Full genome characterization of a porcine-like human G9P[6] rotavirus strain isolated from an infant in Belgium

Interspecies transmissions of group A rotavirus (RVA) strains among animals and humans are thought to take place frequently. During a RVA surveillance study in Belgium we isolated an unusual G9P6] RVA strain, RVA/human-wt/BEL/BE2001/2009/G9P6], from a 1month old boy, which did not cluster with other G9 or P6] strains isolated in Belgium. In this study we sequenced and characterized the complete genome of this unusual G9P6] strain BE2001. Phylogenetic analyses of all 11 genes revealed a unique genotype constellation: G9-P6]-I5-R1-C1-M1-A8-N1-T7-E1-H1. The VP6 and NSP1 genotypes I5 and A8 are genotypes commonly found in porcine RVA strains, while the VP7 and VP4 genes clustered only distantly to human lineages of G9 and P6], respectively. The VP1, VP2, VP3, NSP2, NSP4 and NSP5 genes all belonged to Wa-like genotypes, but clustered more closely to porcine strains than to human strains. NSP3 belonged to the rare T7 genotype. Thus far, T7 genotypes have only been detected in one porcine-like human strain (RVA/human-tc/CHN/R479/2004/G4P6]), one bovine-like human strain (RVA/human-xx/IND/mani-265/2007/G10P6]) and one bovine RVA strain (RVA/cow-tc/GBR/UK/1973/G6P75]). Sequence analysis of the BE2001 NSP5 gene segment revealed a 300 nucleotide duplication in the 3' end non-coding region. BE2001 is most likely a direct interspecies transmission between a pig and a human. Inquiry with the patient's physician revealed that the father of the patient had been working on a pig farm in the week the patient became ill, providing a plausible route of transmission.