Leptospirosis incidence and mortality: a spatio-temporal analysis, Ceará, 2007-2023

To analyze the spatio-temporal pattern of leptospirosis incidence and mortality in Ceará between 2007 and 2023.

This was a descriptive observational study with temporal (joinpoint regression), spatial (Bayesian smoothing and Getis-Ord Gi*), and spatio-temporal (scan) analyses to identify risk areas, based on secondary data from the Department of Informatics of the Brazilian National Health System. The study assessed the incidence and mortality rates of leptospirosis in Ceará between 2007 and 2023.

A total of 1,319 leptospirosis cases were recorded, mostly among men (83.9%, n=1,107), young adults aged 15-39 years, and Brown (Brazilian mixed race) people (78.5%, n=1,035). Temporal analysis of incidence revealed three periods of interest: 2007-2009, 2009-2013, and 2013-2023, with respective annual percent changes (APC) and 95% confidence intervals (95%CI): (i) 91.4% (95%CI 24.9; 203.8; p-value 0.002); (ii) -38.4% (95%CI -54.5; -26.8; p-value 0.002); and (iii) 9.4% (95%CI 2.8; 21.1; p-value 0.007). Mortality also showed three distinct periods: a decrease between 2007 and 2014 (APC -13.7%; 95%CI -38.5; -2.8; p-value 0.020), an increase between 2014 and 2019 (APC 27.6%; 95%CI 8.5; 88.8; p-value 0.010), and another decline between 2019 and 2023 (APC -20.6%; 95%CI -58.8; -6.4; p-value 0.010). Hotspots of incidence were identified in Fortaleza, Várzea Alegre, and Pacoti.

Leptospirosis in Ceará is associated with heavy rainfall and precarious socio-environmental conditions. Integrated prevention measures, such as improved sanitation and rodent control, are crucial for reducing the disease burden in the state.