Epidemiological and genetic characteristics of human astroviruses detected during acute gastroenteritis outbreaks in Yokohama, Japan, between 2017 and 2023

Abstract

This study aimed to investigate the epidemiological and genetic characteristics of human astroviruses (HAstVs) detected during acute gastroenteritis (AG) outbreaks in Yokohama, Japan. We collected stool samples and epidemiological information between September 2017 and August 2023 and used real-time reverse transcription (RT)-PCR and/or RT-PCR to detect HAstV from 53 samples from 20 (3.1%) of the 648 virus-associated AG outbreaks during the study period. Of the 20 outbreaks investigated via sequencing, 13 were caused by classic HAstV, three by HAstV-MLB, and four were due to multiple genotypes, classic HAstV and HAstV-MLB. The strains detected in Yokohama were found to be closely related within their respective genotypes. The distribution of HAstV genotypes differed by age groups, with HAstV1 and HAstV-MLB1 primarily found in 0–3 year-olds, whereas HAstV4 typically occurred in individuals over 4 years of age. Of the 53 HAstV-infected patients, 49 (92.5%) experienced diarrhea, with 36 exhibiting only this symptom. Vomiting (18.9%) was less prevalent than diarrhea. There were no differences in the symptoms between individuals with classic HAstV and HAstV-MLB.