Molecular epidemiology of outbreaks of gastroenteritis associated with small round-structured viruses in East Anglia, United Kingdom, during the 1996-1997 season

During the winter season from November 1996 to May 1997, 550 fecal specimen s were submitted from 94 outbreaks of gastroenteritis occurring in East Ang lia, United Kingdom. These specimens were tested for the presence of small round-structured viruses (SRSVs) by electron microscopy, reverse transcript ase PCR, or both methods. SRSVs were shown to be associated with 64 of 94 ( 68%) of these outbreaks, of which 16 (25%) outbreaks occurred at a single l ocation (Southeud) within the region. Twenty-four specimens from 13 of the 16 SRSV-positive outbreaks occurring in Southend were available for genomic analysis, in which divergence within the RNA polymerase region of the SRSV genome was investigated. A further 27 specimens from 17 other SRSV-associa ted outbreaks, occurring at different locations within East Anglia but at t he same time as those at Southend, were also studied. Fifty of the total of 51 (98%) specimens studied were shown to belong to genogroup II, and withi n this genogroup, 49 of 50 (98%) specimens were shown to be Grimsby-like vi ruses, with only one Mexico-like strain. Furthermore, phylogenetic analysis of the Grimsby-like viruses indicated clusterings according to the geograp hical location of the outbreak. One specimen contained a virus belonging to genogroup I, and this had the greatest sequence identity (83%) with Southa mpton virus.