East Africa: Warming brings malaria mosquitoes to the highlands
The increase in mean temperatures in the East African highlands by half a degree over the past fifty years has simultaneously led to a rise in the region's malaria case count.
This is the result of a study by Mercedes Pascual from the University of Michigan in Ann Arbor, who, together with colleagues, re-examined the data from four climate stations in the area. Between 1950 and 2002, their readings revealed a significant increase in temperature of 0.5 degrees Celsius. The researchers then used a mathematical model to check whether this supposedly low warming is already sufficient for malaria mosquitoes such as Anopheles gambiae to be able to colonize the previously largely malaria-free highlands permanently and in large numbers.
According to these calculations, the survival and reproduction conditions of the insects improved significantly at this point, which subsequently resulted in correspondingly larger insect populations. However, it was not only this purely numerical increase that caused the sharp increase in malaria diseases in East Africa, but also the extension of the mosquito season, which was also triggered by warming.
Previous studies, on the other hand, could not identify any connection between rising temperatures and the increase in malaria cases. Pascual and her colleagues also concede that climate change with its rising temperatures may not be the only or at least the main reason for this increase: However, in their view, its involvement is now certain.