The World Health Organization, WHO, says the world could eradicate the parasitic disease of guinea worm within two years.

The U.N. health agency has certified another 12 countries as free of guinea worm, a crippling affliction that sickened three million people in the early 1980s, but now affects only about 25,000 people in nine African countries.

Guinea worm disease is spread by contaminated water. Victims develop large ulcers that swell, burst, and release a spaghetti-like parasitic worm that can reach almost a meter in length.

The WHO says nearly all remaining cases are in Sudan, which has about 20,000 sufferers. Ghana has 4,000.

The disease is also still found in Burkina Faso, Nigeria, Ivory Coast, Ethiopia, Mali, Niger, and Togo.

So far, health workers have managed to completely eliminate only one other disease - smallpox.

Some information for this report was provided by Reuters.