Wednesday, May 19, 1999 Published at 06:45 GMT 07:45 UK
BSE fears over US blood imports
No sign of mad cows in the USA - but some scientists say the signs are there
By Environment Correspondent Alex Kirby
There have been no cases of BSE - bovine spongiform encephalopathy, or "mad cow disease" - in North America.
But a BBC programme says some experts fear a new kind of Creutzfeld-Jakob Disease (CJD), the human equivalent of BSE, is killing young Americans.
The programme, "BSE - The Untold Story", was broadcast on Radio 4.
CJD is normally a disease of elderly people, but the type linked to eating the meat of BSE cattle - new variant CJD - attacks young patients.
CJD is not a notifiable disease in the USA, so there are no accurate figures on the number of cases or the ages of patients.
A Washington lawyer, Andrew Kimbrell, told the programme: " We've seen explosions of cases.We're facing what the UK faced a few years ago".
"Is it a time bomb? Is it just something that a few people seem susceptible to?"
US supplies thought safe
Mr Kimbrell wants an investigation into the possibility that the country's blood supply may be infected with CJD.
Britain started importing blood plasma from the US last week, because of "the theoretical risk" that CJD could be spread by infected British blood supplies.
A zoologist, June Goodfield, says that if eating meat caused infection by CJD, there would have been many more cases by now.
The programme cites earlier studies of the Fore tribe in Papua New Guinea, who suffered from a similar brain disease called kuru.
These studies suggested the disease was spread when people handled the flesh of kuru victims, rather than when they ate it.
They suggested the infectious agent could enter the bloodstream through cuts and bites, or through mucous membranes.
Professor Sir John Pattison, who chairs the Spongiform Encephalopathy Advisory Committee, told the programme he had no evidence of a new CJD strain in the USA.
The programme also says it has seen estimates of the likely number of British CJD victims, which were prepared for the Royal Society.
These say there could be as few as a dozen more deaths, or as many as thirteen million.