British goat may have harboured BSE

By Debora MacKenzie A British goat which died in 1990 may have had BSE, UK government officials revealed on Tuesday. The discovery means the infection may have circulated in goats in the past, and may even be circulating at low levels today. This follows the recent disclosure of the first natural case of BSE to be found in a goat – a French animal that died in 2002. New Scientist has learned that the British goat was discovered as a result of the French case, as UK government scientists prepared for the increased testing of goats after the discovery. It has long been assumed that sheep and goats may have been exposed to BSE in feed made from infected cattle. But unlike cattle, both creatures can transmit such infections between individuals, which might have kept the disease circulating after infected feed was banned. BSE in sheep and goats would also be hard to spot, as both can naturally develop a similar disease called scrapie which has the same symptoms, although it is not thought to pose a risk to human consumers. And, unlike cattle, sheep experimentally infected with BSE carry the infectious prion in muscle meat, so the infection in sheep and goats could pose more of a risk to consumers. For these reasons European Union countries have been testing sheep and goats for BSE since 2002. These tests discovered the infected French goat. “We were involved in helping evaluate the French data in December,” says Danny Matthews of the UK’s Veterinary Laboratories Agency, the EU reference lab for BSE. It was clear that the EU would probably ask for increased testing in goats as a result, he says. In fact, from February, 80% of healthy slaughtered goats over the age of 18 months, plus “high risk” goats such as those found dead or unable to stand, should be tested, officials have just agreed. Three different test methods – called western blot, ELISA and immunohistochemistry (IHC) – will be used to distinguish scrapie from BSE. “We haven’t had to test many goats in the UK,” says Matthews. “We thought we should test our current IHC on goat brain to make sure it distinguishes BSE.” Besides goats and sheep experimentally infected with scrapie or BSE, they tested two brain samples at random from within a selection of goats thought to have died of scrapie. One of them gave an IHC result that looked like BSE. “We can’t do the other two tests as we processed all the tissue we had from that animal for IHC,” says Matthews. But the team will nevertheless attempt to extract enough tissue from the IHC test material to do the definitive BSE test. This involves injecting tissue into mouse brain to see if BSE develops. But that will not yield results for two years. “What is important now is not what happened back in 1990, but whether the infection is still circulating in goats,” notes Matthews. More on these topics:
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