Epidemiology professor Roy Anderson of the Spongiform Encephalopathy Advisory Committee said current tests for the disease urgently needed to be checked and warned that unreliable tests on cattle in the early stages of the disease may mean infected animals are being missed.
"I have a horrible feeling that there is an underestimate of the figures in Europe," he told the House of Commons' select committee on environment, food and rural affairs.
Mad cow disease, known as bovine spongiform encephalopathy, or BSE, emerged in 1986 and developed into an epidemic when farmers added recycled meat and bone meal from infected cows into cattle feed.
The government announced in 1996 that the cattle illness could infect humans. It is thought to cause variant Creutzfeldt-Jakob Disease in humans who eat meat from infected animals.
There have been 178,378 cases of BSE since 1986 on 35,253 farms in the United Kingdom. At the height of the epidemic, there were 30,000 cases a year, leading to widespread destruction of cattle herds and a crisis for the British beef industry.
The Department for the Environment, Food and Rural Affairs said Wednesday there had been 572 cases in cows so far this year, through Oct. 19, which it said clearly indicated that the country was at the tail end of the disease.
Anderson said that tests on cattle that were in the late stages of incubation - around five years - were accurate. But he questioned the accuracy of tests on brain material in the early stages of incubation - around one year.
"I want to know what the sensitivity of this test is by the stage of incubation of the animal," he told lawmakers. He also said vets should be given automatic powers to go on to farms and conduct random tests for BSE or other diseases such as foot-and-mouth.
A scientific study that suggested BSE had spread to sheep was scrapped last month, because researchers were testing the wrong brains, causing much embarrassment for the government.
Scientists who thought they were testing sheep brains were actually working with tissue from cattle, the government said. The five-year study had cost $315,000 and was supposed to involve 2,860 brains from sheep. However, samples were incorrectly labeled, and only 480 reliable tests were conducted
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