3.4 Phylogenetic analysis of RV
RV subtypes were identified in 32 RV-positive samples representing diverse time points by analyzing the VP4/VP2 partial regions, comparing them with reference strain sequences of RV-A, B, and C found in the Online 10th Report of the International Committee on Taxonomy of Viruses. As shown in figure 3, phylogenetic analysis of the VP2-VP4 region disclosed the presence of three RV species among the positive samples: RV-A, accounting for 46.88% (15 out of 32), RV-B at 6.25% (2 out of 32), and RV-C, also comprising 46.88% (15 out of 32).
Between 2021 and 2023, there were circulation of 23 distinct confirmed RV subtypes found in this study. RV-A was the most diverse species, encompassing 11 different types (RV-A7, 20, 29, 30, 49, 55, 58, 60, 66, 78, 80). The most prevalent genotypes identified were RV-A66, RV-A80, and RV-A20. In the RV-B category, two types were detected: RV-B3 and RV-B37. As for RV-C, ten different types were noted: RV-C5, C6, C13, C15, C17, C18, C27, C32, C40, C42, and C88, with RV-C15, RV-C6, and RV-C13 being the most common (Figure 3). In this investigation, a notable shift in the dominance between RV-A and RV-C was observed. During the period from April to June 2022, RV-A exhibited a higher prevalence, with a ratio of RV-A to RV-C recorded at 4:1. However, in the latter part of the year, specifically between October and December 2022, the pattern shifted notably, with the prevalence ratio adjusting to a more balanced 1:1.33. This variation suggests a dynamic pattern in the circulation and genetic diversity of RV infections among the pediatric population.