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No Job-related Rise In Creutzfeldt-Jakob Disease

April 19, 1999

NEW YORK (Reuters Health) -- UK researchers report that individuals who work

with animals do not appear to be dying at an increased rate from

Creutzfeldt-Jakob disease, a fatal brain disorder that may be linked to

bovine spongiform encephalopathy (BSE), also known as " mad cow " disease.

From their study of the death certificates of farmers, butchers,

veterinarians and other workers who deal with BSE-infected livestock, the

authors report " no increase in deaths from Creutzfeldt-Jakob disease or other

dementias during 1979-96 among these occupational groups. "

But an expert warns in the April 17th issue of the British Medical Journal

that the disease takes up to 30 years to develop, and it may be too early to

see increased death rates.

Creutzfeldt-Jakob disease is characterized by neurological symptoms,

including dementia, hallucinations, and movement difficulties that eventually

progress to coma and death in a matter of months.

The illness is thought to be caused by infection with protein agents called

prions. Incubation of prion disorders can take years or even decades.

In their study, UK researchers led by Dr. Aylin of the Imperial College

of Medicine at St. 's, London, examined national death records from

1979-1980 and 1982-1996, focusing specifically on individuals working in

professions thought to be at highest risk for Creutzfeldt-Jakob disease --

farmers, butchers, and veterinarians.

The investigators report that " in farmers and farm workers only 12 deaths

were attributed to Creutzfeldt-Jakob disease. " No deaths linked to the

illness occurred among either butchers, abattoir workers, or veterinarians.

While five individuals working on UK farms died of Creutzfeldt-Jakob disease

during the relatively short period of 1992-1996, the researchers believe this

rise in deaths is " not higher than might be expected by chance. "

In a commentary, Dr. Annick Alperovitch of the National Institute of Health

and Medical Research in Paris, France, describes the UK findings as

" reassuring evidence " that an epidemic of Creutzfeldt-Jakob disease is not

underway.

However, she adds that " these results must be interpreted with caution "

because of general scientific uncertainty as to the incubation period of the

disease.

" Reports indicate that the incubation period may vary from 2 years to more

than 30 years, " Alperovitch points out, indicating that any rash of

infections occurring over the past few years might not be evidenced as

illness for years or even decades.

SOURCE: British Medical Journal 1999;318:1044-1045.