The surge in malaria cases in Gauteng this year was not caused by mosquito bites within the province, but rather, linked to people who had visited neighbouring countries and provinces after the January floods in southern Africa, reports Daily Maverick.
More than 400 infections and 11 deaths in the first three months of 2026 had initially caused alarm, and in a public webinar last week entitled “What caused the 2026 spike in malaria cases in Gauteng?”, senior University of Pretoria malaria expert Professor Tiaan de Jager said the cases – reported in Johannesburg and Pretoria – were a shock in a province where the disease was not endemic.
Many of the infected people had complained of flu-like symptoms, not realising until much later that they were suffering from malaria.
De Jager, founding director of the university’s Institute for Sustainable Malaria Control, noted that the 414 cases recorded in Gauteng, in the first quarter of 2026, represented an 80% increase compared with the total number of cases the entire previous year.
Cases in Mpumalanga also rose by 355%, by 68% in Namibia and by more than 50% in Mozambique over the same period.
The underlying cause was the heavy rain in December 2025, followed by floods in January 2026 in the northern parts of South Africa, including Kruger National Park and neighbouring Mozambique, that left behind pools of water which created increased breeding habitat for mosquitoes.
This led to more mosquitoes and more parasite transmission in malaria-endemic regions.
Four to six weeks after being bitten while visiting these regions, more than 400 people in Gauteng began noticing symptoms that were often mistaken for flu, with diagnosis and treatment for malaria coming too late for at least 11 people who died from the infection.
Further imported cases were likely to appear in Gauteng among people travelling to endemic areas, he said.
De Jager also suggests that it is not correct to attribute the Gauteng cases generally to climate change or to the re-emergence of malaria within Gauteng, and that the available surveillance data indicated that “most” of the cases diagnosed in Gauteng had been imported.
On whether it was possible that a limited number of cases were transmitted within Gauteng, he said: “The National Institute for Communicable Diseases (NICD) has confirmed there is no established local transmission. The publicly available reports do not provide any information on locally acquired cases among the 414 cases recorded during January to March.
“Although rare cases can occur when infected mosquitoes are transported into non-endemic areas, this should not be confused with sustained local malaria transmission,” he said.
“Gauteng’s higher altitude and cooler winter conditions are less favourable for sustained malaria transmission, and the province is not considered malaria-endemic. Nevertheless, occasional cases can occur when infected mosquitoes are transported into non-endemic areas. These exceptional cases are different from established local transmission.
“My point is… not that climate change is irrelevant to malaria. Rather, we need to distinguish between climate-related increases in transmission in endemic areas, the subsequent movement of infected people into Gauteng, and the separate question of whether local environmental conditions could support transmission within Gauteng.
“Climate change may increase malaria risk across southern Africa, but the increase in cases in Gauteng should not automatically be attributed to climate change or local transmission. The regional floods, increased transmission in endemic areas, travel patterns and the possibility of occasional mosquito transport all need to be considered separately. In my opinion, climate change will most definitely increase malaria risk.”
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