LONDON (Thomson Reuters Foundation) – Malaria risks spreading to high altitudes as global temperatures rise and further warming might cause a significant increase in malaria cases in highland regions where malaria is endemic, according to a study published on Thursday.
Unless disease-monitoring and control efforts are boosted and sustained, the disease will spread to new high-altitude areas, making populations living there particularly vulnerable because of a lack of immunity.
“What we show is that the risk rises with the altitude (and) the point is how much control is there: If malaria is fully controlled in a country then you won’t see (the rise in malaria cases), unless you get drug resistance or you stop control,” Menno Bouma, honorary senior clinical lecturer at the London School of Hygiene & Tropical Medicine and one of the authors of the study, told Thomson Reuters Foundation on the phone from Sweden.
In the Debre Zeit region of Ethiopia alone, scientists say about 37 million people are at higher risk of malaria.
“What we can say in Ethiopia is that...it has been a 1 degree (Celsius) rise in temperature already and we have calculated before that a 1 degree increase in temperatures will increase the malaria burden around 50 percent,” Bouma said.
“So considering that the reported number of cases in Ethiopia is around 9 million a year and (there are) 70,000 deaths reported due to malaria…you can estimate that a third of (those cases) could be attributed to the rise in temperatures that it has already occurred.”
Researchers have debated for more than two decades whether global warming has an impact on the worldwide prevalence of malaria, a mosquito-borne disease that infects 300 to 500 million people each year.
“It has been long time expected that (the increased number of malaria cases due to rising temperatures) would happen, but we have so far been unable to prove this unequivocally,” said Bouma.
It had been predicted that malaria could be particularly sensitive to climate change, because both parasites that cause it and mosquitoes that carry it thrive as temperatures rise.
However, some scientists argued that improved socio-economic conditions and effective mosquito-control efforts would have greater influence over the extent and intensity of malaria worldwide than climate factors.