Why malaria remains one of the world’s deadliest diseases

Despite having one of the best elimination tool boxes in terms of advancement, billions of shillings spent and two new vaccines developed with hope of elimination, malaria continues to claim at least 608,000 lives every year.

But why?

According to Dr Bernard Ogutu, chief research officer with the Kenya Medical Research Institute (Kemri), despite advancements that have led to a 35 per cent reduction of malaria in the past 20 years, the best way to prevent malaria is to prevent mosquito bites.

“Mosquitoes have become smarter, evasive and more tactical as we have observed that some species now bite more during the day,” the expert notes.

He explains that climate change has become one of the greatest threats to human health as it drives both direct and indirect effects on the transmission and burden of malaria.

“In many endemic regions, rising temperatures are leading to longer malaria transmission seasons, increasing the durations during which populations are at risk,” Dr Ogutu tells Healthy Nation.

“A slight warming in cooler, malaria-free zones could lead to ideal conditions for mosquito breeding and survival.”

These changes not only threaten to increase malaria incidence where the disease is endemic but also pose the risk of introducing the disease into new areas where populations lack immunity and health systems are unprepared for outbreaks.

As a result of the climate crisis, excessive floods and heavy rainfall cause more ‘standing water’, which creates ideal breeding grounds for mosquitoes.

Dr Ogutu further points out that drought can also bring about more standing water by halting the flow of rivers and streams.

Secondly, malaria prevention and treatment are essential tools for eliminating malaria yet emerging resistance among mosquitoes and parasites threatens both.

He explains that this is why the World Health Organization(WHO) has outlined four areas of concern in its 2023 strategy that aims at responding to antimalarial drug resistance in Africa. 

“Partial resistance to artemisinin has emerged in Eastern Africa countries, Horn of Africa and Greater Mekong Subregion. This means that though artemisinin-based combinations remain efficacious, there are reports of delayed parasite clearance time, which means cure rates are now lowering below the 90 per cent threshold set by WHO.”

Given the heavy reliance on artemisinin-based therapies on the continent, he says that scientists are worried because high treatment failure rates could have serious consequences that impede efforts to control malaria.

The third reason is rising resistance to insecticides.

According to scientists, resistance to pyrethroids is a threat because of its widespread use on insecticide-treated nets.

Between 2010-2020, 78 countries confirmed mosquito resistance to at least one insecticide class; with Western Africa leading the list of those affected.

Further, genetic mutations are now preventing diagnosis of malaria (pfHRP2/3 deletions).

This is because most diagnostic tests(RDTs) for malaria work by detecting specific proteins by the parasite.

If genetic mutations prohibit the expression of these proteins, the parasite cannot be detected and patients may be at risk of severe disease.

The spread of zoonotic malaria is another reason making the disease deadlier to humans. Plasmodium knowlesi is a zoonotic patrasite with a human fatality rate of one-two per cent and a rapid and severe onset

According to researchers, zoonotic plasmodium infections in humans in many Southeast Asian countries have been increasing, including in countries approaching elimination of human-only malaria transmission.

[email protected]