Small enterprises in São Paulo State develop novel strategies to combat Zika virus

Brazilian entrepreneurs will produce insect repellents based on new natural compounds and traps to capture Aedes aegypti vector mosquitoes, among other solutions.

By Elton Alisson  |  Agência FAPESP – Strategies for combating Zika virus and Aedes aegypti, the vector mosquito, will be reinforced in the coming months. With support from FAPESP and the Brazilian Innovation Agency (FINEP), six small enterprises based in São Paulo State, Brazil, will develop both insect repellents using new natural compounds and traps to capture the mosquito, among other solutions. Besides Zika, A. aegypti also transmits dengue, chikungunya and yellow fever.

The firms were selected in a call for proposals (fapesp.br/10050, in Portuguese) issued by FAPESP and FINEP under the research funding agreement between FAPESP (through its PAPPE Grant Program) and the Ministry of Science, Technology, Innovation & Communications (MCTI), to which FINEP is subordinated. The result of the call (fapesp.br/10710, in Portuguese) was announced at the end of January.

“We were already developing the product, regardless of selection in the call for proposals, but with funding from FAPESP and FINEP we can bring it to market much more quickly,” Bruno de Arruda Carillo told Agência FAPESP. Carillo is a director of DC Química, one of the firms selected in the call.

The firm’s repellent uses rhamnolipid, a compound produced by bacteria such as Pseudomonas aeruginosa.

Rhamnolipid is a widely used biosurfactant, a substance of natural origin that reduces the surface tension or elasticity of a liquid and enhances the emulsification of compounds with different polarities (polar and non-polar) via electronegativity. Its main applications are in manufacturing, mainly of cleaning products such as detergent (given its capacity to emulsify immiscible substances such as oil and water) and cosmetics, among others.

Research findings in recent years have shown that rhamnolipid is also an effective larvicide and insect repellent.

The firm’s researchers performed preliminary tests to confirm the molecule’s known properties. However, tests of its application as a larvicide to kill larvae of A. aegypti did not produce satisfactory results, so the firm decided to test its effectiveness as a repellent.

“We did some initial tests, and the results were very good,” Carillo said. “We estimate that in two years, we can supply samples to manufacturers interested in producing repellent based on this compound.”

Repellency time

One of the main technological challenges to using rhamnolipid as a repellent, Carillo explained, is achieving the same repellency time as for conventional raw materials.

The synthetic molecule DEET (N,N-diethyl-m-toluamide), which is the basis of most insect repellents currently on the market in Brazil, affords protection for up to two hours. Icaridin – a substance derived from pepper that is used in the formulation of repellents recently launched in Brazil – can be effective for up to ten hours, provided that the temperature is not more than 30 °C and that the user does not wash it off.

The problem is that because DEET is toxic, it can only be applied three times per day, affording up to six hours of protection, and that icaridin is still very expensive, according to Carillo.

“We haven’t yet reached the minimum repellency time we want to achieve, which is two hours, but we expect to do so by changing the formulation of the product, which will be a liquid,” he said.

Nanomed, a spinoff incubated at the University of São Paulo (USP), plans to produce a repellent that lasts eight hours per application using essential oil of clove (Eugenia caryophyllata).

To do this, the firm’s researchers will encapsulate the molecule in particles at the nanometric scale (a billionth of a meter) so that its release can be controlled, ensuring repellency for eight hours, which is impossible today using conventional formulations.

“Clove oil is highly volatile, easily evaporating when exposed to air, so it doesn’t last very long at normal temperatures,” said Amanda Luizetto dos Santos, a director of Nanomed.

Home-made insect repellent based on a blend of clove oil and alcohol, for example, is effective for only 30 minutes, she explained. To extend repellency to eight hours, the firm plans to encapsulate the natural compound in nanoparticles that break down gradually, releasing the active ingredient in a controlled and modulated manner, similarly to the nanoparticles and microparticles produced today to encapsulate fragrances in fabric softeners and cosmetics.

“Our goal is both to offer the encapsulated active ingredient as raw material and to develop end-products based on it in the form of cream and aerosol,” Santos said.

Mosquito trap

Instead of repelling A. aegypti, another firm, called Bio Controle, plans to attract female mosquitoes, especially pregnant ones, and capture them in traps to stop them from reproducing and proliferating.

The insects will be attracted to the traps by synthetic chemical compounds, such as fatty acids that mimic human odors, as well as light with specific intensities and colors.

The idea is that the mosquito will be attracted to the trap by the chemical, which will be released in a controlled manner, and will then stick to the trap’s adhesive surface.

“We’ve already developed and marketed a range of traps using synthetic sex pheromones for monitoring and mass collection of various insects that attack agricultural crops,” said Mário Yacoara de Menezes Neto, a director of Bio Controle.

“Our aim now is to test other synthetic chemical compounds to attract A. aegypti mosquitoes and trap them more simply and practically.”

With the funding from FAPESP and FINEP, the firm intends to develop prototypes of traps that can be used by both public health workers and the general public.

“The traps will be non-toxic, so they won’t need regulatory approval in order to be sold,” Menezes said.

Serological test

The firm Barth/Inovatech plans to develop an inexpensive rapid serological diagnostic test for Zika virus using an ELISA platform, mainly for supplying the Ministry of Health.

To achieve this goal, researchers linked to the firm are modifying some of the more expensive molecular biology techniques used in existing diagnostic tests.

“A diagnostic Zika virus kit for 100 samples developed by a foreign firm costs between four and six thousand reais (BRL) in Brazil. We plan to develop a test for the same number of samples that will cost between 1,200 and 1,700 BRL,” said lead researcher Danielle Bruna Leal de Oliveira Durigon.

The call was open to researchers linked to Brazilian micro, small and medium enterprises headquartered in São Paulo State.

The proposals complied with the rules of FAPESP’s Innovative Research in Small Business (PIPE) program.