U.K. May See Future Outbreaks of Mad Cow Disease, Study Finds

By Dermot Doherty

Dec. 8 (Bloomberg) -- The U.K. may see future outbreaks of mad cow disease as new findings suggest some people develop symptoms much later than others, a study found.

Illnesses such as mad cow disease are linked to abnormal proteins in the brain, called prions, and are determined by genetic factors, according to the study, published today by The Lancet Neurology journal. Differences in a person’s DNA may mean some people are more susceptible to the lethal nerve condition or take longer to develop symptoms, researchers at the U.K. Medical Research Council Prion Unit at University College London found.

Mad cow disease, also known as bovine spongiform encephalopathy, has infected more than 200,000 cattle in the U.K. Scientists in the mid-1990s found a possible link between BSE and a new variant of the fatal human illness, Creutzfeldt-Jakob disease, or CJD, which destroys brain tissue. Evidence indicates that people may develop the disease by eating meat from infected animals or through blood transfusions.

“A second wave of CJD with a longer incubation time might hit these shores, but we do not know whether this will be a tidal wave or just an imperceptible ripple,” Hans Kretzschmar at Ludwig-Maximillians University and Thomas Illig at the Helmholtz Zentrum, both in Munich, wrote in a comment in The Lancet.

The National Creutzfeldt-Jakob Disease Surveillance Unit in Edinburgh estimates that 164 people have died from CJD in the U.K. since 1990. Early symptoms include depression or psychosis, unsteadiness and involuntary movements. By the time of death, patients become immobile and mute.

The U.K. banned eating beef from cattle aged over 30 months from 1996 until 2005, when routine, nationwide testing began. The ban cost British farmers 500 million pounds ($728 million) a year. The U.K.’s food-safety regulator, the Food Standards Agency, said in October it supports a proposal to limit tests following a drop in the number of cattle with the lethal brain- wasting disease.

To contact the reporter on this story: Dermot Doherty in Geneva at ddoherty9@bloomberg.net