Report of the first oral inoculation of BSE prion into cattle in Japan
Ryoko Irie, Hiroyuki Okada, Hiroko Hayashi, Yoshifumi Iwamaru, Taka- shi Yokoyama and Morikazu Shinagawa
Prion Disease Research Center, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba 305-0856 Japan <e-mail> [email protected]
Abstract
A Prion Disease Research Center at the National Institute of Animal Health (NIAH) was established to conduct comprehensive research on BSE in response to the discovery of bovine spongiform encephalopathy (BSE) in Japan. A nevs^ research facility for the center has been con- structed. It was designed as a biosafety level (BSL) 3 facility with the capacity to inoculate and hold experimental animals. Experiments have begun to infect cattle with BSE orally. This route of inoculation simu- lates the feeding of contaminated meat and bone meal that caused pan- demic occurrence of BSE in the UK. An abnormal isoform of the prion protein (PrP^^) accumulates in BSE affected cattle. The purpose of this study is to examine the spread of the abnormal prion from digestive tract to the central nervous system and to describe the pathological changes in cat- tle during the course of infection. Atypical BSE and young BSE cases have been found in the abattoir surveillance program. As a result the cat- tle used in this experiment were imported from Australia, a country free of BSE, to exclude the possibility of prior BSE infection before inoculation.
Each calf (Holstein heifer, 10-months old) was inoculated orally with 5g of brain stem from BSE infected cattle (courtesy provided by Veterinary Laboratory Agency, Weybridge, UK) into the rumen with a catheter. The cattle will be euthanized at intervals during the clinical stages of disease.
Infectivity from different tissues at different stages of clinical disease as well as the deposition of PrP^^ will be analyzed. Other factors that may be related to the pathogenesis of the BSE prion will be investigated.
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