With rising temperatures, mosquitoes are also moving to higher altitudes, and scientists fear this could mean an increase in malaria cases.
The temperature range in which malaria-carrying mosquitoes thrive is widening, with researchers finding evidence of the phenomenon from the tropical highlands of South America to the densely populated mountainous regions of eastern Africa.
As the planet warms, mosquitoes slowly migrate upward, the Associated Press (AP) agency reported Thursday, in collaboration with Grist magazine, to explore the intersection between climate change and infectious diseases.
Scientists fear that people living in areas once inhospitable to the insects, including the slopes of Mount Kilimanjaro and the mountains of eastern Ethiopia, may be exposed to the disease.
“As it gets warmer at higher altitudes with climate change and all these other environmental changes, mosquitoes can survive in the mountains,” said Manisha Kulkarni, a professor and researcher who studies malaria in sub-Saharan Africa at the University from Ottawa. .
Kulkarni led a study published in 2016 that found that the habitat of malaria-carrying mosquitoes had expanded in the high-altitude region of Mount Kilimanjaro by hundreds of square kilometers in just 10 years. The lower altitudes, by contrast, are getting too hot for insects.
Similar occurrences have been found elsewhere, and researchers in 2015 also noted that native Hawaiian birds were “pushed” from lower-elevation habitats as avian malaria-carrying mosquitoes slowly migrated into their territory.
But given that 96% of malaria deaths occurred in Africa in 2021, most trend research focuses on that continent.
The region studied by Kulkarni, which is growing in population, is close to the border of Tanzania and Kenya.
Together, the two countries accounted for 6% of global malaria deaths in 2021.
Global deaths from malaria fell by 29% between 2002 and 2021, as countries adopted more aggressive tactics to combat the disease.
However, the numbers remain high, especially in Africa, where children under the age of 5 account for 80% of all malaria deaths.
The latest global malaria report from the World Health Organization (WHO) recorded 247 million malaria cases in 2021: Nigeria, the Democratic Republic of the Congo, Uganda and Mozambique alone accounted for almost half of those cases.
“The link between climate change and the expansion or change in the distribution of mosquitoes is real,” said Doug Norris, a mosquito expert at the Johns Hopkins Bloomberg School of Public Health, who was not involved in the research.
Despite this, uncertainty remains about how changing mosquito populations will affect people in the future.
Mosquitoes are picky about their habitat, Norris added, and the various malaria-carrying species have different preferences for temperature, humidity and rainfall.
Rising temperatures aren’t the only way climate change is giving mosquitoes an advantage, as the insects tend to thrive in the types of extremes that occur most often.
Longer rainy seasons can create better habitats for mosquitoes, which breed in the water.
But conversely, while droughts can make these habitats impossible, they also encourage people to store water in containers, creating the perfect conditions for mosquitoes.
An outbreak of chikungunya, another mosquito-borne disease, between 2004 and 2005 was linked to drought on the Kenyan coast for these reasons.
Source: TSF
