British cattle may never be free of BSE despite the introduction of strict animal feed controls, according to a leading expert.
There are calls to relax restrictions on beef
A report in The Sunday Times claims there are still fears the disease could be passed from cows to their calves.
Figures show 54 cases of BSE have been recorded in cattle born after the 1996 ban on meat and bone meal being used in cattle feed.
However, scientists still do not know the cause of the outbreaks, as each occurred on different farms across the country.
Until we have a clear idea the source, it's possible we may see more of these cases and over a longer time scale
According to Professor James Ironside, of the CJD Surveillance Unit in Edinburgh, one possible reason is that calves had been infected by their mothers.
Professor Ironside said he questions whether BSE can ever be totally eradicated.
"Until we have a clear idea what the source of exposure is, it's possible we may see more of these cases and over a longer time scale," he said.
"Cattle might be able to carry the disease for some time."
There is growing pressure on the Food Standards Agency to relax the ban on beef from cattle over 30-months-old.
It is argued that the measure has a lack of scientific justification, with only 16 cases recorded so far this year.
Recommendations on lifting the ban will be delivered to ministers next month.
If accepted, the ban could be replaced by a new testing regime for slaughtered cattle from the start of next year.
Professor Ironside has called for continued surveillance to ensure BSE does not enter the food chain.
BSE has been linked to Creutzfeldt-Jakob Disease (CJD), a disease that causes paralysis and death in humans.