Sapovirus in Water, Japan

Abstract

Sapoviruses are etiologic agents of human gastroen- teritis. We detected sapovirus in untreated wastewater, treated wastewater, and a river in Japan. A total of 7 of 69 water samples were positive by reverse transcription-PCR. Phylogenetic analysis of the viral capsid gene grouped these strains into 4 genetic clusters. T he family Caliciviridae contains 4 genera, Sapovirus, Norovirus, Lagovirus, and Vesivirus, which include sapovirus (SaV), norovirus (NoV), rabbit hemorrhagic dis- ease virus, and feline calicivirus strains, respectively. SaV and NoV are agents of human gastroenteritis. The most widely used method of detection is reverse transcription-PCR (RT-PCR), which has a high sensitivity and can also be used for genetic analysis. Only a limited number of SaV studies have been conducted, although most studies have shown that SaV infections are more fre- quent in young children than in adults and that nearly all children are infected by 5 years of age. NoVs have been detected in oysters (and other shell- fish), water from drinking fountains, ice, and community drinking water (1-4). Environmental studies of SaV have not been conducted. SaV strains can be divided into 5 genogroups (GI-GV), among which GI, GII, GIV, and GV infect humans; GIII infects porcine species. Phylogenetic studies have also designated SaV clusters or genotypes to further describe strains that differ by ≈10% in nucleotide or amino acid sequences. The purpose of this study was to identify and describe SaV strains in environmental sam- ples, namely, untreated wastewater, treated wastewater, a river, and seawater, in Japan. The Study