Diagnosis of leptospirosis and comparison of ELISA and MAT techniques.

Leptospirosis is perhaps the most common, most wide spread yet under diagnosed zoonosis in the world, Inada et al identified the causal agent in Japan in 1916. Microscopic agglutination test (MAT) developed initially by Martin and Pettit (1918) is the reference method that was successively done after ELISA test to evaluate and compare and make a reliable diagnosis. Blood samples were collected from August 2004 to September 2004 from hospitalized patients of South Gujarat region who were clinically suspected cases of leptospirosis according to WHO case definition. In our setup we separated the sera and carried out ELISA for detection of IgM antibodies and rest of the sera were stored at -20 degrees C. As we do not have the facility for performing MAT test in our centre, we personally carried these sera to Chennai for performing the MAT and identified the serovars prevalent in South Gujarat region. Out of 30 samples tested 16 samples (53.3%) were positive by ELISA and 12 samples (40%) were negative by ELISA. By MAT, 17 samples (56.67%) were found positive and 13 samples (43.33%) were negative. 2 samples were borderline by ELISA and these turned out to be negative by MAT. Cosidering MATas the gold standard the sensitivity of IgM ELISA in this study was 88% and specificity 90.90%. We concluded that IgM ELISA is rapid test and its results are quite similar to MAT. The most common serovars isolated and identified are L. hebdomadis, L. pyrogenes, L. autumnalis and L. grippotyphosa in this part of the country.