Seroprevalence and Risk Factors Associated with Leptospirosis in High-Risk Occupational Groups in the State of Gujarat as Determined by IgM ELISA and MAT Test: A Cross-Sectional Study.

Background: Leptospirosis is a reemerging zoonosis affecting humans and animals worldwide in tropical and subtropical countries. The study was conducted to estimate the seroprevalence of leptospirosis in high-risk occupational groups (cattle farm workers, poultry farm workers, and slaughterhouse workers) in the state of Gujarat and to determine related risk factors for leptospirosis.

Methods: Using an interview-guided questionnaire, a cross-sectional study was conducted involving 123 people in high-risk occupational groups (namely, cattle farm workers, poultry farm workers, and slaughterhouse workers) from five districts of the state of Gujarat, India. The participants' serum samples were screened for antileptospiral antibodies by using Immunoglobulin G (IgG) and Immunoglobulin M (IgM) enzyme-linked immunosorbent assays (ELISAs) followed by a microscopic agglutination test (MAT). The Chi-square (χ²) test and odds ratio were calculated using IBM SPSS Statistics for Windows, version 22 (IBM Corp., Armonk, N.Y., USA) to ascertain the associated risk factors.

Results: Regarding demographic information, this study included 104 men and 19 women in high-risk occupational groups. The overall seroprevalence of antileptospiral antibodies in these high-risk workers was 46.3%. The seroprevalence was the highest among poultry farm workers (56.6%), followed by cattle farm workers (54.5%) and slaughterhouse workers (25.6%). The MAT in combination with IgM is adequate for the serological diagnosis of leptospirosis, but we have also employed IgG ELISA to understand the chronic infection in these high-risk occupational groups as exposure was both past and present. Tests were conducted for antibodies against various Leptospira serovars in the major serogroups; frequent serovars included Hurstbridge, Panama, Javanica, Tarassovi, Copenhageni, Pomona, and Weaveri, among others. The significant (P < 0.05) risk factors associated with leptospirosis in these high-risk occupations reported to be living in field areas, the presence of livestock in the neighborhood, working in slaughterhouses, drinking water from natural water resources, contact with animals such as dogs or livestock, and wounds during occupational practice.

Conclusion: Considering the high seroprevalence of leptospirosis, high-risk occupational groups should be regularly screened for potential development of the fatal disease. Hurstbridge was found to be the most prevalent serovar in the studied population, followed by Panama, Javanica, and Tarassovi.