The plastic toad that moves standing water: Peru’s commitment to fighting dengue | Future America

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As the afternoon approaches, above the water accumulated in a lead bucket, a small green plastic toad with blade-shaped wheels attached to its legs begins to move and create waves that move gently around it. There’s a mini solar cell on top of it, and it has bulging eyes that seem to be staring determinedly at a target.

“If the water is agitated, the mosquito is repelled and does not lay eggs there,” says Dr. Mirko Zimic of Johns Hopkins University, who is involved in a research project to create this artificial animal to repel harmful mosquitoes. Aedes egitpi, insect responsible for transmission of Zika virus, chikungunya virus and especially dengue fever. So the little frog in action is now putting the insect to flight in case it appears here.

Zimich explains that a moving frog Aedes aegytpi You see what looks like flashes and flashes, register it in your nervous system as a warning sign and walk away. In the courtyard of the advertising agency VML, which is one of the promoters of this solution, all this sounds almost magical; but, strictly speaking, it points to a specific goal.

Dengue fever cases have risen sharply again in Peru. According to Dr. Palmira Ventocilla, a researcher at the University of Peru Cayetano Heredia (UPCH), the growth in 2024 will be 251% compared to the previous year. According to the Ministry of Health (MINSA), as of May 24, the country had 236,314 cases.

In the city of Lima itself, the specialist notes, the number of cases has increased to such an extent that they have surpassed those of Piura, one of the departments that reported more cases. Against this background, the frog in this story is providential: it is small, practical, can be placed in any container of water and does not need to be charged with electricity.

Dr Ventocilla says the system can work, although it needs to be accompanied by an “educational package” that tells people it is important to avoid containers of standing water as it creates breeding grounds for mosquitoes. But if this is unavoidable, then a frog placed in water will perform its function of repelling Aedes aegytpi.

“It is aimed at populated areas, at people who receive water in tankers,” explains Carlos Tapia of VML, one of the officials of the company, who called Zimic, an expert in biophysics, and Fernando Pérez Riojas, an industrial designer at the Pontifical Catholic University Peru (PUCP). Together they gave birth to the “Sapolio toad” or Guardian Toad.

Sapolio is a famous brand of disinfectants in Peru. There was already a small frog on the label, but in an effort to expand the company’s social vision, the image was associated with something that would help solve a problem that was looming large. As Dean Sanchez, the agency’s chief creative officer, recalls, “It was known that dengue would become uncontrollable.”

Movement against dengue

The resource of moving water to prevent the spread of mosquitoes was not entirely unknown. It is used at Disney World in Florida, which is surrounded by swamps to prevent visitors from being eaten by insects. There, all the waters of the facility are in constant motion, as Luis Diaz 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 this route, Zimic confirmed the scientific effectiveness of the water movement mechanism to repel insects in tests carried out on a farm in Chincha, a city located 200 kilometers south of Lima.

Its tests were carried out with a stream of water thrown from a certain height onto the surface of the container. Then, pumping compressed air to a depth of five centimeters. And finally, with a mechanical mixing system that produced vibrations. “Three methods worked well,” says the biophysics expert, adding that the last method had the advantage of working with less energy.

From this it was determined that a small frog that mechanically moves water using paddles could work. And Perez devoted himself to the task of creating an initial “prototype” of the model (which could later have some variations). According to him, it was not easy. “It was necessary to determine its shape and expression. Determine the type of energy I was going to use to make it move.”

Solar energy was chosen because it is free and continuous (the mosquito works during the day, bites in the morning). Moreover, since Aedes aegytpi It manifests itself more strongly precisely at those moments when the sun is shining. As sunlight hits the cage on the frog’s back, a small motor next to it controls its locomotion system.

It consists of two small wheels with blades located on the sides of the body that move water. Previously, Perez notes, turbines, propellers and other systems were tested, but they were no better. A complete design challenge that also involved a 3D printer creating the first shape of what would become “Guardian Toad”

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What, in fact, what the toad does is dissuade the female from Aedes aegytpi lay eggs on the walls of the container near the surface of the liquid. Its task is to agitate the water in such a way that the insect does not even come close. Tests carried out in Chinca showed, as Zimich explains, that the efficiency of this mixer is 92%.

Alvaro Rojas, vice president of marketing at Alicorp, which makes Sapolio, says they will ensure the product is “viable, inexpensive and widespread.” The company is exploring ways to distribute the product either as a gift or through some kind of exchange system. “We want to have a social perspective on this issue,” he adds.

Rojas adds that they may have to enter into an agreement with MINSA or another company to carry out this entire campaign. So far, the results obtained by Zimic from the tests carried out and the functionality of the toad created by Perez suggest that the Guardian Toad can become massive and help neutralize the spread of dengue fever.

In the poorest parts of Lima and other cities, where there is no electricity and water accumulates in buckets due to the lack of a running water network, this artificial animal is becoming an alternative. Once the sanitary protocols are confirmed, it will only be necessary to place it in the sun for it to fulfill its function of repelling those mosquitoes whose larvae leave a dangerous trail.