To many Europeans, poliomyelitis is an ancient foe. But for the first time in years, there is a risk that the crippling paralytic disease is about to make an unwelcome return. Poliovirus has re-emerged on Europe’s southeastern flank — in Israel and Syria — leaving public-health officials concerned that the disease could be imported and again become established on the continent.
Europe is surprisingly vulnerable. The World Health Organization (WHO) declared its European region, which now spans 53 countries from Portugal to Russia, free of polio in 2002. But many countries have since dropped their guard. Surveillance systems are often incomplete and of poor quality, and suboptimal vaccination rates mean that many countries, including the United Kingdom and Germany, are considered to be susceptible to outbreaks sparked by imported cases1, 2 (see ‘Polio threat’).
The situation is “a wake up call”, says Marc Sprenger, director of the European Centre for Disease Prevention and Control (ECDC) in Stockholm. Given the weaknesses in European polio defences, the extensive levels of travel between Europe and Israel, and the millions of refugees fleeing Syria, the ECDC thinks that there is a real risk of outbreaks in the European Union (EU). Member states are taking the threat of import “extremely seriously”, Sprenger adds.
The effort to eradicate polio has made great strides since the launch of the Global Polio Eradication Initiative in 1988. Then, 350,000 children were paralysed annually in 125 countries. That toll has been slashed in the past 25 years by more than 99%, with just 223 cases last year. Polio is now endemic in only three countries: Afghanistan, Nigeria and Pakistan. Sporadic imported cases continue to occur, however, particularly in Africa, with a Somalian outbreak causing 174 cases so far this year.
The latest threat emerged on 19 October, when the WHO reported a cluster of cases of acute flaccid paralysis — a classic polio symptom — in Deir-ez-Zor, a conflict-ridden province in eastern Syria. Two of the 22 cases were confirmed as polio by national authorities, and on 29 October, the WHO confirmed a total of ten. Officials had assumed the worst. “Everyone is moving to outbreak-response mode,” Oliver Rosenbauer, a spokesman for the Global Polio Eradication Initiative at WHO in Geneva, Switzerland, told Nature last week.