The plant even grows a ring of edible white hairs around the rim of its pitcher to lure its favourite termites into its pit of digestive enzymes. They are then digested.Scientists believe it to be the first confirmed case of a carnivorous plant being selective about its prey, as well as the first example of one offering its own tissue to secure a meal.The researchers often found thousands of termites, all from one sub-group of the insects, inside a single pitcher plant. They noticed that the trichomes, situated around the rim, had disappeared from plants that were full of termites.When pitchers were deliberately placed at the head of foraging columns of termites, the insects quickly started feeding on the white hairs As they did so, they fell into the pitchers. In one case, up to 22 termites per minute were being trapped, but it was thought the capture rate could be even higher. Once the hairs had gone, after about an hour, the pitcher was no longer attractive to the termites.”We don’t know how the trichomes lure termites on to the plant. No long-range olfactory attraction could be detected during our experiments. All contacts seemed to happen by chance, with termites often missing pitchers less than one centimetre away from them,” the scientists said.”Prey specialisation has been proposed for some Nepenthes species, but to our knowledge, N albomarginata is the first example of a carnivorous plant in which this has been confirmed and functionally described, as well as being the only species to offer its tissue as bait.”.

The spectre of smallpox has haunted humanity for more than three millenniums and this year should have marked its final, irrevocable demise. However, a plan to destroy remaining stocks of the virus is about to be abandoned because of fears that one of history’s greatest scourges may now be in the hands of a rogue state. Smallpox: a brief history
* Smallpox, one of the most devastating diseases known to humanity, originated more than 3,000 years ago. It was first described by the ancient Egyptians at the time of the Pharaohs.* Sanskrit medical texts in India describe smallpox epidemics in 1500BC and Thucydides wrote about an outbreak in 430BC that killed one-third of the population of Athens.

* The army of Alexander the Great, above right, was ravaged by smallpox, as were the Abyssinian troops who besieged Mecca on elephants AD570, an incident described in the Koran.* As late as the 18th century, smallpox killed 10 per cent of children in Sweden and France, and every seventh Russian child.* Among the virus’s more famous victims are: Queen Mary II of England, right, Emperor Joseph I of Austria, King Luis I of Spain, Tsar Peter II of Russia, Queen Elenora of Sweden, King Louis XV of France and George Washington, below right.* Edward Jenner invented the first vaccine when he demonstrated that cowpox, a related virus, could be used to inoculate against the human disease.* In the early 1950s, there were still an estimated 50 million cases of smallpox each year. By 1967, these fell to about 15 million cases a year thanks to a global vaccination programme.* Smallpox was finally declared eradicated in the wild in 1979, two years after the last natural outbreak in Somalia and a year after the last accidental infection in a laboratory at Birmingham University. They too were due to be destroyed in the belief that the world would be a better place for eliminating one of man’s most infectious diseases.However, sources close to the WHO committee said the events of 11 September and the subsequent anthrax attacks in America have now made it politically impossible for the committee to recommend destruction of the remaining smallpox stocks.Some scientists on the committee believe further development of vaccines and drugs cannot occur without experiments on the live virus. Destruction, they believe, could ultimately aid terrorists who may have gained illicit access to the virus.The committee reviewed the chilling testimony of Ken Alibek, a former first deputy director of the Soviet biowarfare agency, Biopreparat, who claimed the supposedly secure Russian smallpox stocks might have leaked to agents acting for rogue states. Dr Alibek, who defected to America in 1992, said Russian scientists had “weaponised” smallpox virus and moved samples away from the Novosibirsk facility to other, less secure laboratories in Russia, contravening international agreements.Smallpox is one of the most efficient killers known and if it ever fell into the hands of suicidal terrorists its high infectiousness makes it an ideal candidate for a biological weapon of mass destruction. Anthrax, by contrast, does not spread from person to person.A study by Porton Down scientists published in the journal Nature in December found that there is now so little immunity to smallpox in the general population that a deliberate release could quickly cause a substantial epidemic before public health measures could be mobilised to stop it.

“Although our estimate for smallpox represents a relatively modest transmission rate by comparison with some other infectious diseases, such as measles or chickenpox, significant epidemics could result, particularly if there were delays in detecting the first cases or setting up effective public health interventions,” the report said.American health officials are also keenly aware of the dangers of smallpox if it were to get into the wrong hands. Tommy Thompson, the American Health and Human Services Secretary, recommended in November that the US should not destroy its remaining repositories of smallpox “until adequate medical tools are available to counter any future outbreak of this disease”.Mr Thompson articulated the fears of many experts who are concerned that stocks of the virus may have been illicitly sequestered by potential terrorists. “While known repositories of smallpox exist only in the United States and Russia, it is possible that the virus may also have been acquired by others,” he said. “Until we have developed our defences, we must keep this killer secure but available for needed research. We must be able to counter this virus as well as any altered variant that might be produced.”Some doctors believe there is an urgent need to improve existing smallpox vaccines. Although the vaccines were effective in wiping out the virus from the wild, they cause severe side-effects that limit their use in mass vaccination campaigns against a theoretical threat. As a result, the WHO says that existing smallpox vaccines should be used for only those people exposed to a real threat, such as scientists working in a laboratory where the virus is handled.