COMMENTARY

Infectious Diseases: February 15, 2004

John Bartlett, MD

Disclosures

February 17, 2004

In This Article

Prion Diseases

CJD (New Variant) – UK: Update 2004 [UK Department of Health Monthly CJD Statistics 1/5/04 ProMED 1/6/2004. The total number of definite or probable cases of new variant Creutzfeldt-Jakob disease (vCJD) is 145, including 6 patients who are still alive and 139 who have died. Of the 139 who died, 103 were confirmed vCJD and 34 did not have neuropathologic confirmation. The initial report of deaths was 3 in 1995; this subsequently increased to a peak of 28 in 2000 and decreased to 18 in 2003. The report notes that there is experimental evidence of transmission in mice, suggesting that "some patients with a phenotype consistent with sporadic CJD may have disease from BSE exposure."[27] For this reason, figures for sporadic CJD may have significance with respect to the vCJD outbreak. During the period 1990 to 2003, there were 692 deaths attributed to sporadic CJD in the United Kingdom. The number of cases by year since 1995 is summarized in Table 12 .

CDC. Bovine spongiform encephalopathy in a dairy cow—Washington State, 2003. MMWR. 2004;52:1280. This is the report of the case of bovine spongiform encephalopathy (BSE) that was diagnosed on December 23, 2003 in the United States. The following summarizes the observations to date:

The cow: The 6.5-year-old, BSE-positive cow was a "downer" (meaning nonambulatory), and was disabled, presumably due to complications from calving. It was slaughtered on December 9th. Brain tissue was tested by the USDA's Animal and Plant Health Inspection Service, since this is routine with downer cows. The test was positive on December 23, 2003 and was the first positive test ever recorded in the United States out of a total of approximately 57,000 tested cows since 1990. This result was confirmed in the BSE international reference laboratory in Weybridge, England, on December 25, 2003.

Recall: The carcass was released for food. Tissues that are considered potential risks for transmission of BSE include brain, spinal cord, and small intestines; these tissues are routinely removed from the cow during slaughter and sent for inedible rendering. On December 24, Food Safety and Inspection Service (FSIS) recalled the beef from cattle slaughtered in this same plant and recalled the products from the rendering plants.

Trace-back: The BSE-positive cow has been traced to a farm in Alberta, Canada, and DNA evidence links this cow to 1 of 82 in a Canadian herd that was shipped to the United States on September 4, 2001. The rest of this herd is now being pursued. The BSE-positive cow gave birth to 2 calves in the United States, including 1 that was on the same US farm and the second at another location; the second calf could not be definitively identified, so all calves at this site have been sacrificed.

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