ACCRA, Ghana - Jimmy Carter watched in horror as the centimetres-long worm emerged from the breast of a woman in remote northern Ghana. That was in the 1980s. The former U.S. president dedicated himself to eradicating the sickness and estimated it would take 10 years.

On Thursday, after 23 years of hard work and a major setback, Ghana finally declared victory.

"Ghana's triumph over Guinea worm disease serves as a reminder to the world and the remaining endemic countries that the greatest challenges can be overcome with hard work, political commitment, and the support of the international community," Carter said in a statement from the Atlanta-based Carter Center.

At a celebration in Ghana's northern Tamale city, Vice-President John Mahama announced that the West African nation has completed 14 consecutive months reporting no indigenous cases, indicating that the cycle of Guinea worm disease, or dracunculiasis, has been broken.

Ghana had 180,000 cases in 1989. By 2005, it had only a few hundred. Then, in January 2007, more than 1,000 new cases were reported in northern Ghana, in what Carter called "our worst disappointment" of the international campaign.

Guinea worm eggs lodge in a microscopic water flea, which people swallow with untreated water, usually at sources that they share with animals and where they bathe, wash clothes and collect drinking water. So the disease attacks the poorest of the poor. The eggs live in abdominal tissue where they hatch and mate. A year later, the worm starts emerging, most often through legs and feet and measuring a yard (meter) and more, in a process so painful it can stop people from working for three months.

To relieve the fiery pain, victims put a foot in water, and the worm emerges and breeds. Just one worm can discharge a million eggs. So hundreds of people can use a dam safely and one child can ruin the communal effort.

Guinea worm does not kill and there is no treatment or vaccine. Instead, water filters are distributed, a mild pesticide kills the flea carrier in water holes, and villagers are counselled to drink only safe water and stay out of infected water.

Carter said Ghana's setback was caused by putting too little emphasis on these simple steps, and instead focusing on providing expensive water systems.

Aid workers had built dams in low-lying flat areas to catch rainwater, dams that in the dry season became breeding reservoirs for Guinea worm.

Carter came to Ghana in early 2007 to help redouble efforts in the country, declaring he was determined "to outlive the last Guinea worm." He is now 86.

Guinea worm disease remains endemic in newly independent South Sudan and in pockets of Mali and Ethiopia. Chad also recently experienced an isolated outbreak.

Some 804 cases have been reported in those countries this year. When Carter began his campaign, there were more than 3.5 million cases in 23 countries in Africa and Asia.

"The last cases of any disease are the most challenging to wipe out," said Dr. Donald Hopkins, vice-president of health at the Carter Center, who attended Ghana's celebration.

Guinea worm could be the first parasitic disease eradicated, and only the second disease to be eradicated in the world, since smallpox in 1979.