The number of poliomyelitis (polio) cases outside the three endemic countries (Nigeria, Pakistan and Afghanistan) increased in 2013 compared to 2012, including a recent outbreak in war-torn Syria. Israel has not seen any paralytic infections but has found evidence of the disease in environmental samples at 25 separate sites. Polio does not have a lasting impact on a large portion of the population. In 1988, before the disease was widely eradicated, there were 350,000 cases of polio-associated paralysis. In fact, most people infected with the virus are asymptomatic; only one in 200 infected individuals will experience paralysis. However, the disease targets children, and the lasting effects of paralysis on a child give the disease a disproportionally large psychological impact.
Polio cases around the world decreased from 1,652 reported cases in 2008 to only 223 reported cases in 2012. Almost all of the cases in 2012 occurred in Afghanistan, Pakistan and Nigeria, where the disease remains endemic. However, reported infections in 2013 have already reached 341, with 218 cases occurring in non-endemic countries. The largest concentration of these infections has been in Somalia, where the risk of reoccurrence is high due to low immunization rates (caused by instability in the country, poor infrastructure and al Shabaab's movement against vaccinations) and its geographic proximity to Africa's poliovirus importation belt, which stretches from Nigeria to the Horn of Africa. Outside eastern Africa, the highest number of infections for non-endemic countries occurred in Syria, with 13 confirmed cases and more cases suspected. The source of the Syrian outbreak has been traced back to Pakistan. Immunization rates in Syria have decreased substantially since the start of the civil war, leaving a growing population of unvaccinated individuals, primarily children.
Israel, with a far more robust public health system than Syria and Somalia, has also seen evidence of the virus. Israel has an immunization rate of more than 95 percent and, like much of the developed world, uses the inactivated poliovirus form of the vaccine, which provides immunity for the vaccinated individual but is less effective than the oral vaccine at blocking transmission of the virus, leaving unvaccinated individuals at risk. The inactivated poliovirus vaccination does remove the risk of vaccine-derived infections, which remain rare with the oral form of the vaccine. While Israel has implemented additional vaccination campaigns, including reintroducing the oral form of the vaccine and administering it to children under the age of 10, the silent spread of the disease throughout the country thus far illustrates the potential risks for transmission in the developed world in an era of increased globalization.
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