Marion Merrell Dow Inc. says it has developed a cure for African sleeping sickness, a nervous disorder that afflicts about 25,000 people a year.

The company said Thursday it offered the rights, patent and technology for manufacturing the drug to the World Health Organization royalty-free and would distribute it to African hospitals at cost.The drug, Ornidyl, has been used successfully to treat 600 people without serious side effects, Marion Merrell said.

A spokeswomen for WHO and the federal Centers for Disease Control said Friday their agencies don't know enough to comment on the drug.

One current drug is not effective in the late stages of the disease, African Trypanosomiasis, while another can have serious side effects and can be fatal in 5 percent of the cases.

Marion Merrell began developing Ornidyl as a potential cancer therapy. It was successful in animal tests, but not in humans.

The large pharmecutical company published its research. A Pace University researcher, Dr. Cyrus Bacchi, then discovered it worked against African sleeping sickness.

The disease is caused by parasites transmitted by tsetse flies. Patients experience a variety of symptoms before the parasites invade the central nervous system and eventually cause death.

Ornidyl is administered in large doses over a two-week period at a cost of $140, Marion Merrell said.

An estimated 25,000 people contract the disease each year. The disease occurs in a 10 million square kilometer area of sub-Saharan Africa, where WHO estimates 50 million people are at risk.