More than 120 million people worldwide are infected with elephantiasis, and one billion more are at risk of contracting the debilitating and disfiguring ailment. Infection is rampant in parts of Africa and Asia, but stepped-up efforts to combat the parasitic disease are under way.
Lymphatic filariasis, more commonly known as elephantiasis, afflicts many of the world's most vulnerable communities. A parasite that infects the human lymphatic system is responsible for elephantiasis, which causes swelling and deformity of the limbs and other body parts.
Mosquitoes spread the tiny parasitic worm that causes elephantiasis from person to person.
The disease is endemic in 83 tropical countries, and Professor David Molyneux of Britain's Liverpool School of Tropical Medicine says anyone living in those places is at risk. "The total numbers of people which have been estimated by the World Health Organization to be at risk in these 83 countries is about 1.3 billion people, so let's say a fifth of the planet is at risk," he says.
There are few conditions in the world more socially alienating. The Global Alliance to Eliminate Lymphatic Filariasis has been at the forefront of those fighting the disease. As the group's video shows, elephantiasis mainly affects the rural poor, forcing infected people - like this man from Uganda - further into poverty. "I am a carpenter. It's quite a problem for me when I have to stand at my work for long periods," he says.
Washing infected limbs can help ease the suffering, but it does not cure or stop the spread of the condition.
This man comes from a village in Tanzania where elephantiasis is endemic. "I do not mind being seen in public because many other people have this disease, too," he says.
Set up nine years ago, the Global Alliance aims to eradicate elephantiasis as a public health threat by 2020.
The group has teamed up with the U.N. World Health Organization and major drug companies such as GlaxoSmithKline and Merck.
Andy Wright heads up GlaxoSmithKline's elephantiasis program. "When the program started, there was a global plan produced by the WHO for how you could achieve this goal within 20 years, and progress against that plan is very much on target. So there is a lot of very strong evidence that the program is succeeding, and a lot of confidence that in the vast majority of countries, it will be successful before 2020," he says.
The eradication program consists of two drugs - albendazole, donated by GlaxoSmithKline, and Mectizan, donated by Merck. Those living in endemic areas take two pills a year for five years. The drugs significantly reduce the number of worm larvae in the blood, which means far fewer mosquitoes carry the infection to those they bite. "We made an agreement with the World Health Organization to donate one of our anti-parasitic drugs, albendazole, to every country that needs it, until the disease is eliminated. And that's an enormous commitment that will take 20 years or more, and will involve billions [of doses] of ... albendazole," says Wright.
Despite these efforts, there is much more to do in the fight to eradicate lymphatic filariasis. Populous countries, such as Nigeria and Indonesia, and others face logistical problems in delivering and implementing the program nationwide.
Professor Molyneux says it should be viewed as the most important public health program of our generation. "If we can't afford to implement this intervention within existing health financing environments, I don't believe we could afford to do anything in public health," he says.
Elephantiasis was once considered one of the world's most neglected afflictions, but those fighting it hope that by 2020 the disease will be gone.