Climate Change and Dengue Dynamics in South Indian States: A Decade of Evidence (2013–2022)

Climate change significantly influences vector-borne disease transmission patterns. Understanding the relationship between climatic variables and dengue transmission is crucial for public health planning in tropical regions. To examine the association between climatic variables (rainfall, humidity, temperature) and dengue incidence and mortality in six south Indian states from 2013 to 2022. We conducted a longitudinal ecological study using dengue surveillance data from the National vector-borne disease control program and climatic data from NASA Power Access and CHRS databases. Time series analysis, cross-correlation analysis with lag effects, and negative binomial regression models were employed to examine relationships between climate variables and dengue outcomes, controlling for temporal trends and seasonal patterns. During 2013-2022, 892,456 dengue cases and 2,847 deaths were reported across six states. Strong positive correlations were observed between rainfall and humidity (r=0.90-0.98, p<0.001). Rainfall was most strongly associated with dengue cases at 4–6-week lags (r=0.35- 0.68). Temperature demonstrated non-linear relationships with peak transmission at 26-30℃. Regression analysis revealed that a 100mm increase in monthly rainfall was associated with a 15-25% increase in dengue cases. Maharashtra, Telangana, and Andhra Pradesh reported the highest case burdens. Climatic variables, particularly rainfall and humidity with temporal lags, significantly influenced dengue transmission in South India. These findings support the development of climate-based early warning systems for dengue outbreak prediction and control.