Traditional practices at small abattoirs and butchers' shops were probably to blame for a cluster of deaths from vCJD (the human form of BSE) in Leicestershire, an official public health study reported yesterday. Techniques employed to slaughter cows in a number of abattoirs close to the village of Queniborough, coupled with those used by local butchers who were supplied with the carcasses, led to meat becoming contaminated with infected brain material.
The five people who died in what is the first known "cluster" of vCJD in Britain had links with Queniborough and had eaten beef contaminated with BSE-infected brain material between 1980 and 1991. They died between 1998 and last year.
Presenting the findings of a nine-month study into the cluster by the Leicestershire Health Authority, Dr Philip Monk, a public health consultant, said cows were killed using traditional craft techniques for the time.
To ensure cows did not kick during the slaughter process, abattoir officials inserted a rod into the animals' brain. Because it was "plausible" that cows in the area were incubating BSE in the early 1980s, brain material that was infected then leaked into other parts of the animal.
When the meat was supplied to butchers the five people were exposed to BSE's infectious agents - known as prions - because of the way the meat was cut and prepared, probably using the same knives. This led to cross-contamination of infected and non-infected material.
While the study did not provide a full explanation of the reasons for the cluster, or why it occurred in young people, the investigating team said it could point the way forward for further investigation into the 90 confirmed and suspected cases of vCJD in Britain.
The deputy chief medical officer for England, Dr Pat Troop, said the study provided significant evidence of a possible route of transmission, and the data would be analysed by the British government's advisory committee on CJD.