Sequence analysis of Vietnamese P[6] rotavirus strains suggests evidence of interspecies transmission

Nucleotide and amino acid sequences of the VP8* gene of five Vietnamese P6] rotavirus strains detected from hospitalized patients with acute gastroenteritis were analyzed and compared with other human and porcine P6] rotaviruses. It is of interest that these strains had greatest identity with two Italian porcine rotavirus strains, 134/04-10 and 134/04-11. To our knowledge, these five Vietnamese rotaviruses are the rare P6] rotavirus strains belonging to lineage I that cluster into sublineage Ic with porcine rotaviruses, and not into sublineage Ia, as other human P6] rotaviruses have done so far. Sequence analysis of the VP7 gene of these P6] rotavirus strains was also performed. The results showed that the Vietnamese G9P6] strain had high similarity with other human G9 rotaviruses, confirming a human-animal reassortant virus, whereas other three G4P6] strains had best identity with porcine G4 rotavirus strains, suggesting interspecies transmission of rotavirus between porcine and humans. This result provides the important data on molecular characteristics of Vietnamese rotaviruses, and highlights interspecies transmission events of rotaviruses in Vietnam as well as in Asia.