vCJD infected 'could be much higher'

The number of people infected with variant Creutzfeldt-Jacob disease - the human form of 'mad cow disease' - could be much higher than previously thought, scientists have warned.

A team from the University College in London said that vCJD could have a longer incubation period, which could be more than 50 years.

Writing in medical journal 'The Lancet', scientists said that exposure to bovine spongiform encephalopathy (BSE) had been widespread, yet only 160 patients had been identified as suffering from vCJD.

The team based their findings on the study of another related condition known as kuru disease, which is a prion disease like vCJD, which is contracted through cannibalism.

The disease reached epidemic proportions in some communities in Papua New Guinea in the early 20th century, due to the practice of eating dead relatives as a mark of respect and mourning.

The practice was eventually banned in the 1950s. However, the study found that 11 patients with kuru were identified between July 1996 and June 2004, with the last one being born in 1959.

Scientists said that this meant that the possible incubation period for the disease could range between 34 and 56 years.

Professor John Collinge, who led the study said that patients with vCJD who had been identified so far could be representative of a "distinct genetic subpopulation" which had unusually short incubation periods for BSE.

The article in 'The Lancet' warned that the eventual size of a vCJD epidemic remained uncertain, while the number of infected individuals remained unknown.

(KMcA/SP)