In-house ELISA screening using a locally-isolated Leptospirain Malaysia: determination of its cut-off points

Abstract

BackgroundLeptospirosis is a zoonotic disease caused by Leptospira species and is distributed globally. Microscopic agglutination test (MAT) is the serological ‘gold standard’ for diagnosis of leptospirosis but it is time-consuming and labour-intensive. An alternative serological method that is rapid, sensitive and specific is important for early treatment to reduce morbidity and mortality. The use of local Leptospira isolation may improve the sensitivity and specificity of the test because it may varies from one geographical region to another region. The objective of this study was to determine the sensitivity, specificity and cut-off points for an in-house Immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) using a locally isolated Leptospiral strain IMR/175 as the antigen for the detection of anti-Leptospiral IgM.MethodsSerum samples from 270 patients with clinical symptoms of leptospirosis were subjected to the in-house IgM ELISA, MAT and Leptospirosis rapid test. The optimal cut-off values for positivity and negativity of the IgM ELISA were determined by Receiver Operating Characteristic curves and mean ± 2 standard deviation (SD) analyses of the ELISA values.ResultsThe area under the curve (AUC) which indicates the diagnostic performance of the in-house IgM ELISA was 0.953 (95% Confidence Interval, CI: 0.928, 0.978). The sensitivity and specificity of 90.38% and 87.72% respectively were obtained with the cut-off point of 0.55. A higher sensitivity (96.15%) was obtained when the cut-off point was set at 0.45.ConclusionsThe in-house IgM ELISA assay using local Leptospira isolation was shown to be sensitive and may be suitable to use for the serological diagnosis of leptospirosis for our local hospital setting.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0563-7) contains supplementary material, which is available to authorized users.

Biogeography of Leptospira in wild animal communities inhabiting the insular ecosystem of the western Indian Ocean islands and neighboring Africa

“…Indeed, a previous study suggested a negative relationship between mammalian diversity and human incidence of leptospirosis in island ecosystems, which may be explained by both bioregulation and dilution effects 44 . To answer these questions, it will be necessary to improve current techniques for culturing Leptospira from field samples and to develop tests for Leptospira infection capable of detecting local host-associated Leptospira lineages 45 . Such investigations would allow for a greater understanding at the global level of the role of different host/reservoir species in human leptospirosis and the design of improved preventive measures.…”

Application of Multilocus Sequence Typing for the Characterization of Leptospira Strains in Malaysia

“…The isolates obtained from three cattle, two dogs, and one environmental sample were closely related to L. kmetyi serovar Malaysia (Group 2) and L. yasudae (Group 3) ( Figure 2 ), with a mean genetic distance within group of 0.001 and 0.002, respectively ( Table 3 ). These animals could become infected with Leptospira because of constant exposure to contaminated soil, as L. kmetyi was mostly isolated from environmental samples [ 44 , 45 , 46 ]. In addition, a novel species, L. yasudae was also isolated from the soil of an ex-situ wild animal conservation area in Malaysia recently [ 47 ].…”

Detection of Anti-LipL32 Antibodies in Serum Samples from Horses with Chronic Intraocular Infection with Leptospira spp.

“…Various ELISA tests, among others, have been described as serological tests complementary to MAT [70,[74][75][76]94,99]. Most commercially available ELISA tests detect immunoglobulin class M antibodies, which are critical for early diagnosis of acute infection and are often detectable before MAT becomes positive [75,76,78,98,100,101].…”