Malaria transmission potential could be reduced with current and future climate change

Area of Science:

• Environmental Science
• Vector-borne Diseases
• Climate Change Impact

Background:

• Climate change is projected to alter malaria distribution, with focus on cooler regions.
• The impact of warming on malaria transmission in already warm, endemic areas is less understood.
• Investigating temperature effects on malaria vectors is crucial for accurate risk assessment.

Purpose of the Study:

• To assess how increased temperatures and diurnal temperature ranges affect malaria transmission by key African and Asian mosquito vectors.
• To quantify the impact of specific temperature increases and diurnal temperature variations on Plasmodium falciparum transmission.
• To evaluate the combined effects on vector species Anopheles gambiae and Anopheles stephensi.

Main Methods:

• Simulated increased temperatures (27°C to 30°C and 33°C) and diurnal temperature ranges (DTR: ±0°C, ±3°C, ±4.5°C).
• Assessed effects on parasite prevalence, parasite intensity, and mosquito mortality for Anopheles gambiae and Anopheles stephensi.
• Calculated changes in overall vectorial capacity under different temperature scenarios.

Main Results:

• Increased temperature and DTR significantly decreased the vectorial capacity of both mosquito species.
• A 3°C rise from 27°C reduced vectorial capacity by 51-89%, depending on species and DTR.
• Higher temperatures (33°C) further reduced transmission for An. stephensi and blocked it in An. gambiae.

Conclusions:

• Even small temperature shifts can substantially alter malaria transmission dynamics.
• Increased diurnal temperature ranges can significantly reduce malaria transmission potential.
• Contrary to some expectations, projected warming may reduce malaria transmission in current high-transmission settings.