Epidemic unlikely from n.variant CJD
AN EPIDEMIC of new variant Creutzfeldt-Jakob Disease is looking increasingly unlikely, according to John Pattison, chairman of the governments BSE advisory committee, SEAC.
"The rate of appearance of new cases (of nvCJD) has not increased at all since the first case appeared in May 1995," he told last weeks Agra Europe Meat 97 conference in London.
So far this year there had been seven new deaths, on top of the 13 already recorded since 1995. And while there was now proof of a link between BSE in cattle and nvCJD in humans, there were still doubts about the average incubation period.
Analysis showed that if it was about 10 years, then 12 deaths would be expected in 1997, and there could be between 100 and 200 cases before the disease died out.
But the worst case scenario, with an average incubation of 25 years, could mean an eventual death toll of up to 80,000 people.
"It encourages me to think that our worst fears will not be realised," said Prof Pattison. With only seven cases so far this year, the chances were that the average incubation would be between 10 and 15 years. As with AIDS, as time passed, those predictions would become more and more accurate, he added.
But, the bad news for the industry was that there was likely to be a huge variation in the incubation period between individuals, which would keep BSE and nvCJD in the public eye for perhaps another 12 years.
Prof Pattison dismissed any worries that farmers were at greater risk of nvCJD. Experiments with mice had shown that those treated with infected material from farmers who had died of the brain disease displayed all the symptoms of classical CJD rather than nvCJD or BSE.
As for the recent case of a girl who has the disease and has been a vegetarian for 11 years, Prof Pattison said: "We still believe the most likely explanation was exposure to beef offal in beef products before she became a vegetarian in 1985."n