The incidence of hospitalized leptospirosis patients was positively associated with increased precipitation in Salvador, Brazil. However, Leptospira infection risk among a cohort of city residents was inversely associated with rainfall. These findings indicate that, although heavy rainfall may increase severe illness, Leptospira exposures can occur year-round.
Keywords: Brazil; Leptospira; bacteria; epidemiology; leptospirosis; public health; rainfall; seasonal infection; slum health; temporal dynamics; urban epidemiology; waterborne infections; zoonoses.