Did human remains fed to cattle cause mad cow? New theory of disease origin proposed Authors suggest BSE originated in India
HELEN BRANSWELL CANADIAN PRESS
A leading medical journal has published a disturbing theory on the origins of mad cow disease, suggesting it may have developed because human remains from the Indian subcontinent were mixed into cattle feed in Britain in the 1960s and 1970s. The authors say the practice may still be taking place elsewhere, adding it is important to discover whether other countries are importing animal byproducts contaminated with human remains that are destined for feed mills.
Canada's leading expert on transmissible spongiform encephalopathies — as mad cow and its sister diseases are called — says the unsettling hypothesis in The Lancet may be accurate.
"All I can say at this point is it's plausible. It's not out to lunch," Dr. Neil Cashman said yesterday from Vancouver, where he teaches in the department of neurology at the University of British Columbia.
"But it's also not clear whether this hypothesis is true or even if this hypothesis can be tested."
A Canadian government spokesperson said there is no evidence animal byproducts containing human remains would have found their way to this country.
"We know that we never imported bovine material — meat and bone meal — from that part of the world (the Indian subcontinent)," said Alain Charette, media relations officer with the Canadian Food Inspection Agency.
It had previously been thought that mad cow disease, or bovine spongiform encephalopathy, passed to cattle through remains of sheep infected with scrapie (the sheep equivalent of BSE) that were added to cattle feed.
The once widely held theory continued that humans who ate infected beef developed a human form of BSE. It became known as variant Creutzfeldt-Jakob disease or vCJD, to differentiate it from the classic human forms of the disease, which can occur sporadically or run in families.
But a team of British authors suggests a reverse scenario: the remains of humans infected with classic CJD were fed to cattle, which became ill with a bovine version of the human disease. The remains of those cattle would have been rendered and mixed into new batches of feed, infecting more animals. Eventually a new version of the disease passed back into humans and was dubbed vCJD.
The first case of BSE was identified in 1986 in Britain. The first human case of vCJD was diagnosed in 1995, also in that country. Britain has borne the brunt of the vCJD epidemic, with more than 150 human cases.
Authors Alan Colchester, from the University of Kent, and Nancy Colchester, from the University of Edinburgh, admitted their hypothesis is based on a compilation of circumstantial evidence.
The Colchesters noted that hundreds of thousands of tonnes of mammalian remains — whole and crushed bones and carcass parts — were imported to Britain for use in fertilizer and animal feed during the 1960s and '70s. Nearly 50 per cent was from the countries of the Indian subcontinent.
"In India and Pakistan, gathering large bones and carcasses from the land and from rivers has long been an important local trade for peasants," they pointed out.
"Collectors encounter considerable quantities of human as well as animal remains as a result of religious customs."
Hindu doctrine instructs that bodies should be cremated and the remains deposited in a river, preferably the legendary Ganges. But because of the cost of a full cremation, many corpses are partially burned, then deposited in a river.
"It stands to reason that somebody scavenging material — animal material — from the Ganges or the banks of the Ganges occasionally, accidentally or deliberately, would include human remains in their collections," Cashman said.
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