The World Health Organization is investigating a cluster of possible polio cases in an eastern province of Syria.
If the cases are confirmed, they'd be the first ones in the war-torn nation in more than a decade. The country eliminated polio in 1999.
Syria used to have one of the highest polio vaccination rates in the region. If the virus has returned, it would be a high-profile example of the ramifications of the collapse of Syria's once-vaunted public health system.
Initial tests from the Syrian national laboratory in Damascus suggested that polio has crippled two children in the east, the WHO said Saturday. Further laboratory tests related to the cases are underway at the WHO's regional offices.
"We still need final confirmation from a laboratory, but all the indicators show that this is polio," Oliver Rosenbawer from the Global Polio Eradication Initiative told The Telegraph on Sunday.
The Syrian Ministry of Health says that it's treating the cases as part of a polio outbreak and beginning emergency vaccination campaigns in the area. The cluster of paralysis cases is in the eastern province of Deir Ezzor, which straddles the Euphrates River. That river flows east from Syria across Iraq.
Over the last two decades, the world has nearly eradicated polio.
There were only 223 cases recorded globally in 2012, and they were all from remote areas of Nigeria, Afghanistan and Pakistan.
This year, there have been 296 cases worldwide, but more than half of them have been in Somalia, which had eliminated polio in 2007.
Before the civil war broke out in Syria in 2011, the WHO estimated that 83 percent of Syrian children were fully vaccinated against polio. By 2012 that vaccination rate had fallen to 52 percent.
The WHO has issued a regional polio surveillance alert in response to the cases from Syria. It is urging neighboring countries to launch supplementary polio vaccination campaigns to keep the virus from spreading.
In September, Israel underwent an emergency immunization drive after polio appeared in sewers around the country. The campaign aimed to give polio boosters to 1 million children under the age of 9.
But carrying out such vaccination campaigns in Syria amid the ongoing civil war, however, could prove very difficult.