Prevalence and genetic diversity of porcine rotavirus A from diarrheic piglets in Northern Thailand

Background: Rotavirus A (RVA) is an important pathogen causing acute viral gastroenteritis in young children and various animals. RVA is also recognized as a common cause of gastroenteritis in piglets. Epidemiological studies of porcine RVA (PoRVA) conducted in different settings worldwide reported that the prevalence of PoRVA infection ranged from 9.4% to 74.0% with the predominance of G4P[6], G4P[7], and G5P[7] genotypes. In Thailand, long-term epidemiological surveillance of PoRVA infection is limited. Continuous monitoring of PoRVA infection is required to gain a better understanding the prevalence and evolution of PoRVA. In this study, the prevalence and genetic diversity of PoRVA were investigated by screening of 1,260 stool samples collected from 0 to 5-week-old piglets with acute diarrhea during 2016 to 2023 by using real-time RT-PCR. The G- and P-genotypes of RVA were identified by characterization of the partial VP7 and VP4 genes by using multiplex-PCR, nucleotide sequencing, and phylogenetic analysis. Results: A total of 303 out of 1,260 (24.0%) samples were positive for PoRVA. Overall, the G5P[23] (28.7%) and G4P[23] (28.4%) were detected as the co-predominant PoRVA genotypes, followed by G5P[13] (9.9%), G3P[23] (9.6%), G9P[23] (8.2%), G4P[13] (7.9%), G9P[13] (3.3%), G3P[13] (1.7%), G4P[6] (1.7%), and G2P[23] (0.3%) genotypes. Additionally, a rare G2P[27] (0.3%) genotype re-emerged approximately 22 years after the initial detection in 2000 in Chiang Mai, Thailand. Conclusion: Our results revealed the prevalence of wide variety of PoRVA genotypes circulating in piglets with acute diarrhea in Thailand over a study period of seven years. Of these, G5P[23] and G4P[23] emerged as the most predominant genotypes, which were substantially different from previous reports in the same geographical area. The findings offer valuable contribution to a better understanding of molecular epidemiology and evolution of PoRVA in piglets with acute diarrhea.