Artificial light could become a new weapon in the fight against malaria

The world has not yet won the war against malaria. While the total number of cases fell from about 81.1 cases per 1,000 population to 59 per 1,000 since 2000, there were still about 240 million cases and 600,000 deaths in 2020 worldwide.

Malaria remains a threat across Africa. The continent bears by far the greatest disease burden: 94% of cases and 96% of deaths occur across the continent. Alarmingly, children aged five and under make up 80% of these deaths.

There is no room for complacency. Whereas vaccines look promising, there is still a steady increase in resistance to antimalarial drugs, especially in East Africa. The pests evolve mutations that allow them to escape routine diagnosis. Mosquitoes are also evolving more and more insecticide resistance.

This situation highlights the need to refine multiple vector control options and explore new strategies.

My research explores one such potential strategy: the use of artificial lights to trick species of malaria-transmitting mosquitoes that feed at night into behaving as if it were daytime. This can deter feeding, helping to protect people from the bites of malaria-carrying mosquitoes.

new light

Light is a fundamental signal in nature. It regulates much of the timing of biological events, such as bird breeding, lion hunting, and human sleep patterns. It is also an ancient tail. While species have been exposed to changes in climate cycles over eons, the synchronization of day and night has remained relatively constant throughout evolution, due to the rotation of the earth. This means that all life on the planet has evolved with such regular day-night cycles. The gene of melatonin hormonewhich regulates sleep-wake cycles, is shared between very different and ancient taxonomic groups, such as plants and animals.

However, these natural dark cycles are rapidly changing because people are using artificial light more and more. Almost 80% of the planet’s inhabitants now live under artificially lit skies.

So what impact could such use of artificial light have on malaria?

Altering Mosquito Biology

The Anopheles group of mosquitoes, responsible for all cases of malaria in Africa, feed at night. After mating, the females will seek out a blood meal. In doing so, they transfer Plasmodium parasite responsible for malaria. This is why mosquito nets are so effective when used correctly – they block bites when people sleep at night.

Emerging researchincluding mine, argue how artificial light at night can alter mosquito behavior.

Indeed, the artificial light used in homes can alter the biology of mosquitoes. For example, a short pulse of light-emitting diode (LED) light, lights commonly used in homes as “downlights” or reading lamps, can delay the onset of bites by several hours in Anopheles, thereby reducing biting rates and transfer of malaria. The light basically tricks the mosquitoes into not feeding.

These ideas are promising. But vector control strategies don’t always work on a larger scale, especially if those strategies aren’t applied properly. For example, mosquito nets treated with mosquito repellents are sometimes used as fishing nets in parts of Africa. Demonstrating the effects of artificial light in controlled laboratory environments is one thing, but deploying their use as an effective vector control strategy is another.

Even if governments could easily install LED lights in many homes to guard against malaria-carrying mosquitoes, there could be unintended consequences for human health. a bud research body studies the effects of artificial light on human health. Early indications are that it can have negative effects like disturbed sleep.

A growing body of research

Overall, it is not yet clear how artificial lights could be used to reduce the risk of malarial infections. But the growing body of work on this issue suggests it’s a concept that needs more attention from the World Health Organization and other groups.

Once the impacts of using artificial light are better understood, development planners across Africa may be able to ensure that lights of the right type, used in optimal places and times, are part of the continent’s efforts to control malaria.