It is one of the leading causes of disability in the world and yet it's been neglected for so long

Professor David Molyneux

Elephantiasis is endemic in 80 tropical countries, with at least a billion people at risk from it.

Between 120 and 150m peole are infected with it, and at least 50m have symptoms.

The symptoms are horribly disfiguring - huge enlargement of limbs or genitals.

Women in some countries who get it can find they're virtually unmarriageable. The disease impacts on the sex lives of both women and men. Men with enlarged limbs often can't work.

In some countries, it's still widely believed to be due to witchcraft, or a curse.

However, elephantiasis is wholly treatable and, now, entirely eradicable.

Eradicated from China

In fact, China - where it had been endemic, got rid of it by the 1950s.

The disease is carried by mosquitoes. Once infected, various parasites which otherwise would have no effect, cause the swelling and infections.

Everyone has lots of tiny breaks in their skin - so small you can't see them with the naked eye - and parasitic worms enter through these.

In people with the elephantiasis infection, that's when the disfiguring symptoms emerge.

Eradicating the disease is, from a clinical point of view, easy. You take two drugs once a year for five years.

By that time, not only are you vaccinated for life, but the adult larva which could have re-infected you will have lived out its life cycle and died.

In some communities, as many as 70% of the population is infected: doctors need to treat the entire community to eradicate the disease.

As for those with the symptoms: soap and water is the answer.

Simply washing the infected limb every day - but doing so carefully and ensuring it's properly dried afterwards - ensures small abrasions and lesions don't become reinfected.

That allows the swelling to begin to reduce and may eventually return the limb to normal proportions, or at least a size the sufferer can cope with. The final possibility is surgery - cutting out the infected swollen flesh.

Prohibitive cost

However, in poor countries, the �10 needed for the operation represents a huge obstacle.

Professor David Molyneux has recently stood down from the directorship of the Liverpool School of Tropical Medicine in order to personally take over the elephantiasis programme.

He is motivated by a deep anger that this most treateable of diseases has been so ignored by the Western world.

He says it doesn't kill, it just disables: that, and the ugliness of it has, he believes, led the developed world to grossly under-resource efforts to combat it.

He said: "It's one of the diseases that doesn't kill people - it just disables people, chronic disablement.

"It is one of the leading causes of disability in the world and yet it's been neglected for so long.

"And now we have the drugs which will stop the next generetation ever becoming infected."

With the Gates money, he believes elephantiasis can now be eradicated world-wide within 20 years.

The Liverpool school is not the first to receive a substantial grant from the Gates Foundation to fight tropical disease.

The London School of Hygiene and Tropical Medicine has also benefited to the tune of $40m to fund an anti-malaria drive.