The outbreak of foot-and-mouth disease in Britain will be especially hard to contain as it is a new and especially virulent strain of the virus, New Scientistmagazine reports.
The virus, called "the Pan-Asian topotype", was first discovered in India in 1990, raced westwards through the Arabian peninsula, where it is now endemic and reached Europe in 1996, the British science weekly says.
It also travelled eastwards, hitting Mongolia and countries that had been free of the disease for a long time, such as South Korea and Japan as well as South Africa.
"There are probably many more countries that are affected, but haven't bothered to report it," said Mr Alex Donaldson, head of the Institute for Animal Health at Pirbright, Surrey, a leading lab researching foot-and-mouth.
The Pan-Asian type, a variant of the virus's O strain, is particularly worrying because it can infect an unusually large range of hoofed animals, even rare Asiatic camels, researchers believe.
The virus spreads from burst blisters on the animal's hoof or mouth. The Pan-Asian type is so infectious that as few as 10 viruses are enough to infect a cow, New Scientistsaid.
The British outbreak, which has triggered a scare across continental Europe, began at a pig-fattening farm in north-eastern England.
Mr Donaldson said a suspected source could have been contaminated swill - waste food from hotels and restaurants - that could have come from East Asia but had not been heat-treated to kill the virus.
AFP