Presence and environmental circulation of enteric viruses in three different wastewater treatment plants

AIMS: The aim of the work was to evaluate the circulation of the viruses and to determine a correlation between faecal indicators and viruses. METHODS AND RESULTS: Raw wastewater and effluent samples were collected from three wastewater treatment plants, during three sampling periods, and analysed, using cultural and molecular methods, to determine bacteria and virus presence. The results show a removal of bacterial indicators, but a limited reduction of the phages. The viral analysis displays the circulation of cultivable enteroviruses and differences in the seasonal-geographical distribution. Hepatitis A virus was found with only two genotypes: IA-IB. Rotavirus was present in 11.11%, 24.14%, 2.78% of the samples in the 1st, 2nd and 3rd sampling periods; Astrovirus in 33.33%, 6.9%, 25%; Adenovirus in 7.41%, 3.45%, 2.78%; Norovirus in 7.41%, 10.34%, 5.56% respectively. Adenovirus was never identified in plants B and C as Rotavirus in plant C. CONCLUSIONS: The presence of faecal indicators was not predictive of the enteric virus presence, whereas a different circulation of Enteroviruses was found in the wastewater treatment plants. SIGNIFICANCE AND IMPACT OF THE STUDY: The study shows the importance and the usefulness of molecular methods to evaluate the virus circulation and the genetic variability of Enteroviruses.