Molecular Prevalence of Human Astrovirus Among Children Under Five Years of Age With Gastroenteritis in Ilorin Metropolis, North‐Central Nigeria: A Cross‐Sectional Study

ABSTRACT Background and Aims Human astrovirus (HAstV) is a recognized cause of viral gastroenteritis, however, data from north‐central Nigeria remain limited. This study aimed to determine the prevalence of classic HAstV RNA and explore associated factors among children under 5 years presenting with gastroenteritis in Ilorin, Nigeria. Methods This hospital‐based cross‐sectional study was conducted from May 2025 to September 2025 among 200 children aged 13–59 months attending selected hospitals in Ilorin who presented consecutively. Stool samples were collected and analyzed using real‐time reverse transcription polymerase chain reaction for classic HAstV RNA. Data were analyzed using R software. Participant characteristics were summarized descriptively, prevalence estimates were calculated with exact 95% confidence intervals, and associations with astrovirus detection were evaluated using Fisher's exact test, the Wilcoxon rank‐sum test, and Firth penalized logistic regression. Results Classic HAstV RNA was detected in 4 of 200 children under 5 years with acute gastroenteritis, giving an overall prevalence of 2.0% (4/200; 95% CI: 0.55%–5.04%). Prevalence was highest among children aged 49–60 months (2.94%), males (2.50%), rural residents (2.33%), users of borehole/well water (2.86%), and children attending daycare (4.0%). All astrovirus‐positive children presented with vomiting, moderate dehydration, resided in rural communities, had animal contact, used borehole/well water, and received oral rehydration solution. No other characteristics were significantly associated with HAstV. Feeding method was the only factor significantly associated with detection (p = 0.03), with the highest prevalence among exclusively breastfed children (33.3%; 2/6). However, wide confidence intervals around both the raw prevalence and the adjusted odds ratio (aOR = 0.01; 95% CI: 0.00–0.29) indicate this finding is exploratory rather than confirmed, warranting confirmation in larger studies. Conclusion Astrovirus in this population is relatively low; however, it remains epidemiologically important, particularly as prevalence may vary with season. Continued surveillance and further molecular characterization are warranted.