UCL News


Cannibal study suggests human toll from mad-cow disease could be huge

23 June 2006

The ultimate death toll among humans from mad-cow disease could be massively under-estimated, according to an innovative study conducted among a cannibal tribe in Papua New Guinea.

Variant Creutzfeldt-Jakob disease (vCJD) is linked to eating meat infected with bovine spongiform encephalopathy (BSE), the term for mad-cow disease. Both entail a rogue prion protein that proliferates unchecked in the brain, turning it spongey.

Both diseases have a close relative in kuru, which was spotted in the 20th century among the Fore people of Papua New Guinea who ate the corpses of family members as a sign of respect for the dead. …

British doctors have hit on the idea of seeing whether people there fell sick long after the practice died out, the aim being to determine how long it takes for this BSE-like disease to incubate.

Their suspicions were confirmed, for they identified 11 people who were diagnosed with kuru between July 1996 to June 2004. …

The paper, which appears in Saturday's issue of 'The Lancet', has important implications.

At present, there are 161 known cases of vCJD in Britain, where the BSE epidemic erupted, along with 17 in France and a handful of other cases in Canada, Ireland, Italy, Japan, the Netherlands and the United States.

As vCJD only surfaced as a disease little more than a decade ago, this relatively tiny toll has eased initial worries that tens of thousands of people could die, given that millions of people ate BSE-infected beef. …

But the big unknown about vCJD is how long it takes to incubate and whether, as genetic analysis is tentatively starting to suggest, some people are more vulnerable or more resistant than others.

The authors of the new study, led by Professor John Collinge [UCL Institute of Neurology], say they fear that vCJD patients identified so far may be a "distinct genetic sub-population" which made them easy targets for the rogue protein.

In other words, people who are otherwise healthy today may fall sick with the lethal disease a few years or more than half a century down the road.

"A human BSE epidemic may be multiphasic," says Collinge. "Recent estimates of the size of the vCJD based on uniform genetic susceptibility could be substantial under-estimations."

Agence France Presse