Good Thinking

Fighting the Zika virus with junked tires

Fighting the Zika virus with j...
An ovillanta mosquito trap, originally developed to fight West Nile virus in Northern Ontario
An ovillanta mosquito trap, originally developed to fight West Nile virus in Northern Ontario
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Building an ovillanta trap in Guatemala
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Building an ovillanta trap in Guatemala
An ovillanta mosquito trap, originally developed to fight West Nile virus in Northern Ontario
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An ovillanta mosquito trap, originally developed to fight West Nile virus in Northern Ontario
Checking the bottom section of an ovillanta trap
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Checking the bottom section of an ovillanta trap

Mosquitos like old tires. More specifically, female mosquitos like to lay their eggs in the cool, stagnant water that often accumulates within them. Now, in the fight against mosquito-borne diseases such as the Zika virus, the Government of Canada is using that fact against the insects. Researchers with the Grand Challenges Canada initiative have created a highly-effective mosquito trap, each one of which is made from a single discarded tire.

Known as the ovillanta, the trap is made from two 50-cm (19.7-inch)-long sections of tire, placed together to form a sort of cave. Water is placed in the bottom section, along with a milk-based non-toxic solution that attracts mosquitos. Additionally, a strip of paper is placed within to float on the water.

Female mosquitos subsequently fly into the ovillanta, lay their eggs on the paper, and deposit pheromones in the water to let other mosquitos know that it's a safe breeding site.

Checking the bottom section of an ovillanta trap
Checking the bottom section of an ovillanta trap

The catch is, twice a week the paper is removed and checked for eggs, then burned or sterilized using ethanol. Additionally, using a release valve on the bottom section, the water is drained and any larvae present are filtered out and destroyed. The filtered water is then placed back in the trap for reuse – it becomes more attractive to mosquitos over time, as more and more of the pheromones are deposited and concentrated within it.

In a 10-month field test conducted in Guatemala, a system of 84 ovillantas allowed users to collect almost seven times as many Aedes mosquito eggs as were collected using 84 standard traps placed in the same locations. Additionally, use of the new traps is said to be about one-third the cost of destroying larvae in natural ponds, and about 20 percent the cost of spraying for adult mosquitos – it's also considerably more environmentally-friendly than the latter.

The research is being led by Dr. Gerardo Ulibarri of Ontario's Laurentian University, working with colleagues Angel Betanzos and Mireya Betanzos of the National Institute of Public Health of Mexico. Plans call for a program to be established in which local people, living in areas prone to maladies such as Zika or dengue, will build and maintain the traps.

Source: Grand Challenges Canada

7 comments
Ralf Biernacki
This is a very short-sighted approach. What they are doing is eliminating the offspring of those mosquitoes, and only those mosquitoes, that like to lay eggs in the "ovillantas". Guess what the evolutionary result will be---and that result will be produced quickly, because the selective pressure is very strong and mosquito generations turn over fast. <p>What is really disheartening is that it isn't just ignorant activists, but qualified scientists who are promoting this dead end solution.
piperTom
"The catch is, twice a week the paper is removed and ..." also, water is filtered. Sounds labor intensive. If people fail to maintain their traps, the traps becomes a mosquito booster. I'd say this is fine for a proof of concept and it's cool that it uses recycled tires, but if the idea is ever to see wide scale use, it has to be designed to need very little human interaction.
Jimjam
"twice a week the paper is removed and checked for eggs, then burned or sterilized using ethanol. Additionally, using a release valve on the bottom section, the water is drained and any larvae present are filtered out and destroyed. The filtered water is then placed back in the trap for reuse" That relies on a human remembering to to release the water. How about putting on top a small solar panel, battery, and device that releases a pill into the water twice per week that kills the larvae?
JA Larson
This seems to be more of a monitoring/sampling trap, not a killing/eradication trap. Otherwise, it's too labor intensive. The pheromones have already been duplicated and bacterial larvicides are available.
owlbeyou
I think the big plus of this concept is its affordability and ease of use. These ovillantas won't be deployed up here in Canada or the US. They're for the semi tropics where people actually take the trouble to use and monitor them, unlike us lazy good-for-nothings who'd rather use propane CO2 traps that cost a hell of a lot more.
mediabeing
Ahhh! It all makes sense now! Donny Trump is a Zika victim.
akapapaliif
I agree with the fact that this method is affordable and chemical free; my concern is the proper skills of those who will be using it. I know its really a great idea for the Vector Control unit in the Environmental Health Section, but the worries is how to monitor the trap when its in place. And one comment is true, what if the monitoring is not well looked after for? It will end up with the trap becoming the breeding sites. I would like to suggest if its possible for those colleagues who invented this idea to have a demonstration of the procedures and steps on how to do it from step one till the last point please. Appreciated the great efforts from the Kingdom of Tonga.