Monsoon-driven dynamics of infectious diseases: Climatic determinants, outbreak patterns, and public health implications

• Monsoon triggers surges in waterborne, vector, and airborne infections. • Floods enable cholera, leptospirosis, and hepatitis E outbreaks. • Dengue and malaria intensify due to post-rainfall mosquito breeding. • Climate change shifts monsoon patterns, altering epidemic timing. • Respiratory and fungal infections rise due to flood-related exposures. Monsoon rainfall drives substantial shifts in infectious disease transmission through changes in hydrology, vector ecology, and human-environment interactions. Elevated humidity, flooding, and water stagnation create conditions that favor the propagation of pathogens, such as Vibrio cholerae , Leptospira interrogans , and arboviruses transmitted by Aedes and Culex mosquitoes. Respiratory viruses and invasive fungal infections also increase owing to overcrowding and compromised air quality during monsoon-induced displacement. Climatic thresholds, including sea surface temperature, relative humidity, and rainfall anomalies, correlate strongly with epidemic peaks. Intensifying monsoon variability due to climate change alters the geography, seasonality, and burden of these diseases, challenging existing public health models and demanding integrated climate-pathogen surveillance systems.