A once-eradicated virus has sickened at least 10 children and babies in war-torn Syria, according to United Nations officials tracking the outbreak.
Reports of acute flaccid paralysis – a telltale sign of polio – began to surface earlier this month in the country's heavily contested Deir Al Zour province. Tests have now confirmed the infection in 10 of 22 suspected cases, most of which involve children aged 2 years or younger, according to a World Health Organization spokesman Oliver Rosenbauer.
"We will run an outbreak response immunization program, not just in the affected area but right across Syria and in seven neighboring countries," said Rosenbauer, describing a six-month emergency vaccination effort aimed at protecting under-immunized children.
Read more about the early signs of the outbreak.
Polio was last seen in Syria in 1999, but the civil war has hindered vaccination efforts. And because the virus is endemic in Nigeria, Pakistan and Afghanistan, it can easily be imported, according to Dr. William Schaffner, an infectious disease expert and chair of prevention at Vanderbilt University Medical Center in Nashville, Tenn.
"People who carry the virus in their intestinal tracts can transmit it, either person-to-person or through contaminated water systems," said Schaffner, explaining how polio lives in the gut but can invade the blood stream and attack the spinal cord to cause permanent paralysis in one of every 200 people infected.
"The treatment, unfortunately, is entirely symptomatic," said Schaffner, noting that the virus usually causes paralysis on one side of the body. "You care for the patient until the infection runs its course. We don't have an antiviral treatment for polio."
While there's no treatment, there is a polio vaccine. The Global Polio Eradication Initiative, a 1988 effort to eliminate the virus through vaccination, led to a 99 percent drop in polio cases worldwide from 350,000 to 223 in 2012, according to WHO.
Syria's susceptibility to viruses because of its stunted vaccination program was highlighted in an open letter published in the September issue of The Lancet.
"In some areas, children born since the conflict started have had no vaccinations, meaning that conditions for an epidemic, which have no respect for national borders, are ripe," a group of doctors wrote, pleading for medical neutrality in the region. "The number of people requiring medical assistance is increasing exponentially, as a direct result of conflict and indirectly because of the deterioration of a once-sophisticated public health system and the lack of adequate curative and preventive care."
Schaffner said the possibility of polio in Syria is tragic, but not unexpected.
"Whenever you have this kind of domestic turmoil and your vaccination programs are interrupted, you have a growing population of children just waiting to have polio reintroduced," he said, adding that the only way to rid a country of polio again is to "start over" with a vaccination program. "And obviously in a time of conflict, that becomes next to impossible."
WHO's Rosenbauer said the emergency response could take longer than six months depending on the course of the conflict and the extent of the outbreak, noting that a similar effort launched in May 2013 in the Horn of Africa – an area with its own pockets of civil unrest – has just started to pay off.
"The results are encouraging but we're not yet done," he said.
The Associated Press contributed to this story.