title: Evaluation of a commercial ELISA for detecting Norwalk-like virus antigen in faeces.
abstract: A commercially available enzyme immunoassay, the IDEIA Norwalk-like virus (NLV) enzyme linked immunosorbent assay (ELISA; Dako Cytomation, Ely, UK) for detecting NLV antigen in faecal samples and determining the NLV genogroup was evaluated. The performance of the ELISA was compared with that of electron microscopy and the reverse transcription polymerase chain reaction by testing a panel of faecal samples collected from patients involved in outbreaks of gastroenteritis. When compared with reverse transcription-polymerase chain reaction (RT-PCR), the ELISA had a sensitivity and specificity of 55.5 and 98.3%, respectively. This compares with a sensitivity and specificity for EM of 23.9 and 99.2%, respectively. The sensitivity and specificity of the ELISA for determining the aetiology of a Norwalk virus-like outbreak, based on two or more positive samples within an outbreak, were 52.2 and 100% when two samples were collected from an outbreak and 71.4 and 100% when six or more samples were collected. The ELISA correctly identified the NLV genogroups of viruses previously characterised by partial DNA sequencing. The ELISA is a suitable alternative to the preliminary screening by EM for investigating outbreaks of gastroenteritis. Outbreaks, negative by ELISA should be examined by RT-PCR in order to detect strains non-reactive in the assay and virus strains from representative ELISA positive outbreaks should be characterised fully to allow the genetic diversity of NLVs co-circulating in the population to be described.
authors.affiliation: Enteric Virus Unit, Enteric, Respiratory and Neurological Virus Laboratory, Central Public Health Laboratory, 61 Colindale Ave., London NW9 5HT, UK.
authors.forename: A F
authors.initials: AF
authors.lastname: Richards
authors.forename: B
authors.initials: B
authors.lastname: Lopman
authors.forename: A
authors.initials: A
authors.lastname: Gunn
authors.forename: A
authors.initials: A
authors.lastname: Curry
authors.forename: D
authors.initials: D
authors.lastname: Ellis
authors.forename: H
authors.initials: H
authors.lastname: Cotterill
authors.forename: S
authors.initials: S
authors.lastname: Ratcliffe
authors.forename: M
authors.initials: M
authors.lastname: Jenkins
authors.forename: H
authors.initials: H
authors.lastname: Appleton
authors.forename: C I
authors.initials: CI
authors.lastname: Gallimore
authors.forename: J J
authors.initials: JJ
authors.lastname: Gray
authors.forename: D W G
authors.initials: DW
authors.lastname: Brown
mesh_terms: D000956:Antigens, Viral / Q000032:analysis*; D017250:Caliciviridae Infections / Q000453:epidemiology / Q000821:virology*; D036022:Capsid Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000821:virology*; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology*; D005838:Genotype; D006801:Humans; D008854:Microscopy, Electron; D029322:Norovirus / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D012367:RNA, Viral / Q000235:genetics; D011933:Reagent Kits, Diagnostic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
chemical_list: D000956:Antigens, Viral; D036022:Capsid Proteins; D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic