A Case Control Study to Explore the Risk Factors for Acquisition of Leptospirosis in Surat City, After Flood

Background: Between August and November 2006, a population-based case control study was conducted to identify the probable risk factors for leptospirosis during flooding in Surat city. Materials and Methods: Sixty-two laboratory confirmed cases out of 129 suspected cases, and 253 age and sex matched fever and healthy controls were interviewed with the help of predesigned questionnaire. The association of risk factors with acquiring leptospirosis was assessed by adjusted OR with the help of logistic regression model to control confounders. Results: By univariate analysis, factors identified were, walking barefoot (OR = 10.34, 95% CI 5.09-21.31, P < 0.001), contact of injured part with flood water (OR = 9.65, 95% CI 4.81-19.61, P < 0.001), use of flood water for cooking (OR = 5.94, 95% CI 2.5-14.06, P < 0.001), for washing (OR = 4.21, 95% CI 1.74-10.17, P < 0.001), swimming in flood water (OR = 3.66, 95% CI 1.97-6.83, P < 0.001) and bathing (OR = 2.69, 95% CI 1.02-7.05, P < 0.001), trash within 500 m (OR = 4.31, 95% CI 1.41-14.76, P < 0.05) and rats in surroundings (OR = 11.05, 95% CI 3.18-45.9, P < 0.001). By multivariate analysis, four factors identified were, contact of injured part with flood water (Adjusted OR = 6.69, 95% CI 3.05-14.64, P < 0.001), walking barefoot (Adjusted OR = 4.95, 95% CI 2.22-11.06, P < 0.001), constant presence of rats in household (Adjusted OR = 4.95, 95% CI 1.53-16.05, p < 0.05) and spending more than four days in cleaning (Adjusted OR = 2.64, 95% CI 1.18-5.89, P < 0.05). Conclusions :Prompt and vigilant fever surveillance activities in pre-monsoon preparedness plan, intensive IEC messages, rodent control programs and improvement of environmental sanitary conditions may help to greatly reduce the incidence of leptospirosis