The exact evolutionary patterns of human G4P rotavirus strains remain to be elucidated. Such strains possess unique and strain-specific genotype constellations, raising the question of whether G4P strains are primarily transmitted via independent interspecies transmission or human-to-human transmission after interspecies transmission. Two G4P rotavirus strains were identified in fecal specimens from hospitalized patients with severe diarrhea in Thailand, namely, DU2014-259 (RVA/Human-wt/THA/DU2014-259/2014/G4P) and PK2015-1-0001 (RVA/Human-wt/THA/PK2015-1-0001/2015/G4P). Here, we analyzed the full genomes of the two human G4P strains, which provided the opportunity to study and confirm their evolutionary origin. On whole genome analysis, both strains exhibited a unique Wa-like genotype constellation of G4-P-I1-R1-C1-M1-A8-N1-T1-E1-H1. The NSP1 genotype A8 is commonly found in porcine rotavirus strains. Furthermore, on phylogenetic analysis, each of the 11 genes of strains DU2014-259 and PK2015-1-0001 appeared to be of porcine origin. On the other hand, the two study strains consistently formed distinct clusters for nine of the 11 gene segments (VP4, VP6, VP1-VP3, and NSP2-NSP5), strongly indicating the occurrence of independent porcine-to-human interspecies transmission events. Our observations provide important insights into the origin of zoonotic G4P strains, and into the dynamic interaction between porcine and human rotavirus strains.
All Science Journal Classification (ASJC) codes
- Molecular Biology