Shining light at night could suppress mosquito bites

Cape Town – Exposing malaria-transmitting mosquitoes to light at two-hour intervals during the night or at late daytime could inhibit their biting behaviour and reduce malaria transmission, says a study. A 2016 report of the World Health Organization says that 214 million people worldwide were infected with malaria in 2015, resulting in 438,000 deaths, with 88 per cent of the cases and deaths occurring in Africa.

According to researchers from the University of Notre Dame in the United States, the development of resistance to insecticides requires innovativeapproaches for controlling the malaria vector.

Therefore, they explored the potential of using light to target feeding times of mosquitoes by exposing Anopheles gambiaemosquitoes — a key vector of malaria in Sub-Saharan Africa — to multiple pulses of bright light, especially in the night to help control their feeding behaviour.

“When we subjected the mosquitoes to a series of pulses of light with a two-hour interval and presented throughout the entire night, we observed suppression of biting activity during most of the night,” says Giles Duffield, a co-author of the study published in the journal Parasites & Vectors last month (16 June).

Giles, an associate professor of biological sciences at the University of Notre Dame, tells SciDev.Net that the finding was most prominent during the early to middle of the night and at dawn, phases of the night when people are least protected by the barrier of a bed net.

“Conversely, biting levels were significantly elevated when mosquitoes were exposed to a dark treatment during the late day, suggesting that light suppresses biting behaviour even during the late daytime,” the researchers note in the paper.

This is an interesting study, says Maureen Coetzee, director, Wits Research Institute for Malaria, at Witwatersrand University, South Africa.

But Coetzee notes that most Africans live in rural areas with no electricityand thus a lighting system would have to be set up using batteries or a generator, making the practical implementation of the method a bit challenging.

“I wonder how many people would be able to afford to set this up themselves, and I can’t see governments providing such equipment,” she tells SciDev.Net.

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By Munyaradzi Makoni

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