Acute gastroenteritis outbreaks caused by human astrovirus, 1978-2021: A systematic review.

Human astrovirus (HAstV) is one of the main pathogens that cause sporadic cases of acute gastroenteritis, sometimes leading to outbreaks. This study aimed to elucidate the epidemiological and etiological characteristics of HAstV outbreaks worldwide. Literature on HAstV outbreaks published before January 2022 was retrieved from the China National Knowledge Infrastructure, WanFang, WeiPu, PubMed, and Web of Science databases. Date, region, population, settings, transmission modes, clinical symptoms, and etiological characteristics of the outbreaks were collected and analyzed. Thirty-one articles on 32 HAstV outbreaks reported between November 1978 and October 2018 were included. The outbreaks mainly occurred in autumn (14/32, 43.75%), and more of them were reported in 1996, 2004, and 2017. Outbreaks were primarily distributed in the Northern Hemisphere and mainly occurred in nursery centers and kindergartens (9/29, 31.03%), hospitals (5/29, 17.24%), and schools (4/29, 13.79%). Viral genotypes were identified during 19 outbreaks, and HAstV-1 was predominant (8/19, 42.10%). Eleven outbreaks were caused by mixed infection, and norovirus (9/11, 81.82%) and rotavirus (5/11, 45.45%) were the most common mixed pathogens. The transmission routes were reported in 9 outbreaks of mixed infection, and most (7/9) were related to waterborne and foodborne transmission. Although HAstV outbreaks are infrequently reported, it is necessary to consider HAstV in norovirus-negative gastroenteritis outbreaks. In addition, local Centers for Disease Control and Prevention should have the capacity to handle HAstV outbreaks and identify pathogens.