Characterisation of rotavirus G9 strains isolated in the UK between 1995 and 1998

G9P[6] and G9P[8] rotavirus strains were identified during 1995/96 through the molecular epidemiological surveillance of rotavirus strains circulating in the UK between 1995 and 1998. An increase in the incidence and spread o f sporadic infections with rotavirus genotype G9P[8] across the UK was dete cted in the two following seasons. Partial sequencing of the VP7 gene showe d that all the UK strains shared a high degree of homology and were related very closely to G9 strains from the US and from symptomatic infections in India (greater than or equal to 96% homology). The UK strains were related more distantly to the apathogenic Indian strain 116E (85-87.8% homology). P hylogenetic analysis revealed clustering of the UK strains into 3 different lineages (I to III) and into two sub-lineages within lineage I. There were correlations between VP7 sequence clustering, the P type and the geographi cal origin of the G9 strains. Partial sequencing of the VP4 gene showed hig h degree of homology (>98%) among all the P[6] strains, and the sequences o btained from the P[8] strains clustered into 2 of the 3 global lineages des cribed for P[8] strains associated with other G types. These data suggest t hat G9 strains may be a recent importation into the UK, and that G9P[8] str ains may have emerged through reassortment in humans between G9P[6] strains introduced recently and the more prevalent cocirculating Gl, G3 and G4 str ains that normally carry VP4 genes of P[8] type. J. Med. Virol. 61:510-517, 2000. (C) 2000 Wiley-Liss, Inc.