Red-hot news on the science wires from Peru today, as it emerges that US federal boffins have identified six people who have apparently suffered no ill effects from being bitten by infected, blood-drinking VAMPIRE BATS: such attacks are typically fatal.

"Our results open the door to the idea that there may be some type of natural resistance or enhanced immune response in certain communities regularly exposed to the disease," says Amy Gilbert of the US government Centers for Disease Control, leader of a team which identified the mystery six individuals.

The apparently unharmed bat-bitten half dozen live in the remote villages of Truenococha and Santa Marta, far from civilisation on the Peruvian Amazon. The locals there are much plagued by vampire attacks, which are typically deadly.

The fatal nature of the bat attacks is not, however, due to them actually draining their victims of blood to the point where they die. The bats do drink the villagers' blood, but naturally being small they can't take enough of it to kill a human being. They generally attack sleeping people, making use of an agent in their saliva known as "draculin" to prevent their victims awakening and/or the bite scabbing over.

The deadliness of the bites arises due to the fact that many of the bats are infected with rabies, a disease which typically kills unprotected humans. Gilbert and her colleagues from the CDC and the Peruvian Health Ministry, in common with the world medical profession in general, had thought that a rabies infection in a human - unless treated almost at once, or prevented in advance by means of vaccination - would be invariably fatal.

That turns out not to be the case, however, with a half-dozen of the hardy Amazonians in Gilbert's study having been bitten without any previous vaccination, duly suffered from rabies (and developed the antibodies in their blood samples to prove it) and yet recovered unassisted.

"We all still agree that nearly everyone who is found to be experiencing clinical symptoms of rabies dies," Gilbert said. "But we may be missing cases from isolated high-risk areas where people are exposed to rabies virus and, for whatever reason, they don't develop disease."

The fact that some people can apparently beat rabies without vaccination or immediate treatment on infection offers hope that medical science can one day find a proper cure for the disease, which is normally incurable once it has developed and kills its victims in a particularly traumatic way. Britain, in common with other nations free from the disease, has stringent border quarantine controls on animal movement to prevent its spread, an indication of how seriously rabies is viewed.

The benefits of the new discovery could be much greater in the vampire-haunted villages of the Amazon.

"These are very small villages and, when they witness ten people dying from what is a horrible disease, it is incredibly traumatic," Gilbert said. "We want to help raise awareness of the problem and try to develop a more proactive response."

Gilbert and her colleagues' paper reporting their discovery can be read here by subscribers to the American Journal of Tropical Medicine and Hygiene. ®