Geneva ? Africa is on the brink of the biggest polio epidemic in years, with the crippling disease hitting Nigeria hard and re-emerging in Sudan’s war-ravaged Darfur region, the World Health Organization said Tuesday.

The number of polio cases globally is 333 so far this year, almost double the number for the same period last year. Total cases last year reached 783.

In Nigeria, where Muslim leaders have refused to participate in an immunization program, 257 cases have been reported this year.

“There is no question that the virus is spreading at an alarming pace,” said Dr. David Heymann, who is overseeing the U.N. health agency’s effort to eradicate the disease.

Polio is a water-borne disease that usually infects young children, attacking the nervous system and causing paralysis, muscular atrophy, deformation and sometimes death.

Nearly 1,000 children in 125 countries were being infected daily by polio in 1988 when WHO and other health organizations launched the Global Polio Eradication Initiative.

That number dropped to 483 for the whole of 2001, and health officials declared the disease was eradicated in Europe, the Americas, much of Asia and Australia.

Epidemiologists now fear a major epidemic this fall — the start of the polio “high season.” The disease has appeared already in nine sub-Saharan African countries, compared with two at the beginning of last year.