Temporal variations in genotype distribution of human sapoviruses and Aichi virus 1 in wastewater in Southern Arizona, United States

Aims To investigate the molecular epidemiology, especially temporal variations in genotype distribution, of sapoviruses and Aichi virus 1 (AiV‐1) in Arizona, United States, by examining wastewater. Methods and Results A total of 26 wastewater samples (13 influent and 13 effluent) were collected monthly from a wastewater treatment plant and viral strains were identified through nested reverse transcription‐PCR followed by cloning and sequencing analysis. Identified sapovirus strains were classified into seven genotypes belonging to three genogroups (GI, GII, and GV): GI.1, GI.2, GI.3, GII.1, GII.2, GII.8 and GV.1, with a clear temporal shift. The majority of AiV‐1 strains identified from the wastewater samples were classified into genotype B, and genotype A strains were identified in only two samples. Conclusions We identified a number of sapovirus and AiV‐1 strains belonging to multiple genotypes in wastewater samples collected over a 13‐month period. Our results suggested a temporal shift in prevalent genotypes in the community. Significance and Impact of the Study This is the first study elucidating the genotype distribution of human sapoviruses and AiV‐1 in wastewater in the United States. Wastewater surveillance is especially useful for understanding molecular epidemiology of viruses that are less commonly tested in clinical diagnosis, including sapoviruses and AiV‐1.