The impact of seasonal climate on new case detection rate of leprosy in Brazil (2008–2012)

Objective: To examine the impact of climatic seasonality in the new case detection rate of leprosy in Brazil according to geographical regions, climates and biomes over a 5-year period, 2008–2012. Methods: We conducted an ecological study of the monthly new case detection rate of leprosy in spatial aggregation of Brazilian geographical regions, climates and biomes, applying a linear regression models with Poisson function to estimate seasonal rates using January as the reference month. Results: Monthly seasonal patterns of leprosy detection rates were recorded between different geographic regions, biomes and climates, with a predominance of increases in the autumn, in the months of March and May, and in winter in the month of August. Conclusions: The detection rate of leprosy in Brazil has a seasonal pattern with specific variations between geographical regions, climates, and biomes. The highest peaks in the detection rates were observed in May (autumn) and in August (winter). In addition to the supply and accessibility of healthcare services, these patterns, may also be related to cultural and environmental factors.