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Towards noon, above the water pooled in a lead-colored bucket, a small toad made of green plastic, with blade-shaped wheels attached to its legs, begins to move and create waves that move gently around it. On top of it is a mini solar cell, and it has bulging eyes that seem to be staring determinedly at a target.
“If the water is agitated, the mosquito is scared away and does not lay its eggs there,” says Dr. Mirko Zimic, from Johns Hopkins University, who is part of a research project for this artificial animal to scare away the harmful mosquito. Aedes aegytpi, the insect responsible for transmitting Zika, chikungunya and especially dengue. The little frog in action, therefore, what it is doing right now is putting the insect to flight in case it appears here.
Zimic explains that the moving frog makes the Aedes aegytpi You see something similar to flashes and flashes, register it in your nervous system as a warning sign and walk away. In the courtyard of the advertising agency VML who acts as one of the promoters of this solution, all this sounds almost magical; but, strictly speaking, it points towards a specific purpose.
Dengue cases have skyrocketed again in Peru dramatically. According to Dr. Palmira Ventocilla, researcher at the Cayetano Heredia Peruvian University (UPCH), The increase so far in 2024 is 251% compared to the previous year. According to the Ministry of Health (MINSA), as of May 24, 236,314 cases had been registered in the country.
In the city of Lima itself, as the specialist points out, cases proliferated to the point that they surpassed those of Piura, one of the departments that reported the most cases. Against this background, the little frog in this story is providential: it is small, practical, it can be placed in any container with water and does not need to be charged with electricity.
Dr. Ventocilla maintains that the system can work, although it has to be accompanied by an ‘educational package’ that tells people that the essential thing is to avoid having containers of stagnant water, since this generates mosquito breeding sites. But if it is unavoidable, the frog placed in the water will fulfill its function of scaring away the Aedes aegytpi.
“It is aimed at human settlements, at people who receive water through tanker trucks,” explains Carlos Tapia of VML, one of the officials of this company, who summoned Zimic, an expert in biophysics, and Fernando Pérez Riojas, industrial designer of the Pontifical Catholic University of Peru (PUCP). Together, they gave life to the ‘Sapolio toad’ or Guardian Toad.
Sapolio is a well-known disinfectant brand in Peru. It already had a little frog on its label, but in the search to expand the social vision of the company, such an image was connected with something that would contribute to facing a problem that was coming with force. As Din Sánchez, general creative director of the agency, recalls, “it was known that dengue was going to become uncontrollable.”
Move against dengue
The resource of moving water to prevent the proliferation of mosquitoes was not so unknown. It is used in the Disney World park in Florida, which is surrounded by swamps, so that visitors do not get eaten by insects. There, all the waters of the facility are in constant movement, something that Luis Días and Juan Carlos Arica, two young creatives from VML, realized.
The problem was how to transfer this system to a country like Peru and, above all, to urban areas where poverty, lack of drinking water and sanitation are rampant. On that route, Zimic confirmed the scientific effectiveness of the water movement mechanism to scare away the insect, in a test carried out on a farm in Chincha, a city located 200 kilometers south of Lima.
It was tested with a jet of water launched from a certain height on the surface of the container. Then, injecting pressurized air, to a depth of five centimeters. And, finally, with a mechanical agitation system that produced vibrations. “The three methods worked well,” says the biophysics expert, clarifying that the last one had the advantage of operating with less energy.
From that, it was defined that the little frog that moves water mechanically thanks to paddles could work. And Pérez dedicated himself to the task of creating an initial model ‘prototype’ (which could later have some variations). It wasn’t easy, according to him. “Its form and expression had to be defined. Determine the type of energy he was going to use so that he could move.”
Solar energy was chosen because it is free and continuous (the mosquito acts during the day, biting in the morning). Furthermore because the Aedes aegytpi It appears more strongly, precisely, at times when the sun shines. As long as sunlight falls on the cell on the frog’s back, the small motor next to it operates its locomotion system.
This consists of two small wheels with paddles located on each side of the body, which move the water. Before, Pérez points out, turbines, propellers and other systems were tested, but they were no better. A complete design task, which also involved a 3D printer that created the first mold of what would later be ‘The Guardian Toad’.
For greater reach
What, strictly speaking, the toad does is dissuade the female from Aedes aegytpi to deposit its eggs on the walls of the container close to the surface of the liquid. Its task is to agitate the water in such a way that the insect does not even come close. The tests carried out in Chincha revealed, as Zimic explains, that this agitat
ion device has an effectiveness of 92%
Álvaro Rojas, vice president of marketing at Alicorp, the company that produces Sapolio, says that they will ensure that the product is “viable, low-cost and widespread.” The company is exploring how to spread the product, either as a gift or through some exchange system. “We want to have a social vision regarding this problem,” he adds.
Rojas adds that, to carry out this entire campaign, it is possible that they will have to make an agreement with the MINSA or with another company. So far, the results found by Zimic in the tests carried out and the functionality of the toad created by Pérez suggest that The Guardian Toad could become massive and contribute to neutralizing the spread of dengue.
In the poorest places in Lima and other cities, where electricity does not reach and water accumulates in buckets because there is no pipe network, this artificial animal is emerging as an option. Once the health protocols are confirmed, it will be enough to put it under the sun to fulfill its function of scaring away those mosquitoes whose larvae leave a dangerous footprint.
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