A new, ingenious device makes mosquito traps out of what the pests normally breed in.
The Aedes aegypti mosquito — the aggressive transmitter of Zika, dengue, yellow fever, and chikungunya —t can breed in even the smallest pools of water. An amount that would fill a thimble is enough.
Discarded tires are a perfect breeding ground as they fill with water when it rains. And there are thousands — if not millions — of them spread all across Latin America where the Zika virus has taken hold. Researchers have estimated Aedes aegypti mosquitoes use tires for almost a third of their breeding sites.
This new device, which we first saw at CIDRAP News, turns those tires into traps.
It’s a prime example of how cheap innovations could be a crucial piece of taking this mosquito down and getting the Zika outbreak under control.
The idea arose when Canadian and Mexican researchers were in Guatemala to teach locals about mosquito control and study ways to kill the bugs.
But they couldn’t get a hold of the devices they usually use to trap, track, and kill mosquitoes, which are called ovitraps. So they decided to improvise.
They cut some old tires, and ended up designing a surprisingly easy-to-make, cheap ovitrap. They called them ovillantas.
To make one, you simply cut a used tire into four pieces (20 inches each), drill a hole in the middle, and insert a PVC pipe with a valve at the end into it.
You fill the tire with water and add papers to each end containing a non-toxic, milk-like mosquito attractant, which the researchers provide in a kit.
Every three days, you simply strain the water through the valve, kill the mosquitoes that were inside by lighting them on fire or dousing them in bleach, then reuse the water. This water now contains pheromones, alerting other female mosquitoes that it’s a good place to breed. Joke’s on them!
And the tire traps are remarkably effective. In a study the researchers published April 7, they reported their ovillantas killed seven times as many mosquitoes as standard traps they set up in Guatemala. (The study has not yet been peer-reviewed, and more research is needed to confirm these results.)
In 10 months, they reported, just 84 ovillantas killed an average of more than 18,000 Aedes aegypti mosquitoes each month.
“We decided to use recycled tires — partly because tires already represent up to 29% of the breeding sites chosen by the Aedes aegypti mosquitoes, partly because tires are a universally affordable instrument in low-resource settings, and partly because giving old tires a new use creates an opportunity to clean up the local environment,” Ulibarri said.
The traps are cheaper than using pesticides to kill mosquitoes, which don’t always work, and can also harm bats and the environment.
With the community outreach the researchers provided, people in Zika-affected areas can make the ovillantas themselves, possibly helping slow the spread of the fast-moving virus.
Correction: This story has been updated to reflect the fact that the ovillantas killed an average of 18,000 Aedes aegypti mosquitoes per month, not over the course of the study.