February 01, 2012

 

 BSE in goats can be mistaken for scrapie

Posted on January 15, 2012
 

Bovine spongiform encephalopathy in goats could be misdiagnosed as scrapie in the absence of appropriate discriminatory tests, and such misidentification occurred at least once before such tests were developed, according to a report released in December.

The article, "Isolation of prion with BSE properties from farmed goat" (Emerging Infectious Diseases 2011;17:2253-2261), indicates BSE can affect small ruminants under natural conditions and that the condition can be misdiagnosed. The agent that causes scrapie is not known to infect humans, but consumption of beef contaminated with the prions that cause BSE is connected with variant Creutzfeldt-Jakob disease, a neurodegenerative disorder in humans.

The report calls for continued extensive surveillance and breeding plans to prevent BSE outbreaks among small ruminants. Such outbreaks could harm public health.

The authors stated in the text that the misdiagnosis occurred in 1990 in the United Kingdom. The case had been identified as suspected BSE in 2006 because differential immunohistochemical analysis of fixed brain tissue produced a signature indistinguishable from BSE. The authors of the recent report used a bioassay to confirm the BSE diagnosis.

The sample collected in 1990 was among 26 historic samples collected from 1984-2002, the report states.

The report indicates the U.K. goat and a goat in France found to have BSE in 2005 both likely became infected through contaminated food supplements.

While BSE lesions are contained mainly within nervous tissue in cattle, the report states "in small ruminants the BSE agent is widely distributed in peripheral tissues and can be transmitted horizontally." Feed ban measures alone would be insufficient for controlling a BSE outbreak in small ruminants, according to the report.

"Also, it would be impossible to prevent BSE from entering the human food chain through consumption of food products derived from small ruminants," the report states.