BERLIN (AP) — The World Health Organization says polio is no longer endemic in Nigeria.

Only Afghanistan and Pakistan remain on the list of countries where the disease, which can cause life-long paralysis, is endemic. It can be prevented with a simple vaccination.

The U.N. health agency said in a statement late Friday that no new cases of the disease have been reported in the past twelve months. The last case of wild polio virus was recorded in Nigeria's impoverished north on July 24, 2014.

WHO says the country and Africa as a whole are now closer than ever to being certified polio-free.

The agency said polio remains endemic in Pakistan and Afghanistan and warned that as long as the disease exists anywhere "it's a threat to children everywhere."