Leptospirosis incidence in a state capital in the Western Brazilian Amazon and its relationship with climate and environmental variability, 2008-2013

Abstract

Objective: to analyze association between environmental variables and leptospirosis incidence in the municipality of Rio Branco, Acre, Brazil, 2008-2013. Methods: this was an ecological study of association between monthly average environmental variables and monthly leptospirosis incidence, according to generalized autoregressive score models and moving averages. Results: increases in the monthly average levels of the River Acre and days of precipitation per month were associated with a 7% increase (incidence rate ratio [RR] 1.07 - 95%CI 1.02;1.14) and a 4% increase (RR 1.04 - 95%CI 1,00;1,07) in the monthly incidence of leptospirosis, respectively; in 2013 leptospirosis incidence in the municipality was 8 times higher than in 2008 (RR 8.00 - 95%CI 4.07;15.71). Conclusion: this study showed a strong increase in leptospirosis incidence, over the years studied, and positive associations with environmental variables.