Warmer Wetter Conditions Drive Surge in Tanzania Disease Outbreaks

Climate change is reshaping Tanzania's disease landscape as warmer temperatures, erratic rainfall and longer humid seasons create conditions for viruses, bacteria and disease-carrying insects to thrive across regions where some diseases were previously rare. Health authorities in late February 2026 urged public caution as cases of respiratory infections, dengue fever and mosquito-borne diseases rose alongside the rainy season.

In Tanzania's Kilombero Valley, flooding from the Kilombero River regularly pushes water into settlements built along its banks, triggering seasonal surges in respiratory infections, malaria and cholera. Chief Medical Officer Grace Magembe noted that surveillance data shows annual increases in severe influenza and COVID-19 between November and April. Dengue fever, transmitted by the Aedes mosquito, has re-emerged particularly in coastal cities including Dar es Salaam and Tanga. Epidemiologist Mbogo Kija observed that outbreaks are becoming less predictable in both timing and geography — with malaria now appearing at higher elevations in Kilimanjaro, Arusha and the Southern Highlands.

The Tanzania Meteorological Authority's director general Ladislaus Chang'a noted that warmer temperatures allow mosquitoes to survive longer and reproduce faster. Both floods and droughts facilitate mosquito breeding: floods create stagnant pools while droughts prompt communities to store water in containers that become breeding sites. Climate change is gradually shifting malaria transmission zones to higher altitudes that historically were too cool to sustain mosquito populations. Crowded temporary shelters during flooding further accelerate transmission of respiratory viruses, compounding the overlapping disease threats.

Public awareness gaps continue to hamper disease prevention. Physicians at Mlimba Health Centre in Kilombero report patients arriving with symptoms resembling malaria that are diagnosed as dengue, a disease transmitted by day-biting Aedes mosquitoes many communities believe only bite at night. Tanzania's health system has historically prepared for seasonal disease increases but is now tracking more complex patterns requiring expanded surveillance and geographic coverage. Health experts call for strong community vigilance, integrated disease monitoring and climate-adaptive public health planning to address the evolving threat landscape.

Key figure — 75 per cent increase in frequency of daily precipitation extremes in Tanzania between 1950 and 2015