The families of people infected by the human form of BSE have insisted there must be more research into the disease, after a leading scientist said contaminated beef contained in baby food products or school meals could be the source of infection.
The human form of BSE, which is known as new variant Creutzfeldt-Jackob Disease (vCJD), has killed 67 people among the 75 cases identified in Britain since 1995. An investigation into a "cluster" of five cases among young people is under way in rural Leicestershire.
The director of Britain's CJD Surveillance Unit, Dr Robert Will, said yesterday one explanation of the disease being discovered in high numbers among humans could be the presence of mechanically extracted meat product in baby food and school meals in the 1980s.
The CJD Network, which consists of families of those infected, said Dr Will's theory should be treated seriously. Mr Clive Evers, a spokesman for the network, said: "He is a very eminent researcher and one of the top people in the world on this issue. He has reached the point where they have eliminated many theories. This [theory] seems to be focusing on the potential cause of the infection. It merits further investigation, but how they are going to do that is difficult . . . what remains problematic is the exact source of the infection and the dosage that is needed."
As the investigation into the Leicestershire "cluster" looks back at the childhood eating habits of those infected, Dr Will said one the mysteries of the disease was the large number of young people who had contracted it. A possible link with baby food or school meals could prove to be the key to identifying the source and treating the disease, since the two youngest victims of the disease first showed signs of ill-health at the age of 14. Many vCJD victims were teenagers when they contracted the disease.
Advancing his theory, Dr Will said mechanically extracted beef, which would have been used in cheap meat products such as sausages, pies, beefburgers, pates and some ready-cooked meals, "could have contained remnants of the spinal cord". This is the part of the animal that becomes seriously infected when the cow develops BSE and "foodstuffs which contained that material could be particularly dangerous", Dr Will added. "One possible explanation for the age distribution is that young people tend to eat these products more than the adult population."
Other theories suggested by Dr Will were that young people absorbed the infectious protein particle, prion, which carries the disease, more readily than adults, or that the disease affected the cells of children more than the cells of adults.
The Department of Health said there was "nothing new" in Dr Will's theory. "Everyone knows that the use of mechanically recovered meat in the 1980s was a potential source of tissue for new variant CJD, but nobody should be in any doubt that this is not the case now", a spokesman said.