As many as 360 patients admitted with suspected leptospirosis were studied by clinical examination, baseline ophthalmic survey, laboratory investigations and Leptospiraserology (Microagglutination test - MAT; and IgM and IgG using ELISA) during the epidemic. Of the 282 seropositive and antibiotic-treated cases, 174 patientswho completed 30 months of regular follow-up were analyzed. A cross-sectional serosurveillance also was performed among 50 sewageworkers to determine the baseline MAT titer. Statistical