Geneva - Polio has broken out among young children in northeast Syria, the World Health Organisation (WHO) confirmed on Tuesday, and could spread inside and outside the country, where civil war has led to falling vaccination rates.
The highly contagious crippling disease, transmitted via contaminated food and water, can spread rapidly among children under five, especially in unsanitary shelters for the displaced in Syria or crowded refugee camps in neighbouring countries.
Twenty-two children in Deir al-Zor province bordering Iraq became paralysed in October and WHO's regional laboratory in Tunis has isolated the wild polio virus in samples taken from 10 victims. Results and the other 12 are expected within days.
"Out of those 22 being investigated, 10 are now confirmed to be due to polio virus," Oliver Rosenbauer, spokesperson of the WHO polio eradication programme, told a news briefing in Geneva.
Most victims are under two years old and are believed never to have been vaccinated or to have received only a single dose of the oral vaccine instead of the three which ensure protection from polio, he said.
It is Syria's first polio outbreak since 1999, according to the United Nations agency.
"Immunisations have started in that area," Rosenbauer told Reuters, referring to Deir al-Zor.
The city of Deir al-Zor is partially controlled by Syrian government forces while the surrounding countryside is in the hands of rebels fighting to remove President Bashar Assad.
Some 65 000 children under age five in Deir al-Zor province are deemed vulnerable, according to the WHO's latest estimate.
Across Syria there are 3m children who are under the age of 5.
Young children vulnerable
Before the conflict, which began with peaceful protests in March 2011 and led to a civil war, 91% of Syrian children were vaccinated against diseases including polio, but the rate has fallen to about 68%, Rosenbauer said.
"So it makes sense that very young kids would get it."
Polio invades the nervous system and can cause irreversible paralysis within hours.
It is endemic in just three countries (Nigeria, Pakistan and Afghanistan) raising the possibility that foreign fighters imported the virus into Syria, where Islamist militant groups are part of the splintered array battling Assad's forces.
"The next step will be to look genetically at these isolated viruses and see where they came from. That should give some clarity on the origin," Rosenbauer said.