Climate change and dengue: what the models show
A look at how temperature and rainfall projections are reshaping where vector-borne disease risk will fall.
Vector-borne disease risk is unusually sensitive to climate because the mosquito, the pathogen, and the biting rate all respond to temperature. Modeling studies converge on a consistent picture: the map of risk is shifting, not simply growing.
Why temperature matters so much
- Extrinsic incubation period. Warmer temperatures let the virus replicate faster inside the mosquito, so a higher fraction of mosquitoes become infectious within their lifespan.
- Biting frequency rises with temperature up to a thermal optimum (around 29 °C for Aedes aegypti–borne dengue).
- The relationship is hump-shaped: beyond the optimum, transmission falls. Some currently hot regions may become less suitable while cooler regions become more suitable.
What the projections suggest
- A net expansion of the population at risk for dengue and an extension of transmission seasons in temperate zones.
- Altitude shifts: highland areas previously protected by cool temperatures (parts of the East African and Andean highlands) face rising suitability.
- For malaria, the picture is more mixed — some regions gain suitability, others lose it as they exceed thermal limits or dry out.
How to read this as a traveler
Models describe suitability, not certainty. Local control, urbanization, and surveillance heavily modify real risk. The practical takeaway: check current, season-specific guidance for your destination rather than relying on historical "this region is/ isn't risky" assumptions.
Bottom line: climate is widening and shifting the risk map. Static mental models age badly — current data beats reputation.