Abstract

Leptospirosis remains a significant public health concern in the Philippines, particularly in urban tropical settings where environmental and climatic conditions favor disease transmission. This study examined temporal trends and factors associated with human leptospirosis in Davao City, Philippines, using surveillance data from 2015 to 2025. A retrospective observational study was conducted using 1104 surveillance records obtained from the Davao City Health Office–City Epidemiological Surveillance Unit. Annual incidence and mortality rates were calculated per 100,000 population; temporal trends were assessed using Mann–Kendall tests; and associations with demographic, seasonal, geographic, and environmental factors were evaluated using Poisson and negative binomial regression models, as appropriate, based on model diagnostics and comparative fit. Increasing incidence trends were observed across several strata, whereas increasing mortality trends were identified in selected demographic and environmental categories. In the incidence analysis, a higher disease burden was associated with age ≥ 15 years (aIRR = 14.75, 95% CI: 10.77–20.21), male sex (aIRR = 4.78, 95% CI: 3.74–6.11), high population density (aIRR = 4.19, 95% CI: 2.75–6.38), and the wet season (aIRR = 1.30, 95% CI: 1.04–1.61). Mortality was also strongly associated with age ≥ 15 years (aIRR = 36.75, 95% CI: 13.61–99.22) and male (aIRR = 8.50, 95% CI: 4.73–15.27). These findings provide a long-term surveillance-based assessment of leptospirosis in Davao City and identify demographic and environmental patterns relevant to targeted surveillance, seasonal preparedness, and locally adapted prevention strategies for leptospirosis.

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