Relative frequency and type identification of non-polio enteroviruses isolated from acute flaccid paralysis cases in Iran, 1995-2000

Iran National Polio Laboratory (NPL) is a member of the World Health Organization (WHO) Polio Laboratories Network. NPL receives stool specimens from acute flaccid paralysis (AFP) cases from all the provinces throughout Iran for poliovirus detection and identification. Furthermore, the NPL also detects non-polio enteroviruses (NPEVs) in these specimens. Recently, NPEVs have come to be believed to be one of the most important causes of AFP following wild poliovirus. This paper reports the prevalence of different types of NPEVs isolated from the specimens of AFP cases between 1995 and 2000. Stool collection, virus detection and serotype identification were performed according to the WHO standard procedures. A total of 2180 stool specimens from AFP cases were received at the National Polio Laboratory. Coxsackie B viruse and echoviruses 6, 11, 7 and 13 had the highest frequency, identified in 23.7%, 14.4%, 12.7%, 11% and 10.2% of the NPEVs isolated from AFP cases, respectively. Four cases of echovirus 20 were identified, in 2 cases the patiets having died and in one the patient having been afflicted with residual paralysis. There have been no reports of death or residual paralysis (paralysis continuing after 60 days) due to echoviruse 20. Considering the upward trend of AFP cases in Iran, even after wild poliovirus eradication, studies are needed to determine the frequency and type identification of NPEVs and the relationship between NPEVs and residual paralysis in the post-eradication era (2000 onwards).