A new study revealed that the polio outbreak in Syria threatens to reach Europe due to "silent transmission."
Doctors in Germany namely Dr. Martin Eichner, a professor at the University of Tubingen and Dr. Stefan Brockmann, of Reutlingen Regional Public Health Office, said that the poliovirus in Syria may put its neighboring regions at high risk.
The doctors also said that in countries like Austria and Ukraine, where polio vaccine coverage is very low, 83 percent and 95 percent respectively, an outbreak is nearly possible especially when refugees fly to these countries.
They have raised the warning because only one in 200 polio patients may develop paralysis and it may take a year before an epidemic is discovered. People may be infected due to "silent transmission" wherein those affected does not show symptoms of the illness yet they have the virus stored in their intestines. By the time the carrier finds out that he is infected, thousands may have been infected already.
Eichner and Brockmann said that majority of the countries in Europe administer inactivated polio vaccine (IPV) and not the live oral polio vaccine (OPV) because they believe that, in odd cases, OPV can cause acute flaccid paralysis -- the main symptom of polio. However, OPV drops give higher protection against poliovirus, whereas IPV, though highly effective at preventing polio disease, may need very high vaccination coverage.
Israel can also pose a potential threat, said the doctors.
"Wild poliovirus has also been found in sewage in Israel and from samples taken from some symptom-free individuals since February 2013. Although there have been no cases of polio in Israel, tourists could risk bringing the infection to other countries," Eichner told BBC.
"The WHO wants to get rid of polio completely and had got pretty close until recent outbreaks. The fact that most of those infected do not display symptoms but can still spread the disease makes it a very hard virus to get rid of as it is like fighting an invisible enemy," added Eichner.
About 322 cases of wild poliovirus have been confirmed, as of this year and more than 50 percent of them are noted in Somalia.
The study was published on the Nov. 8 issue of the online journal The Lancet.
