International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases | 2021
Development of an In-House ELISA as an alternative method for the serodiagnosis of leptospirosis.
Abstract
BACKGROUND\nLeptospirosis is most often clinically diagnosed and a laboratory test with high diagnostic accuracies is required.\n\n\nMETHODOLOGY\nIgM and IgG-ELISAs using Leptospira antigens were established and evaluated in relation to the Microscopic Agglutination Test (MAT). Antigen preparation consisted either saprophytic Leptospira biflexa to detect genus specific antibodies (genus-specific ELISA) or a pool of five most prevalent Leptospira interrogans serovars in Sri Lanka to detect serovar specific antibodies (serovar-specific ELISA). IgM and IgG immune responses in severe and mild leptospirosis patients (n\u2009=\u2009100 in each group) were studied.\n\n\nRESULTS\nELISAs showed high repeatability and reproducibility. Serovar-specific IgM-ELISA showed sensitivity of 80.2% and specificity of 89%; genus-specific IgM-ELISA showed sensitivity of 83.3% and specificity of 91%. Serovar and genus-specific IgG-ELISA showed sensitivities of 73.3% and 81.7%, and specificities of 83.33%. Commercial IgM-ELISA showed sensitivity and specificity of 79.2% and 93% respectively. Commercial IgG-ELISA showed sensitivity, specificity of 50% and 96.7% respectively. IgM levels observed in mild and severe leptospirosis (ML & SL) patients were significantly higher than healthy control (HC) group, having absorbance mean of 0.770, 0.778 and 0.163 respectively. In contrast, SL patients had significantly higher mean anti-leptospiral IgG levels compared to both ML and HC groups (0.643, 0.358 and 0.116 respectively; ANOVA, P\u2009<\u2009 0.001). Presence of anti-leptospiral IgG above OD 0.643 optical density (OD) at 1:100 could predict high risk of severe disease.\n\n\nCONCLUSION\nSerovar-specific In-House ELISAs could be used for the laboratory diagnosis of leptospirosis in endemic settings. Observed high levels of anti-leptospiral IgG suggest its value as a predictor for disease severity.