Detection of enteroviruses from urban sewage in Parma

The human enteroviruses (EV) are the most common and widespread human viruses in the world. They have bowel as their natural habitat and they can spread in the environment through the faecal excretion. In the continental climate Regions these viruses may cause epidemic outbreaks in summer and fall, while in the tropical Regions the EV infections present a high incidence during all year. The symptoms can be minor or subclinic, but they can be also associated to rare and serious diseases. The aim of this study was to evaluate the environmental circulation of polioviruses and non-polio enteroviruses (NPEV) using standard methods of urban wastewater surveillance recommended by the WHO.

A total of 188 wastewater samples were collected between February 2005 and December 2008 from two sewage treatment plants in Parma. The sampling was carried out twice a month. Environmental variables were collected for each day of sampling.

Out of the 188 examined wastewater samples, 78.7% were positive to the enterovirus research. One out of the 148 positive samples was identified as poliovirus Sabin-like type 3. The remaining 147 positive samples were enteroviruses non polio: Coxsakieviruses and Echoviruses. All Coxsakieviruses isolated were of type B.

The proposed method has shown high sensibility, also in presence of very low expected prevalence of vaccine poliovirus. It allows to verify the kind and relative frequency of enteric viruses circulating in the country, whose characteristics (virulence and pathogenicity) may vary with reference to a different epidemiologic and demographic structure of the resident population.