Using Light To Crush Malaria

Bill Gates once said, "There are more people dying of malaria than any specific cancer." Many strategies have been employed to lessen the horror of the disease, but a new one may be the simplest and most cost-effective of all: light.

The superb and frustratingly effective combination of Anopheles and Plasmodium has devastated much of the tropical world since before recorded history. In 2015, 730,000 people died of malaria worldwide and almost 3 million people were infected. The death rate for children is appallingly high. Today, 90 percent of all malaria deaths and cases occur in Africa, which loses $20 billion a year due to the health and societal costs of the disease.

Into the fray comes a team of scientists from Notre Dame University, the latest to tackle the ongoing human challenge of malaria control.

According to Photonics, Giles Duffield, an associate professor of biology, studied circadian rhythms and attacked the malaria problem from a wholly new angle. Professor Duffield and his team, headed by lead author Aaron Sheppard, are trying to turn Anopheles' biology against it by disrupting the very rhythms that dictate the insect's life.

The team ran experiments in which Anopheles gambiae Pimperena strain mosquitoes were subjected to various regimens of light bursts. For example, in one experiment, mosquitoes were subjected to one 10-minute light pulse in the early evening.

The researches then pressed their own arms against a gauze and allowed the (non-infected) mosquitoes to bite them at timed intervals. The mosquitoes were then anaesthetized with carbon dioxide gas and their stomachs analyzed for blood.

In this experiment, remarkably, the biting behavior of the mosquitoes was significantly less after the pulse but also after 2 and 4 hours. The research team was surprised how long the effect of the light pulse repressed their biting behavior.

The team varied the timing and length of the pulsed light. They found that if a burst of light disrupts mosquitoes at night, biting behavior almost ceases immediately. If pulses continue all night, biting nearly ceases as well.

The results were definite and astounding -- flashes of light in the early evening or throughout the night seriously reduced the biting behavior of mosquitoes. The team wants to test lights of various wavelengths, too. There is no need to wake a person up with flashing lights if an infrared flash will do.

Insecticides and mosquito netting have reduced malaria in recent years, but it still ravages the tropical world. Can it be that the correct application of the right pulse of light at the right time can disrupt the natural rhythm of the nefarious carrier of deadly Plasmodium?