Thursday April 07, 2016

How this Canadian-designed mosquito trap could help fight Zika virus

(Daniel Pinelo)

Listen 7:42

The design is so simple, you can build one yourself. Here's how: take an old tire, cut it in half, fill it with recycled water, add a cloth filter and hang it on a wall. 

Developed in Canada with government funding, the ovillanta, as it's called, is proving to be an incredibly effective mosquito trap. 

And now, the team of Canadian and Mexican researchers who invented it plan to use it to combat the spread of Zika and other mosquito-borne viruses. Gerardo Ulibarri of Laurentian University is the lead researcher on the project. He explains to As it Happens host Carol Off that mosquitoes need water to lay their eggs. That's where the ovillanta comes in.

"We create an artificial pond in the tire," he says."During the dry season, the mosquitoes will not have many choices where to lay their eggs. So by providing this artificial pond, the mosquitoes will go there. Then we have the rainy season, where mosquitoes have other places where they can go. For that we can use specific attractants to lure the mosquitoes to the ovillanta, or artificial tire."

Hanging ovillanta

The 'ovillanta' mosquito-trap is made by creating an "artificial pond" in a cut tire (Daniel Pinelo)

Once the insects take the bait, so to speak, they "come in and lay their eggs on a wet surface — made out of paper or wood," he explains. 

"All mosquitoes, when they lay their eggs, within the egg there is a microgram of a pheromone. That's what is called an 'oviposition' pheromone. When the larva hatches, it liberates the pheromone into the water — which helps indicate to other female mosquitoes that that's a good place for their babies to be born."

Then, all that's left to do is remove the eggs from the water. The now-pheromone rich trap will continue to attract more mosquitoes.

"Every three [to] seven days, we open the valve and recycle the solution through a filter — made out of a piece of clothing, for instance — so that we can separate, or eliminate, all the larvae and the eggs from the solution...That allows us to recycle the solution, which contains the pheromone that the mosquito has put in."

"The system is very cheap to implement -- probably less than five dollars." - Ovillanta project lead researcher Gerardo Ulibarri

Tests conducted in Canada and Mexico on two types of mosquitoes have so far produced extremely promising results.

"In Sudbury, Ontario, against the Culex mosquitoes...we observed a 90% reduction in the place where we had our traps," says Ulibarri. "The second study was done north of Acapulco in Mexico, in a town called Petatlán, against the Aedes mosquito that transmits the dengue fever. And there we observed about a 70-71% reduction."

Building an ovillanta

Building an ovillanta (Daniel Pinelo)

Of course, the do-it-yourself simplicity of the trap is also a great advantage -- not to mention that it requires no chemicals.

"The system is very cheap to implement -- probably less than five dollars," says Ulibarri. "Other traps will require either a piece of glue, or a glued paper -- or will require some pesticide or larvicide inside. In our case, we have seen frogs inside of the ovillanta, we have seen bees drinking water out of the solution. So it's very ecologically friendly."