The World Health Organization (WHO) has confirmed that the polio that has crippled at least 13 children in Syria originated in Pakistan according to Reuters .
Genetic sequencing has revealed that the strain found in Syrian children  in Deir al-Zor was linked to the strain found in sewage in Israel, the Palestinian territories and Egypt, which in turn was linked to the strain of wild poliovirus circulating in Pakistan.
However, no polio has been reported in Israel, the Palestinian territories or Egypt due to the high degree of immunization in these countries.
Polio is endemic in three countries in the world: Pakistan, Afghanistan and Nigeria.
Islamic fighters from Pakistan who are fighting President Bashar Al-Assad’s regime in Syria are thought to have spread the disease. Following the outbreak of civil war , polio immunization rates in Syria have dropped from 90% to 68%.