Early laboratory diagnosis of leptospirosis is important to provide appropriate treatment of patients and to take rapid measures in case of an outbreak. Unfortunately, few tests possess both high sensitivity and specificity; this is particularly true during the acute phase of the disease. We developed 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. Compared with positive and negative sera, the ELISA showed 94% sensitivity and 99% specificity. We also evaluated a prototype point of care strip test by using the same antigen for the serological diagnosis of leptospirosis in New Caledonia, mainland France, and the French West Indies. The sensitivity was 89.8% and the specificity 93.7%.
Although PCR is increasingly presented as the method of choice for the diagnostic of acute leptospirosis, there is little information on the comparability of these PCR-based methods. We compared the sensitivity and specificity of previously described PCR assays with both SYBR green and TaqMan chemistries, as well as the PCR performance of whole-blood, plasma, and serum specimens after DNA extraction with two commercialized kits.