By Matthew Bigg

ATLANTA, Dec 5 (Reuters) - Health workers are on the verge of eradicating Guinea worm disease in what would be just the second time in history a disease has been wiped from the planet, the Carter Center said on Friday.

Cheap interventions such as hygiene education, using larvicides to kill the worm and distributing inexpensive cloths to help filter parasites from drinking water have cut the infection rate by 99 percent, reported the center founded by former U.S. President Jimmy Carter.

Fewer than 5,000 cases of Guinea worm disease, also known as dracunculiasis, remain in Mali, Niger, Ghana, Nigeria, Sudan and Ethiopia, the center said.

There were around 3.5 million cases in 1986 when the global effort to get rid of the disease, led by the Carter Center, began. Last year the number had dropped to 9,600.

The center announced a new commitment of $55 million from the Bill and Melinda Gates Foundation and Britain's Department for International Development to push towards an end to the disease.

By 2009 the Center and U.N. World Health Organization say they hope there will be no cases and the following year the disease could be declared dead. A global vaccination effort eradicated the smallpox virus in 1979.

"The reduction of Guinea worm cases by more than 99 percent proves that when people work together, great positive change is possible," Carter said in a statement.

The parasitic worm affects people who live in extreme poverty and drink stagnant water containing the larvae without boiling it. It is mainly found in parts of rural Africa.

Few people die from Guinea worm, but it is very debilitating with fevers, blisters and extreme pain.

The female worm resides inside its host's intestine for a year and can grow to three feet (one meter) before piercing the skin and emerging inch by inch (centimeter by centimeter) over a period of weeks in the lower limbs, the roof of a victim's mouth or genitals.

The disease can be eradicated without vaccines or drugs because of the manner in which guinea worms reproduce, said Craig Withers of the Atlanta-based Carter Center.

A worm must lay its eggs in stagnant water before it dies and is thus dependent on human contact with water for transmission. Once the eggs are in water, an animal called a water flea ingests them and the eggs become larvae and mature.

"When a person drinks water that contains the water flea and its larvae they become infected," Withers said.

But that transmission process can be blocked through education of villagers and the vigilance of public health officials working in rural areas.

If the 5,000 known cases are cared for and kept away from stagnant water the guinea worms within them will die without laying their eggs and the disease's cycle will be broken.

"We think that it (eradication) is doable in every country but southern Sudan is the greatest challenge because of the number of cases, the size of the area and the lack of infrastructure," said Withers.

Since 1987, around $225 million has been spent on eradication -- a relatively small sum in public health terms.

Fighting guinea worm has been central to the post-presidential work of Carter, who left office in 1981. The Center focuses on conflict resolution, promoting democracy and human rights and health and agricultural programs.

(Editing by Maggie Fox and Jackie Frank)

AlertNet news is provided by