Mad Cow Agent

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Headline: Nothing yet totally kills mad cow agent - expert

Wire Service: RTna (Reuters North America)

Date: Wed, Dec 9, 1998

Copyright 1998 Reuters Ltd. All rights reserved.

The following news report may not be republished or redistributed, in whole

or in part, without the prior written consent of Reuters Ltd.

By Maggie Fox, Health and Science Correspondent

WASHINGTON (Reuters) - Nothing has yet been found that completely

kills off the agents that cause mad cow disease and related diseases in

humans, a U.S. researcher said Wednesday.

Speaking at a science meeting, Dr. Asher urged more research to

find some method that will make food processing, medical and other

equipment safe from carrying infection by the agents that cause such

diseases.

Mad cow disease, known officially as bovine spongiform encephalopathy

(BSE), is caused by a mutated protein known as a prion. So are related

diseases such as Creutzfeldt-Jakob disease (CJD), which affects people, and

scrapie in sheep.

Britain is at the tail end of an epidemic of BSE, believed to have

been caused by feeding the remains of sheep infected with scrapie to

cattle. A human version of the disease, known as new variant CJD or nvCJD,

has killed 30 people so far.

Scientists think BSE is only transmitted by eating infected products.

Europe only last month lifted a 32-month ban of British beef products.

But CJD is known to have been transmitted by transplants of infected

brain matter and it is possible infection could be passed by using

contaminated instruments.

Asher said he set up a laboratory last year at the Food and Drug

Administration (FDA) to look for ways to eliminate the infectious prions.

But he told a science meeting organized by the FDA and the American

Association of Pharmaceutical Scientists, it is hard to kill them.

The standard disinfectants -- sodium hydroxide, sodium hypochloride

and moist heat -- had all eliminated most of the infectivity but not all of

it.

" Our goal is to kill it all, " he said.

Other scientists have found that heating infected material to high

temperatures for long periods of time, pouring on strong disinfectants and

leaving them to dry out all fail to kill off all the infectivity.

Asher says efforts to find a way to destroy the agent have fizzled out

somewhat. " This is a very undersubscribed field of effort, " he said.

Maybe a cocktail of disinfectants will work, he said. " It just appears

to me that attention should be paid to using a combination of treatments, "

he said.

Luckily, Asher said, there is no evidence that any cattle in the

United States have succumbed. He said tests of brains from 7,000 animals

show no sign of BSE. Many of the cattle tested had fallen down for no

explained reason -- one of the same symptoms of BSE.

BSE and CJD both gradually destroy the brain. Victims lose the ability

to walk or stand, become demented and die. There is no treatment or cure.

REUTERS