"Our concern is that there are countries out there which may be developing BSE (bovine spongiform encephalopathy) and are not doing anything about it," said Dr Maura Ricketts, of WHO's animal and food-related public health risks division.

BSE was first detected in Britain in the mid-1980s and has since spread to a number of mainly European countries.

Some 130 people, most of them Britons, have died from what is believed to be a human variation of the brain-wasting disease after presumably eating infected meat, triggering global alarm.

The WHO official, presenting a report on the BSE threat, said contaminated meat and bone meal animal feed were known to have been exported to a number of countries where few or no cases of the fatal disease had yet been reported.

Far from being a cause for concern, the reporting of cases could be a reassuring sign the authorities were taking steps to detect infection and to eradicate the problem, she said.

"Central and eastern European countries as a whole were large importers of this material. Slovakia, Slovenia and the Czech Republic have reported cases but other countries need to be checking this," she added.

Southeast Asia, along with parts of North Africa, were other areas where significant amounts of contaminated feed had been imported from Western Europe, she said.

RECYCLING FEED

All cases of BSE have been traced to imports of animal feed or cattle from Britain, or later from the European Union.

After peaking at around 40,000 cases in 1993, the incidence of BSE in Britain declined sharply to little over 1,200 in 2001, although this was still more than the total number recorded in the rest of the world that year.

Ricketts said there was still much to learn about BSE and its human form, variant Creutzfeldt-Jakob disease, including the maximum incubation period in humans. There had been fears that the human fatalities could soar if the incubation period was very long.

"As time goes on, I do not think many people are predicting huge epidemics anymore," she said.

BSE was clearly linked to the recycling of cattle carcasses to recover meat and bone meal protein which was then fed back to other cattle, WHO said.

The European Union and other countries have banned the use of such feed for cattle and taken numerous other measures including strict slaughterhouse regulations.

The east European and richer Asian countries were of particular concern because they were states which had already developed, or had the potential to develop, their own industries using cattle waste material - anything not eaten by humans - and recycling it as animal feed.

The WHO report - 'Understanding the BSE Threat' - is intended as an alarm call to governments about what actions they should be taking as well as providing consumers with information about the risks posed by contaminated meat.