Genetic characterization of rotavirus A strains circulating in children under 5 years of age with acute gastroenteritis in Tehran, Iran, in 2023–2024: dissemination of the emerging equine-like G3P[8]-I2-E2 DS-1-like strains

The present study was conducted to monitor the genotype diversity of circulating species A rotavirus (RVA) in Iran. A total of 300 faecal specimens were collected from children under 5 years of age hospitalized for acute gastroenteritis between October 2023 and October 2024. G3P[8] represented 72.91% (70/96) of all RVA-positive samples, further subdivided into equine-like G3P[8]-I2-E2 DS-1-like and human G3P[8]-I1-E1 Wa-like. A retrospective genetic analysis of G3P[8] strains isolated from 2015 to 2017 was also performed and showed that G3P[8] strains belong to the G3P[8]-E1-I1 Wa-like genetic pattern, which is typically similar to human G3P[8] Wa-like strains in this study. The emergence of equine-like G3P[8] DS-1-like strains in Iran may not be related to selection pressure from rotavirus vaccination, but rather to cross-border migration of rotavirus strains due to population movements.