Climate change could push mosquito-borne diseases into new parts of Africa

Climate change could push mosquito-borne diseases into new parts of Africa

7 October 2026 - Wits University

Warning comes as Southern Africa is faced with a particularly dangerous combination of a strong El Niño and long-term global warming.

Climate change is expanding the range of disease-carrying mosquitoes and could expose more people in African cities to malaria, dengue, yellow fever, chikungunya and Zika, Wits public health expert Professor Helen Rees has warned.

Speaking at the African Academy of Sciences Presidential Lecture Series on climate change and health, Rees said warmer conditions are changing where mosquitoes can survive, how long transmission seasons last and which populations are at risk.

"What we're seeing is expanded mosquito ranges both to higher latitudes and altitudes," she said. "There's lengthening of transmission seasons in some of the regions."

Rees highlighted the spread of Anopheles stephensi, a malaria-carrying mosquito originally from South Asia and the Arabian Peninsula, which is now expanding across the Horn of Africa and into African cities.

"It thrives in urban environments and it breeds in water storage containers and other man-made habitats," she said. The mosquito can transmit both major forms of malaria, while growing insecticide resistance and difficulties with some rapid diagnostic tests add to the threat.

Rees also warned that Aedes mosquitoes, which spread dengue, yellow fever, chikungunya and Zika are likely to expand their distribution as temperatures rise.

"The spread that we could potentially see of these infectious diseases could be very, very significant in the African region," Rees said.

Her warning came as Wits climate scientist and Director of the Wits Global Change Institute, Professor François Engelbrecht, said Southern Africa faced a particularly dangerous combination of a strong El Niño and long-term global warming.

Southern Africa is likely to experience below-normal rainfall and drought, while East Africa faced a greater chance of heavy rainfall and flooding. Engelbrecht said the Mozambique Channel is now warm enough to sustain an extremely powerful tropical cyclone, with evidence pointing to the possibility of a Category 5 landfall in Mozambique within the next decade.

The coming summer could bring unprecedented heat to Southern Africa. El Niño is also giving the continent a glimpse of what a warmer future may look like. Evidence suggests stronger El Niño events could occur more frequently, meaning Africa will need to prepare for repeated drought, heat and flood risks.

Climate science, however, gives governments an opportunity to act before disaster strikes.

"We have a chance to prepare because the climate models help us to anticipate what the main risks are," Engelbrecht said, adding that early-warning systems, adaptation planning and protecting vulnerable communities will become increasingly important.

WHO AFRO's Professor Dick Chamla said Africa's health systems are not yet fully prepared for these overlapping threats. Preparedness capacity across Africa remains at about 50%, well below the roughly 80% level considered optimal.