Epidemiological Surveillance: Genetic Diversity of Rotavirus Group A in the Pearl River Delta, Guangdong, China in 2019.

Objective: This study aimed to understand the epidemic status and phylogenetic relationships of rotavirus group A (RVA) in the Pearl River Delta region of Guangdong Province, China.

Methods: This study included individuals aged 28 days-85 years. A total of 706 stool samples from patients with acute gastroenteritis collected between January 2019 and January 2020 were analyzed for 17 causative pathogens, including RVA, using a Gastrointestinal Pathogen Panel, followed by genotyping, virus isolation, and complete sequencing to assess the genetic diversity of RVA.

Results: The overall RVA infection rate was 14.59% (103/706), with an irregular epidemiological pattern. The proportion of co-infection with RVA and other pathogens was 39.81% (41/103). Acute gastroenteritis is highly prevalent in young children aged 0-1 year, and RVA is the key pathogen circulating in patients 6-10 months of age with diarrhea. G9P[8] (58.25%, 60/103) was found to be the predominant genotype in the RVA strains, and the 41 RVA-positive strains that were successfully sequenced belonged to three different RVA genotypes in the phylogenetic analysis. Recombination analysis showed that gene reassortment events, selection pressure, codon usage bias, gene polymorphism, and post-translational modifications (PTMs) occurred in the G9P[8] and G3P[8] strains.

Conclusion: This study provides molecular evidence of RVA prevalence in the Pearl River Delta region of China, further enriching the existing information on its genetics and evolutionary characteristics and suggesting the emergence of genetic diversity. Strengthening the surveillance of genotypic changes and gene reassortment in RVA strains is essential for further research and a better understanding of strain variations for further vaccine development.