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Canada nears end of mad cow probe

Twenty-day search turns up no new cases

Twenty-day search turns up no new cases

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  • Mad cow disease was first reported in the United Kingdom in 1986, peaking in 1993 with almost 1,000 new cases per week. 
  • In 1996, variant Creutzfeldt-Jakob Disease (vCJD) was detected in humans and linked to the mad cow epidemic. Eating contaminated meat and cattle products is presumed to be the cause.
  • Both are fatal brain diseases with unusually long incubation periods, often lasting years.
  • To date, no case of mad cow disease has been identified in the United States.
  • As of April 2, 2002, a total of 125 cases of vCJD had been reported in the world: 117 from the United Kingdom, six from France, and one each from Ireland and Italy.
    Source: CDC
  • (CNN) -- A Canadian health official Monday said tests of more than 1,500 cattle in the 20 days since a single case of mad cow disease was identified in Alberta have found no more cases, and the active investigation is drawing to a close.

    "So far, other than the original cow, all test results have come back negative for [bovine spongiform encephalopathy]," said Dr. Brian Evans, chief veterinary officer with the Canadian Food Inspection Agency, using the scientific name for mad cow disease. "We can remain confident that the systems in place in this country have worked to detect the presence of BSE and to prevent its spread."

    A four-person international review team has "validated our findings and concurred that the active, investigative stage has achieved its maximum potential," Evans said.

    The head of that review team, Dr. Ulrich Kihm, director of Safe Food Solutions, lauded the Canadians' efforts but predicted that other cases will be found.

    The infectious agent takes at least six to eight years to cause symptoms in cows, meaning that the infected cow was likely spreading the disease during that time. "There are very few countries in the world where there is only one case. Normally there are more. One has to look properly," Kihm said.

    But, even if no other sick cows are identified, it could take years before Canada would be in a position to declare its cattle free of the disease, Kihm said.

    The fatal brain-wasting disease is believed to be spread through contaminated cattle feed and cannot be passed from cow to cow. A human disease -- variant Creutzfeldt-Jakob Disease (vCJD) -- was first identified in 1996 and linked to eating mad cow-contaminated meat and cattle products.

    U.S. officials have not said when they will re-open the border to Canadian cattle. A temporary ban on importing Canadian beef was put in place in May.

    One U.S. official said he was encouraged by the absence of new reported cases but said he would await the formal report before considering lifting the restrictions.

    "I would hesitate to speculate on how long that would take, because I just don't know how much follow-up and additional information might be generated when we take a look at it," said Dr. Ron DeHaven, deputy administrator of animal, plant and health inspection services for the U.S. Department of Agriculture.

    Since the discovery of the case, U.S. representatives have been in Canada overseeing and reviewing the Canadians' efforts, Evans said. Nine of 18 farms remain under quarantine.

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