Efforts to eliminate malaria are at a “crunch point” as climate change drives a deadly surge in cases, the World Health Organization has warned.
In its annual World Malaria Report, the agency said malaria is “driven by the environment” and is especially sensitive to temperature, rainfall and humidity.
Where evidence on the direct long-term effects of climate change on malaria is scant, the WHO said climate change may make malaria seasons longer, affecting the accurate timing of seasonal interventions.
Climate is also related to the spread of Anopheles stephensi, the malaria-carrying ‘super mosquito’ famous for surviving in high temperatures in dry seasons, when malaria transmission typically dips.
Some of the strongest data, from the African highlands, shows how rising temperatures have triggered the establishment of malaria in areas that didn’t previously harbour the disease.
Between 3.3 and 3.6 billion people currently live in areas that are highly vulnerable to climate change. The report found that climate change is also fuelling a rise in the frequency and intensity of extreme weather events in some regions.
A severe monsoon season in Pakistan in 2022, which caused widespread flooding, was aggravated by climate change, says the WHO.
Post-flood standing water became a breeding ground for mosquitoes and the spread of disease, and malaria cases jumped five-fold compared to 2021, from 500,000 to 2.6 million.
“We’re at a crunch point. We do have some great and powerful new tools, whether it’s the vaccines or the insecticide-treated mosquito nets, to fight this disease. “[But] the context in which we are facing this disease is becoming ever more challenging,” said Peter Sands, executive director of The Global Fund.
The WHO’s latest malaria report found that there were 249 million malaria cases globally in 2022, having jumped from 233 million in 2019.
The pandemic was instrumental in this, reversing several years of progress that had been made in tackling the disease. Significant disruptions to malaria services, such as the distribution of bed nets, were seen throughout 2020 and 2021.
This caused a spike not just in malaria incidence but mortality rates.Dr Michael Charles, CEO of the Partnership to End Malaria, an NGO, called for a dramatic increase in funding for the malaria response.
In 2022, a sum of $4.1 billion was invested globally to fight malaria – far short of the WHO’s $7.8 billion target.
“We need to invest drastically, because we know there are shortfalls when it comes to the fight against malaria,” said Dr Charles.
‘We’re now at a crux’
The WHO Global Technical Strategy for malaria 2016-2030 aims to reduce malaria mortality and case incidence by at least 75 per cent by 2025 and at least 90 per cent by 2030.
In addition to extreme weather events, other trends are complicating the task of eliminating malaria.
“Malaria is not a disease where you can keep a steady path, you are either winning or losing and we’re now at a crux, where we’re certainly not winning in the way that we need to be,” said Mr Sands.
Mr Sands said he was “very concerned” by the development of resistance; both in terms of mosquitoes becoming resistant to insecticides and the malaria parasite becoming resistant to artemisinin, the main drug used to treat the condition.
“That is why [insecticide-treated] bed nets are such an important innovation and it’s crucial we get those out to protect people as fast as we possibly can,” he said.
“We need to be moving faster than we are to respond to this.”
There are, however, also grounds for optimism. The first WHO-recommended malaria vaccine, RTS,S/AS01, is being rolled out and is available in three African countries, Ghana, Kenya and Malawi, and has already reached 1.7 million children.
The vaccine has proved to be effective, resulting in a substantial reduction in severe malaria cases and a 13 per cent decrease in early childhood deaths in areas where the vaccine had been administered.
Malaria elimination has also been achieved in several ‘low-burden’ countries including Azerbaijan, Belize and Tajikistan. In 2022, 34 countries reported less than 1,000 cases of malaria compared to just 13 countries in 2000.
“Sustainable and resilient malaria responses are needed now more than ever, coupled with urgent actions to slow the pace of global warming and reduce its effects,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General.
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