An affordable method developed by a Mexican researcher to control the population of the Aedes aegypti mosquito (which transmits viruses like dengue and Zika) has shown potential as an effective tool to stop the spread of disease.
The innovation, funded by Grand Challenges Canada, consists in a trap made of discarded tires to capture the eggs of female mosquitoes. This trap, called “Ovillantas” (a composite of two words in Spanish: egg and tire), has been tested in a remote area of Guatemala’s Peten with very promising results, according to its designer Gerardo Ulibarri.
Ulibarri and his two collaborators, Angel Betanzos and Mireya Betanzos, researchers at the National Institute of Public Health of Mexico, reported that 18,100 Aedes aegypti eggs were collected and destroyed per month over a period of 10 months in seven neighborhoods at Guatemalan town of Sayaxché. This figure is almost seven times higher than the 2,700 eggs collected monthly using current methods.
Furthermore, using the method developed by Ulibarri, who is an associate professor at Laurentian University in Canada, costs 33 percent less than destroying mosquito larvae in natural ponds and 20 percent cheaper than using pesticides to kill adult insects.
Ulibarri said that Ovillantas is an adaptation of a trap developed at Laurentian University to combat the spread of West Nile virus, which is also transmitted by mosquitoes.
In the case of Ovillantas, the trap to capture mosquitoes is made of used tires because Aedes mosquitoes naturally choose these containers in 30% of the cases to reproduce, Ulibarri said. In addition, there are a lot of used tires available Guatemala and in this way they can be reused.
The tire is cut in half and a valve is installed in each semicircle. The tire is filled a liquid with the mosquito’s pheromones, developed by the Laurentian University to attract female mosquitoes, in which a paper or wood floats, where the mosquito can deposit the eggs.
The floating paper or wood is removed twice a week to analyze the eggs and destroy them. Also, the liquid is filtered through the valve installed in the tire and is deposited within the trap once again.
“During the period we used the Ovillantas, there were no cases of dengue in Sayaxche. While in nearby towns such as La Libertad or Las Cruces, there were many cases of this disease,” said Ulibarri.
The expert also said that much of the success of the method lies in recycling the liquid with pheromones that attracts female mosquitoes to the trap.
“In other similar traps, the liquid is discarded each time the eggs are collected. But by reusing it, the solution is increasingly powerful and their ability to attract mosquitoes increases,” said the Mexican researcher.
Peter Singer, Director of Grand Challenges Canada (GCC), believes that the method of Ulibarri has great potential to control the population of Aedes and help fight diseases it transmits, including dengue, chikungunya, Zika, and yellow fever.
“The next step is that the method and results are reviewed by other researchers. The relationship between Ovillantas and the absence of dengue cases in Sayaxché is anecdotally at this time. But it’s definitely a very promising sign,” Singer said.
“We are now discussing with Dr. Ulibarri about testing it in other places. GCC is very interested in this method,” added Singer.
Ulibarri added that other areas of the Guatemalan department of Petén have expressed much interest in using the Ovillanta; and they are planning to use in the towns of Las Cruces and La Libertad, as well as in communities in southern Mexico.
Source: Agencia ID