First North American Dies from Mad Cow Disease
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Source: ENS.
First North American Dies from Mad Cow Disease
SASKATOON, Saskatchewan, August 8, 2002 (ENS) - A confirmed case of variant Creutzfeldt-Jakob disease (vCJD) in Saskatchewan, the first in North America, does not present a threat to the general public or the Canadian food supply, provincial health officials hastened to assure the public.
Final confirmation was received this week that a Saskatchewan resident who died early this summer, had vCJD, a rare and incurable neurological disease.
Variant Creutzfeldt-Jakob disease has been linked to the consumption of beef products from cattle infected with bovine spongiform encephalopathy (BSE), also known as mad cow disease. Evidence to date indicates that there has never been a case transmitted from person to person.
Laboratory tests were performed in Canada and the United Kingdom. Dr. Ross Findlater, Saskatchewan chief medical health officer, said the disease was likely acquired in the United Kingdom, where the deceased lived and visited during the 1980s and 1990s.
Dr. Steven Whitehead, deputy medical health officer of the Regional Health Authority for the Saskatoon area, said that, for privacy reasons, the identity of the deceased will not be disclosed. Family members have indicated they do not wish to be contacted by members of the media.
Of the 125 vCJD deaths worldwide, almost all had multiple year exposures in the United Kingdom between 1980 and 1996 during the occurrence of a large UK outbreak of BSE among cattle. The current risk of being exposed to BSE as a traveler in Europe is extremely small, say health officials in Canada and the United States.
Findlater said Canada has been free of BSE except for a single case in 1993 in a cow imported from the United Kingdom, which was destroyed.
"It is highly unlikely that the case originated in Canada and just as unlikely that it was passed on to anyone in Canada," said Findlater.
"Based on our current knowledge of this case, there is no reason to believe it is connected to Canadian livestock or the Canadian food supply," he said.
Findlater noted that the first case in the United States, announced in April 2002, similarly involved an individual who died in that country after acquiring vCJD in the United Kingdom.
Dr. Whitehead said there are no known cases of vCJD being transmitted from person to person.
While there is a theoretical risk of transferring vCJD through the blood system, the deceased was not a blood donor.
Whitehead said there is a theoretical risk that the disease could be spread by medical equipment – even after it has been thoroughly disinfected. So out of an abundance of caution, the Saskatoon Regional Health Authority is contacting 71 people who may have been exposed to the same piece of equipment as the deceased while at the hospital.
"The chances of vCJD being spread by a piece of medical equipment is extremely minute," said Whitehead. "However, as long as there is even a theoretical risk, we believe we have an ethical obligation to inform the patients as they have a right to know. Many of these patients have already been contacted and we expect to reach the others in the next few days."
Whitehead said a final diagnosis of vCJD can only take place after death, by performing laboratory tests on brain tissue. He said initial testing was performed at the University of Toronto and final diagnosis was provided earlier this week by leading vCJD experts in the United Kingdom.
Until this year, North American had been free of vCJD. But in April, the Florida Department of Health and the Centers for Disease Control began investigating a likely case of vCJD in a 22 year old citizen of the United Kingdom living in Florida. If confirmed, this would be the first case of vCJD reported in a U.S.resident. But confirmation of a vCJD diagnosis can only be obtained through study of brain tissue obtained by a brain biopsy or at autopsy.
A second type of CJD, known as classical Creutzfeldt-Jakob disease (CJD), occurs naturally in the population at a rate of one person in a million per year. Classical CJD is not linked to the consumption of beef products.
A similar contagious fatal neurological disease in deer and elk, known as chronic wasting disease, was the subject of a two day symposium that drew 450 wildlife experts from the United States and Canada to Denver, Colorado Tuesday and Wednesday.
Chronic wasting disease is classified as a transmissible spongiform encephalopathy (TSE), and is similar to mad cow disease in cattle and scrapie in sheep.
Once found only near Fort Collins, Colorado, outbreaks of chronic wasting disease have been found in the past two years in Colorado and Nebraska, as well as in wild deer in New Mexico, South Dakota, Wisconsin and Saskatchewan. The disease has been diagnosed in commercial game farms in Colorado, Nebraska, South Dakota, Montana, Oklahoma, Kansas, Saskatchewan and Alberta.
Infectious agents of all TSEs are neither bacteria nor viruses, but are thought to be prions - infectious proteins without associated nucleic acids.
Although chronic wasting disease is a contagious and fatal among deer and elk, research suggests that humans, cattle and other domestic livestock are resistant to natural transmission. Researchers do not know how the disease spreads among animals in either the wild or in captivity, nor do they understand how to control it.
While the possibility of human infection remains a concern, there have been no verified cases of humans contracting chronic wasting disease.
Scientists at the symposium did not report any cases of chronic wasting disease transmission to humans or to cattle.
Elizabeth Williams, professor of veterinary science at the University of Wyoming and an expert in chronic wasting disease, told symposium delegates that no evidence of transmission to cattle has been reported.
But medical experts in Wisconsin suspect that chronic wasting disease may have been transmitted to humans. Scientists are investigating the deaths of three friends who ate elk and deer meat at wild game feasts hosted by one of them near Superior, Wisconsin in the 1980s and '90s. All three died in the 1990s.
Scientists from the Wisconsin Division of Health and the Centers for Disease Control (CDC) are reviewing autopsy results of the three men, two of whom died of Creutzfeldt-Jakob disease, their families told reporters. The other died of a more common brain disease.
Four or five cases of CJD are diagnosed in Wisconsin each year. But state health officials are concerned about the connection between these deaths and the wild game the three men consumed.
CDC researcher Dr. Ermias Belay told symposium delegates that "there is no strong evidence between chronic wasting disease and Creutzfeld-Jakob's disease."
Belay advised continued surveillance to monitor the possible transmission of chronic wasting disease to humans.
For more information about Creutzfeldt-Jakob disease in the UK log on to: http://www.cjd.ed.ac.uk/.
Learn more about chronic wasting disease from the U.S. Department of Agriculture Animal and Plant Health Inspection Service at: http://www.aphis.usda.gov/oa/cwd/index.html.
Copyright Environment News Service (ENS) 2002. All Rights Reserved.
© 2001 The Washington Post Company
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