A drive to eliminate one of the world's most disfiguring and disabling tropical diseases has seen 80m people treated in just four years.
Elephantiasis is caused by a microscopic, parasitic worm
The elephantiasis programme, led by the World Health Organization, is being hailed as the speediest ever global public health campaign.
A simple two-drug cocktail once a year is enough to give protection.
Elephantiasis can lead to huge enlargement of the arms, legs and genital organs.
The leaders of the initiative estimate that it has significantly reduced the threat of the disease in at least 37 countries where it has been a major problem.
It is estimated that 30 million of those who have received the drugs since the elimination drive was launched are children.
In total, it is estimated that one billion people in 80 tropical countries are at risk from the disease, also known as lymphatic filariasis (LF), and 120 million people actually carry the infection.
In many endemic regions, the infection is found in as much as 25% of children aged four to six-years-old, but early damage is hidden and no immediate signs of LF are visible.
A parasitic worm causes the disease
The disease is caused by a microscopic, parasitic worm that invades the body's lymphatic system. It is spread by mosquitoes, who pass it on when they take blood from humans.
Once in the blood stream, the worms live for four to six years, producing millions of immature microfilariae, minute larvae that circulate in the blood.
Transmission of LF can be prevented by administering the drug albendazole plus either of two other drugs, ivermectin or DEC.
Research has shown that the two-drug combination is up to 99% effective in removing microfilariae from the blood for a full year after treatment.
Supplies of albendazole have been donated by manufacturer GlaxoSmithKline.
JP Garnier, the company's chief executive, said: "We estimate that it will take approximately 20 years to break the cycle of the disease globally.
"But we have the proof now that it is practical to eliminate this ghastly disease completely, within our life times."
Dr David Molyneux, a tropical disease expert at Liverpool School of Tropical Medicine, said LF was almost unheard of in the West as symptoms only usually become apparent following multiple mosquito bites over a long period of time.
As a result, he said, the disease had been largely ignored by policymakers in many developed countries.
He said: "This is a disease that affects the poorest of the poor.
"In diseases like tuberculosis, HIV and malaria where parasites, bacteria and viruses develop resistance, part of the medical challenge is to stay ahead of the mutations.
"The LF worms, on the other hand, are slow growing and for a number of reasons are less likely to develop drug resistance. It makes the goal of ending the disease realistic."