In the UK, for example, the numbers peaked in 1992 with 37,000 cases and went down to 1,144 cases in 2002," he added.

"There were less than 1,000 cases identified by the surveillance programmes in the rest of Europe in 2002, out of a total cattle population of over 80 million."

Large numbers of animals are currently tested by microscopic examination and laboratory tests. Affected animals are destroyed to ensure the infected material dies not enter the food chain, reported Reuters.