Molecular detection and genetic diversity of rotavirus a in domestic dogs and cats in Bangkok, Thailand

Rotavirus A (RVA) in one of the important pathogens causing gastroenteritis in humans and many animal species. The zoonotic potential of RVA has been reported and raises major concerns, especially in high animal-human interfaces settings. The objectives of this thesis were to determine the occurrence of RVAs in dogs and cats, and to investigate the genetic diversity and genetic relationship among RVAs in dogs, cats, human, and other animal species. The total of 572 rectal swab samples were collected from dogs and cats in animal hospitals, in Bangkok and vicinities, during January 2020 to June 2021. The conventional one-step RT-PCR result showed 1.92% (11/572) occurrence of RVAs in dogs and cats, which by species were 2.75% (8/290) in dogs, and 1.06% (3/282) in cats. Age of animals might be the risk factor affecting the occurrence of RVAs in dogs, but the result in cats is still inconclusive. Besides, our finding is the first report of rotavirus A in cats in Thailand. To characterize the viruses, two canine rotavirus A (CRVA) and one feline rotavirus A (FRVA) were subjected to whole genome sequencing by nanopore sequencing. Our results showed all 3 viruses were classified as RVA genotype G3P[3]. Genetic constellation of RVAs, CRVAs had G3-P[3]-I3-R3-C3-M3-A9-N2-T3-E3-H6 genotype, while FRVA had G3-P[3]-I8-R3-C3-M3-A9-N3-T3-E3-H6 genotype. Notably, RVAs in this study had the AU-1 genetic constellation backbone with reassortment. The results of genetic analysis showed that CRVAs were closely related and had high nucleotide identities to CRVAs from previous reported in Thailand, except VP6 gene and NSP3 gene which were closely related to RVAs in human and cat, respectively. The result of bootscan analysis supported the possible reassortment of RVAs from dog, human, and cat in the CRVAs. While FRVA in this study was closely related and had high nucleotide identities to RVAs in human, bat, and simian. The result of bootscan analysis also supported the possible reassortment of this FRVA. Meanwhile, none of any segments of this FRVA were closely related to cat’s reference strain, indicating possible interspecies transmission of FRVA in intermediate animal species to cat, and the reassortment event of RVAs from human, bat, and simian had occurred in that intermediate animal species. In conclusion, this study provided the occurrence of RVAs in dogs and cats, and suggesting the possible multiple reassortment, interspecies transmission, as well as zoonotic potential of the viruses. The public health awareness should be raised due to the zoonotic potential of CRVA and FRVA. RVAs studies in larger scale in dogs and cats in Thailand should be considered to determine the dynamic and distribution of the viruses. In addition, the studies of RVAs in bats, simian, and other wildlife species should be performed to analyze the origin and evolution of RVAs in the future.