Human astrovirus (HAstV) is recognized as one of the major causative agents of acute gastroenteritis in children worldwide. Data on the genetic diversity of HAstV in Nigeria are limited. The aim of this study was to determine the prevalence and molecular epidemiology of classical HAstV in children under 5 years of age with acute gastroenteritis in Ogun State, Nigeria. Fecal samples (331) as well as socio-demographic and clinical data were collected across the three senatorial districts of the state from February 2015 to April 2017. One hundred seventy-five samples were randomly selected and analyzed for the presence of HAstV using RT-PCR. PCR amplicons from positive samples were sequenced, and phylogenetic analysis was done to determine genotypes and lineages. The overall prevalence rate was 19.4% (34), with the highest occurrence observed in 2015 (41.4%). Viral coinfections were detected in 13 cases (38.2%). HAstV infection occurred throughout the year and in all age groups, mainly in the age group of 0-12 months. There was significant association between prevalence rate and collection year; however, no association was observed with gender, age, symptoms or risk factors. HAstV-5 was the predominant genotype (76.5%) circulating throughout the study period, followed by HAstV-1 (23.5%), which circulated only in the first 2 years of the study. Phylogenetic analysis showed that all HAstV-5 strains detected belonged to the 5a lineage, while HAstV-1 strains were grouped into lineage 1b. This study, to the best of our knowledge, is the first comprehensive report on molecular characterization of classical HAstV among children with gastroenteritis in the country, and this will serve as baseline information for implementing appropriate infection control practices.

人类星状病毒（HAstV）被公认为全球儿童急性胃肠炎的主要病原体之一。尼日利亚HAstV的遗传多样性数据有限。本研究的目的是确定尼日利亚奥贡州 5 岁以下急性胃肠炎儿童中经典 HAstV 的流行率和分子流行病学。从 2015 年 2 月至 2017 年 4 月，在该州的三个参议院区收集了粪便样本 (331) 以及社会人口和临床数据。随机选择了 175 个样本并使用 RT-分析了 HAstV 的存在。聚合酶链反应。对阳性样品的 PCR 扩增子进行测序，并进行系统发育分析以确定基因型和谱系。总患病率为 19.4% (34)，2015 年观察到的最高发生率（41.4%）。在 13 例 (38.2%) 中检测到病毒合并感染。HAstV感染发生在全年和所有年龄组，主要发生在0-12个月的年龄组。患病率与采集年份显着相关；然而，没有观察到与性别、年龄、症状或风险因素有关。HAstV-5 是整个研究期间流行的主要基因型（76.5%），其次是 HAstV-1（23.5%），仅在研究的前 2 年流行。系统发育分析表明，检测到的所有HAstV-5菌株均属于5a谱系，而HAstV-1菌株则归入1b谱系。据我们所知，这项研究，