GENEVA — While many of Pakistan's neighbors have recently been able to declare themselves polio free, the country is struggling itself with eradicating the virus. The World Health Organization warned Monday that even areas of Pakistan that were free of the virus are now being re-infected. "As long as polio remains anywhere in the world, polio-free countries everywhere will continue to be at risk of re-infection. This virus has shown again that it can find susceptible children anywhere," said Tarik Jasarevic, a World Health Organization spokesperson.Jasarevic said the best way for countries to protect themselves and minimize the risk and consequences of being re-infected is to maintain very high levels of vaccination coverage, strong disease surveillance, and implement relevant recommendations for travellers.Pakistan, Cameroon, and the Syrian Arab Republic pose the greatest risk of spreading poliovirus abroad in 2014.