It can cause the limbs and genitals to swell to three times their normal size and affects 120 million people in 73 countries. The plan to eliminate it, launched by the World Health Organisation and the SmithKline Beecham drug company, is one of the most ambitious and will require administration of 4.5 billion doses of medicine over two decades.
One billion people are estimated to be at risk of contracting lymphatic filariasis, the parasitic infestation carried by mosquitoes and which can develop into elephantiasis. The tropical disease is usually contracted in childhood but symptoms usually appear in adults and in men more than women.
In worst-affected communities 10 to 50 per cent of men suffer genital damage, especially hydrocele (fluid-filled enlargement of the sacs around the testes) and elephantiasis of the penis and scrotum. Elephantiasis of the entire leg, arm, vulva or breast can affect one in 10 men and women in these communities. It can have devastating psychological consequences and lead to ostracism for men and women. Young women may never marry or be rejected by their spouses when symptoms appear.
The disease can be cured by a single dose of two anti-parasitic drugs but eradication requires annual dosing of the whole population over four to five years. Parasites in the blood of those affected are spread by mosquitoes.
SmithKline Beecham has agreed to donate one of the drugs required, albendazole, for the duration of the campaign. Jan Leschly, chief executive, said: "We will donate albendazole for use in every country that needs it until this dreadful disease is eliminated as a public-health problem. We expect to see a dramatic decline in five to six years. The entire programme will run for at least 20 years, longer if necessary."