Eliminating an infectious disease by deliberately eradicating the causative agent has happened only twice: smallpox fell in 1977 and rinderpest – cattle plague – in 2011. Polio should be next, but the murders in the last week of vaccinators in Pakistan – one in Charsadda, two in Peshawar, five in Karachi – have stopped the eradication programme. Nothing new for the Taliban, who blocked polio immunisation in Waziristan earlier this year. Things haven’t been helped by the disclosure that Dr Shakil Afridi, whose activities helped to locate Osama bin Laden in Abottabad, operated under the cover of a bogus immunisation programme run by the CIA.
The polio eradication campaign has always faced more political and religious opposition than the smallpox campaign did. In the early stages, meaningful polio incidence figures were hard to come by. Some countries’ official statistics showed very few cases, but they were contradicted by the number of children in the streets with withered legs.
The most recent polio data were published by the WHO on 12 December. The disease is endemic in only three countries: so far this year, Pakistan has reported 56 cases, Afghanistan 34 and Nigeria 118. Even if the eradication programme is quickly resumed in Pakistan, the next nasty to become extinct will not be polio. It will be the Guinea worm, the cause of dracunculiasis. The female worm is nearly a metre long. It burrows through the body to surface at the ankle. The intense pain causes the sufferer to plunge the foot into water. This causes the worm to lay and eject its eggs. They are eaten by water fleas. Drinking a flea infects. Transmission is prevented by filtering water through a cloth or treating it to kill the fleas. When the Carter Foundation started its programme to eliminate the worm in 1986 there were 3.5 million cases. In 2012 there were 521.