SYDNEY Commonwealth leaders on Saturday vowed to step up the fight against polio, but said the Afghanistan war was hindering the fight and warned that without total eradication there could be a resurgence of the crippling disease.
Polio remains in just four countries, India, Pakistan, Nigeria and Afghanistan -- the first three members of the Commonwealth.
Leaders from Britain, Canada, Australia and Nigeria, and U.S. billionaire Bill Gates, on Saturday pledged tens of millions of dollars in extra funding to wipe out the disease.
"It will be an investment in saving lives," Australian Prime Minister Julia Gillard said at a joint news conference with the other leaders on the sidelines of a Commonwealth summit.
Global polio infection rates had fallen from a high of 350,000 a year to a current low of 1,000 a year, said Britain's Prime Minister David Cameron.
"We are now within sight of the great goal of eradicating polio. But nearly eradicating is just not good enough. Polio is a highly contagious disease," said Cameron.
"A single person with polio can infect hundreds of people before it is even been identified. If we fail to eradicate polio completely we run the risk that the disease will spread back to the country in which it has been eradicated," he said.
"As long as one child remains at risk all children remain at risk. That is a risk we should not take."
Pakistan's Prime Minister Yasouf Raza Gillani said cross border movements between Afghanistan and Pakistan, and "orthodox and fanatic" militant leaders who refused to allow doctors into their areas, were hindering the fight against polio.
"We are seriously concerned that polio, once eradicated in Pakistan, has resurfaced in the country during the past six to seven years," said Gillani.
In Pakistan recorded 14 new cases in the past week, the highest number of new cases reported in a single week ever. There are currently 132 cases in Pakistan, which has nationwide transmission.
In Nigeria, polio has spread more widely in the past two months than at any time over the last two years.
(This story was corrected in second paragraph to clarify Afghanistan not a member of the Commonwealth)
(Reporting by Michael Perry)