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.
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