title: Evaluation of an antigen capture ELISA based on recombinant mexico virus capsid protein.
abstract: BACKGROUND
  The diagnosis of gastrointestinal infections caused by small round structured viruses (SRSV) has relied upon electron microscopy and antigen/antibody assays based on Norwalk virus. We investigated cases of gastroenteritis associated with SRSVs employing a new sandwich enzyme-linked immunosorbent assay (ELISA) using hyperimmune animal anti-sera against recombinant Mexico virus capsid protein (rMXV).
  
  
  METHODS
  One hundred and thirty-five specimens from 86 episodes of gastroenteritis associated with SRSVs, collected in the UK between October 1993 and September 1994, were tested in the rMXV assay.
  
  
  RESULTS
  Forty-seven (35%) specimens from 35 of 86 (41%) episodes were positive in the rMXV ELISA and these could further be divided into high and low reactors. Sequencing of a 266-base region of the RNA polymerase gene revealed that strains highly reactive in the rMXV assay demonstrated a high degree of similarity to MXV (97-99% at the nucleotide level), whereas low-reactive strains consist of Mexico-like strains and a heterogeneous group of viruses exhibiting 70-75% similarity to MXV.
  
  
  CONCLUSIONS
  Our results indicate that the rMXV ELISA is predominantly a type specific assay, although some cross reactivity with other genogroup 2 SRSVs was observed. MXV was responsible for 26% of SRSV-associated gastrointestinal infections investigated in the UK during one year's surveillance.
authors.affiliation: Enteric and Respiratory Virus Laboratory, Central Public Health Laboratory, 61 Colindale Ave., London, NW9 5HT, UK.
authors.forename: A D
authors.initials: AD
authors.lastname: Hale
authors.forename: D
authors.initials: D
authors.lastname: Lewis
authors.forename: J
authors.initials: J
authors.lastname: Green
authors.forename: X
authors.initials: X
authors.lastname: Jiang
authors.forename: D W
authors.initials: DW
authors.lastname: Brown