'Mad cow' found in U.K. autopsy; 'Dormant' infection spread via blood transfusion raises questions posted on 8/5/2004 10:31:12 AM
By Anita Manning
USA TODAY
A second case in which the human form of mad cow disease was spread through a blood transfusion has been reported in the United Kingdom. The first such case was reported there in December 2003, and British health officials say they have been expecting more.
The new case is especially significant, scientists say, because the patient shows a genetic variation not seen in previous cases. The finding could change current thinking about who is susceptible to the fatal disease and how long it may lie dormant before causing symptoms.
Few details have been made public about the case. The U.K. Department of Health reported only that a British patient received a blood transfusion in 1999 from a donor who later developed variant Creutzfeldt-Jakob Disease, or vCJD, a brain disease related to mad cow disease. The patient never developed vCJD symptoms and died of unrelated causes, but an autopsy revealed the presence of vCJD infection in the spleen.
Louis Katz, president of America's Blood Centers, says the discovery in a person who showed no symptoms and did not share the same genetic variation as the 150 others worldwide who have died of vCJD raises the question of whether there could be a longer incubation period for the disease, depending on genetic type. That leads to his next question: ''Is the epidemic waning'' as it appears to be, ''or is there going to be a second wave related'' to people with different genetic makeups?
A full report on this case is to be published Friday in the British medical journal The Lancet.
British health authorities responded to the report by tightening blood donor restrictions, but in the USA, Katz says, no changes are expected. Current safeguards that ban donations from people who spent five years in Europe since 1980 or three months in the U.K. from 1980 to 1996 are ''at least adequate and probably more than adequate,'' he says.
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U.S. Will Retest Twice Before Any Mad-Cow Alerts
A WALL STREET JOURNAL NEWS ROUNDUP
August 5, 2004; Page A2
WASHINGTON -- In a bid to avoid alarm and market disruption, the U.S. Department of Agriculture said it will retest any cattle samples that show possible contamination with mad-cow disease before announcing an "inconclusive" result.
This year, there have been two incidents where preliminary results from new rapid tests indicated possible mad-cow disease in animals later deemed clear of the brain-wasting disease. The new rapid tests sometimes produce false positives.
Now, the USDA says, if an initial test shows any sign of possible infection, two secondary rapid screening tests will be performed before any announcements are made. An "inconclusive" result will be announced only if one of those later tests isn't negative, said Ed Curlett, spokesman for the USDA's Animal and Health Inspection Service. Then, the sample would go on for conclusive lab tests.
On June 1, the USDA expanded its mad-cow testing program with the goal of sampling more than 268,000 head of cattle by the end of 2005 to determine the prevalence of the disease, formally known as bovine spongiform encephalopathy, or BSE. As of Monday, 28,812 tests had been conducted, including the two "inconclusives" later ruled as negative.
Cattle ranchers expressed support for the revision. There had been controversy over the USDA's decision to make public the inconclusive results. Some farmers said the announcements depressed prices.
The first U.S. case of mad-cow disease was discovered in December in a Holstein dairy cow in Washington state, prompting dozens of nations to ban imports of American beef. U.S. officials have expressed guarded optimism that negotiations with Japan, the largest foreign market for U.S. beef, will soon result in the resumption of beef exports to Tokyo, which had been halted after the mad-cow finding.
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