Polio has been stamped out in Egypt and Niger, leaving just four nations in the world where the deadly disease is endemic, the U.N. health agency said Wednesday.

The polio virus has not infected anyone in the two African countries during the last 12 months, leaving only Afghanistan, India, Nigeria and Pakistan as countries where the disease is still classified as endemic — meaning it has always been present there, the World Health Organization said.

Polio is still present in eight further countries, including Indonesia and Yemen, where it had previous been eradicated before being imported again from one of the endemic countries, WHO said.

"Polio has been endemic in our country for all of recorded history," Egypt's Health Minister Dr. Hatem Mostafa El-Gabaly said. "The best tools of our age finally defeated this enemy, who has been with us from pharaonic times."

Geneva-based WHO failed to meet its long-standing target of eradicating polio globally by the end of last year after hard-line Islamic clerics in northern Nigeria led an immunization boycott in 2003. They claimed the polio vaccine was part of a U.S.-led plot to render Nigeria's Muslims infertile or infect them with AIDS.

The Nigerian vaccine boycott was blamed for causing an outbreak that spread the disease across Africa, into the Middle East and as far as Indonesia. But WHO said the disease could be eradicated almost everywhere in the first six months of this year and in other countries — notably Nigeria — in 2007.

"The finish line is in sight," said Dr. David Heymann, the WHO official responsible for global polio eradication. "We're optimistic that great progress will continue to be made in 2006."

WHO said the success in Egypt and Niger was the result of intense efforts to halt Africa's epidemic by speeding up the introduction of new vaccines into affected areas. In the last three months of 2005, the number of cases in India and Pakistan also fell by more than half compared to the previous year.

"To fully exploit these new tools, government commitment in Nigeria must remain high at all levels to ensure that all children are vaccinated," said Jonathan Majiyagbe, a former president of Rotary International, which has contributed more than $600 million for eradicating polio.

Vaccination programs began again in Nigeria in July 2004 after local officials ended the 11-month boycott. But the delay effectively set global eradication efforts back at least a year.

Last year, some 1,880 people were infected with polio around the world, 727 of them in Nigeria.

When WHO launched the $4 billion anti-polio campaign in 1988, the worldwide case count was more than 350,000 annually.

Polio is spread when people — mostly children under 5 — who are not vaccinated come into contact with the feces of those with the virus, often through water. The virus attacks the central nervous system, causing paralysis, muscular atrophy and deformation and, in some cases, death.