Here's an idea for killing some of the mosquitoes that infect people with diseases like Zika or malaria: Lure the bugs into a box laced with human scent. Dust them with a deadly fungi or insecticide. Then watch the insects die off as they fail to reproduce.
Researchers tested the device—known as the mosquito landing box (MLB)—in trials in rural Tanzania. Using odors from socks worn for 12 hours as well as artificially created scents, they managed to attract mosquitoes and to contaminate a good deal of them. If commercialized, the MLB could be useful for controlling mosquitoes outdoors, allowing people to sit in the open without fear of getting bitten.
The box contains a solar-powered fan for spreading the scents, as well as jars of molasses and yeast that give off carbon dioxide, mimicking human breath. As reported in the journal paper here, the researchers released 400 laboratory-reared insects into large tents with two MLBs, plus a control box with no scent. Human volunteers also sat in simulating a typical village where people are outside on a summer evening. Sixty-three percent of the insects were contaminated with the insecticide, while 43% were contaminated by the fungi. The control boxes attracted few, if any, insects.
"The sterilized adults won't be able to produce viable eggs," says lead researcher Arnold Mmbando, currently a masters student at the University of Basel, in Switzerland. "[The insecticide] also causes the death of early-stage mosquitos when the adults attempt to deposit their eggs, leading to the death of massive numbers of mosquitos and a reduction in their population densities."
Mmbando says the boxes can attract mosquitos within a roughly 1,000 square feet area. But the device still needs to be tested in full outdoor settings, with different types of mosquitoes and in areas with lower infestations of the insects. At the moment, the MLB costs about $150 to manufacture. But Mmbando thinks it should be possible to bring that down to $40 or less once the design is simplified and produced at scale.
"If we find a good industry partner, we can sell the device to the rest of Tanzania and and also outside Africa," he says. "Through a partnership with the government or funding agencies to subsidize manufacturing, we'll enable the company to produce a massive number of the simplified final prototype and sell for the cheaper price."
Of course, there's a massive need to deal with disease-carrying mosquitos. The Zika virus is in the news right now, and up to 500 million people are infected worldwide with malaria each year; 1 million people died last year from malaria in Sub-Saharan Africa alone.