Serodiagnosis of bovine leptospirosis by IgG-Enzyme-Linked Immunosorbent Assay and Latex Agglutination Test T. M. A. Senthilkumar & M. Subathra & P. Ramadass & V. Ramaswamy Accepted: 29 July 2009 / Published online: 14 August 2009 # Springer Science + Business Media B.V. 2009 Abstract The efficacy of a recombinant leptospiral outer membrane protein LipL41 as an antigen for conducting IgG-Enzyme linked immunosorbent assay (ELISA) and latex agglutination test (LAT) for serodiagnosis of bovine leptospirosis was evaluated. The recombinant LipL41 antigen developed and used for detecting the antibodies was specific in detection of the pathogenic serovars of Leptospira, as the expression of the LipL41 antigen is restricted only to pathogenic leptospires. A total of 430 bovine serum samples were subjected to IgG-ELISA and LAT, and the sensitivity and specificity were assessed in comparison with microscopic agglutination test (MAT). The sensitivity and specificity of IgG- ELISA and LAT were 86.84% and 93.16%, and 95.42% and 98.33% respectively. Both the tests are found to be sensitive, specific and concurred with the standard MAT. The study concluded that the rLipL41 protein could be used as a potential diagnostic antigen in different assay formats for bovine leptospirosis. Keywords Cattle . IgG-ELISA . Latex agglutination test . Serodiagnosis . rLipL41 Introduction Leptospirosis is one of the most important zoonoses with worldwide distribution. In domestic animals, it is an important cause of abortion, stillbirth, infertility, decreased milk production and death (Haake et al. 1998; Bharti et al. 2003). The gold standard serologic test, the microscopic agglutination test (MAT), is inadequate for rapid case identification since it can only be performed in a few laboratories and requires paired, acute and convalescent serum samples (Cumberland et al. 1999; Faine et al. 1999). The other serological methods like Enzyme-linked immunosorbent assay (ELISA), dipstick ELISA and latex agglutination test (LAT) have already been developed based on whole-cell leptospiral antigen preparations to screen for leptospiral infection (Yersin et al., 1999; Ramadass et al. 1999). The whole-cell antigen preparations possess broadly reactive immunodominant epitopes present in both pathogenic and non-pathogenic leptospires as well as a diverse group of non-leptospiral species (Matsuo et al. 2000). There is an urgent need for development of new serodiagnostic strategies that could be used in routine diagnostic laboratory to detect antibodies against leptospires. Recently, recombinant antigen Trop Anim Health Prod (2010) 42:217–222 DOI 10.1007/s11250-009-9409-5 T. M. A. Senthilkumar (*) : M. Subathra : P. Ramadass Department of Animal Biotechnology, Madras Veterinary College, Chennai 600 007, India e-mail: tmaskumar@yahoo.com V. Ramaswamy Department of Veterinary Microbiology, Madras Veterinary College, Chennai 600 007, India