Detection of Human Parechoviruses in Clinical and Municipal Wastewater Samples in Miyagi, Japan, in 2012-2014

In order to study the epidemiology of human parechovirus (HPeV) infections and to evaluate the feasibility of environmental surveillance, we analyzed 281 stool samples, 265 nasopharyngeal swab samples, and 79 municipal wastewater samples for HPeV. The samples were collected in Miyagi Prefecture, Japan, between April 2012 and March 2014. HPeV was detected by reverse-transcription-PCR targeting the partial 5'-untranslated region and was genotyped by sequencing the capsid VP1 region. Seven stool samples (2.5%) and 1 nasopharyngeal swab sample (0.4%), all of which were from children under 2 years old, and 14 wastewater samples (18%) were positive for HPeV. Clear seasonality was observed: all positive samples were collected between July and December during the study period. All strains detected in the stool and wastewater samples had genotype HPeV1, and the strain from the nasopharyngeal swab sample had genotype HPeV6. A phylogenetic analysis revealed that all HPeV1 strains from the stool samples cluster together with those from the wastewater samples, indicating that the HPeV1 strains circulating in human populations can also be detected in municipal wastewater.