Surveillance for rat hepatitis E in wastewater networks, Italy.

Rat hepevirus is an emerging zoonotic pathogen associated with human hepatitis and distantly related to the hepatitis E virus. By using broadly reactive primers for hepevirus, we detected viral RNA in 68/155 (43.9%) of sewage specimens collected from 14 wastewater treatment plants serving about half of the population of Abruzzo, Italy. On sequence analysis, the 68 strains showed 79.0%-91.6% identities to reference sequences of rodent and human origin, segregating in different genetic groups with a clear geographic/wastewater treatment plant (WWTP)-related pattern.IMPORTANCEHepatitis E virus (HEV) infection constitutes a significant health problem worldwide. In recent years, in addition to the zoonotic HEV3 and HEV4, emerging highly divergent hepevirus of rat origin (rat HEV [RHEV]) has been associated with human acute and chronic hepatitis. As environmental surveillance can be a complementary tool to explore emerging viruses of human and rodent origin, we investigated the epidemiology and the genetic variability of RHEV targeting 14 wastewater treatment plants in an Italian geographic area considered a hot spot for HEV infection in humans. Our results revealed that RHEV is a significant component of the wastewater microbiota with viral RNA detected in 43.9% of the specimens tested, adding further evidence to the need to investigate more in depth the real burden of RHEV infections in humans.