NR ASNH
AU Walker,M.
TI A lesser evil - Human BSE may kill thousands, but it could have been worse
QU New Scientist, 22 Jan 2000
IA http://www.newscientist.co.uk/news/news.jsp?id=ns222247
PT News
VT
THE horrific possibility that millions of people in Britain will fall victim to the human form of BSE is looking increasingly remote. The latest figures suggest that the final death toll is likely to be on the scale of thousands rather than millions.
Researchers at the Wellcome Trust Centre for the Epidemiology of Infectious Disease in Oxford have worked with statistics on how many infected cows were slaughtered, how much infected material entered the food chain and the course of the cattle epidemic. From this, they have produced a model describing the likely course of Britain's epidemic of new variant Creutzfeldt-Jakob disease (vCJD), the disease linked to the consumption of BSE-infected meat.
With this model, they can use figures on the number of cases in 1999 and 2000 to predict the maximum size of the epidemic. "1999 may be a bit of a turning point," says Christl Donnelly, a statistician on the team.
If 15 people or fewer died from vCJD in 1999, the model predicts that any epidemic will reach a maximum of half a million cases in total. If there is no increase and a similar number die in 2000, then it predicts that any epidemic will peak at a total of 14 000 cases or fewer. So far, nine deaths from vCJD have been confirmed for 1999, according to the national CJD Surveillance Unit in Edinburgh. It is still too early to put a final figure on the year's toll, but the current figure is less than that reported for 1998 at this stage last year. In January 1999, 12 deaths had been confirmed for 1998, a figure that eventually rose to 17. "It's good news that we haven't seen so many cases so far," says Donnelly.
The model assumes that only a certain proportion of the population is susceptible to vCJD. All the known vCJD victims had two copies of a particular variant of the gene for a protein called PrP. This trait is shared by about 40 per cent of the British population. However, it could be that other people are also susceptible, but will take longer to display symptoms.
Source: Proceedings of the Royal Society B (vol 267, p 23)
Matt Walker
ZR 1 Zitat
SP englisch