The number of deaths due to vCJD, the human form of mad cow disease, has now exceeded 100, according to government figures revealed yesterday.

In the first five months of this year, 16 confirmed or suspected new cases of vCJD have come to light, raising fears amongst scientist that the death toll is set to continue rising. If new cases emerge at the same rate, another 28 cases can be expected by the end of the year.

Government advisors are also warning that the epidemic could actually be far worse than thought because of the number of elderly patients who die undiagnosed. They are suggesting that post mortems should be carried out on elderly patients who die with suspected dementia, a symptom of the brain wasting vCJD. Generally, the deaths have occurred in people aged in their 20s and 30s.

Prof Roy Anderson, an epidemiologist at Imperial College, London, and a member of the government advisory body the Spongiform Encephalopathy Advisory Committee (SEAC), had predicted that the number of vCJD deaths would be between 100 and 10,000.

Others modelled more conservative patterns for the disease however, and there is some shock amongst professional bodies that the death toll has reached 100. Prof Peter Smith, SEAC chairman, commented: "It is an arbitrary landmark, but obviously every additional case is of great concern. But it has reached 100 and some of the earlier predictions were that it would not reach 100. We don't know how it's going to evolve."

SEAC called for more post mortem examinations to be conducted on elderly people who die with suspected dementia, in case vCJD is being misdiagnosed as Alzheimer's or senility.