Molecular epidemiological analysis of enteroviruses in respiratory infection cases in Huzhou, China

Background Enteroviruses are one of the important pathogens causing respiratory tract infections. Moreover, there are many serotypes of enteroviruses, and a single virus type can cause multiple diseases, placing a burden on society and families. This study investigated the infection status and genotypes of enteroviruses in respiratory tract infection cases in Huzhou, China, from January 2024 to December 2025. Methods Nasopharyngeal swabs, nasal wash fluids, or combined nasopharyngeal/oropharyngeal swab samples were collected from patients with influenza-like illness (ILI) and severe acute respiratory infection (SARI) in Huzhou from January 2024 to December 2025. Enterovirus RNA was detected using real-time reverse transcription polymerase chain reaction (real-time RT-PCR). The VP1 gene of enteroviruses was amplified and sequenced, and the sequences were analyzed using MEGA software (version 7.0). Epidemiological data were analyzed using Microsoft Excel 2010 and SPSS software (version 22.0). Results A total of 6,512 patients with respiratory tract infections were enrolled, of which 137 (2.10%) tested positive for enterovirus RNA from 2024 to 2025. Enterovirus-positive cases were mainly concentrated in children under 17 years of age, accounting for 52.55% of all positive cases. Enterovirus infections were predominantly observed in summer and autumn, with a peak in July. VP1 gene sequence analysis of 29 enterovirus strains revealed that the circulating genotypes in Huzhou comprised 10 serotypes belonging to three groups (A, B, and D), among which CV-A4 and CV-A2 were the dominant serotypes. Conclusions Enteroviruses are important pathogens of respiratory tract infections in Huzhou, with a high incidence in summer and autumn among patients under 17 years of age. The transmission of respiratory enteroviruses in this region shows a certain degree of genetic diversity.