title: Evaluation of an in-house ELISA using the intermediate species Leptospira fainei for diagnosis of leptospirosis.
abstract: Leptospirosis is recognized as an emerging zoonotic disease generally affecting urban slums in developing countries and tropical regions. A combination of non-specific symptoms, low awareness among the medical community and a lack of readily available diagnostic tests have made leptospirosis an underdiagnosed disease. In this study, we tested an in-house ELISA with formalin-treated and boiled bacteria from the intermediate species Leptospira fainei as an antigen to detect Leptospira-specific IgM antibodies. A total of 819 serum samples, tested by a microscopic agglutination test (MAT) as a reference test, were used to evaluate the ELISA. Compared with positive and negative sera, the ELISA showed 94 % sensitivity and 99 % specificity. Positive and negative likelihood ratios were 94 and 0.06, respectively. No cross-reactivity was observed in sera from subjects with dengue and syphilis infections. The kappa value was 0.92 (95 % confidence interval 0.88-0.96), which indicated excellent agreement between the MAT and ELISA. The overall performance of this in-house ELISA suggests applicability as a rapid screening test for the diagnosis of leptospirosis in resource-limited settings and in hospitals and laboratories where a MAT is not available.
authors.affiliation: Institut Pasteur, Biology of Spirochetes Unit, National Reference Center and WHO Collaborating Center for Leptospirosis, Paris, France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Bourhy
authors.affiliation: Institut Pasteur, Unité de Recherche et d'Expertise Epidémiologie des Maladies Emergentes, Paris, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Vray
authors.affiliation: Institut Pasteur, Biology of Spirochetes Unit, National Reference Center and WHO Collaborating Center for Leptospirosis, Paris, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Picardeau
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000372:Agglutination Tests; D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D003906:Developing Countries; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D007919:Leptospira / Q000145:classification / Q000276:immunology*; D007922:Leptospirosis / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M; D011933:Reagent Kits, Diagnostic