Researchers are investigating a common treatment for pet ticks and fleas to target larvae of flies and mosquitoes, aiming to reduce the transmission of diseases spread by these insects.
Researchers are investigating a common treatment for pet ticks and fleas to target larvae of flies and mosquitoes, aiming to reduce the transmission of diseases spread by these insects.
After her dog was switched to fluralaner, a veterinary medication, Emily McDermott—an assistant professor specializing in medical and veterinary entomology and a researcher with the Arkansas Agricultural Experiment Station—became interested in its alternative uses.
“I chose fluralaner for my dog because the spot-on treatments were ineffective,” she explained. “Fluralaner is exciting because it functions differently from the insecticides we usually use.”
This medication disrupts the nervous systems of insects by interfering with their nerve cell function.
According to McDermott, earlier studies suggested positive outcomes when fluralaner was used as a spray; however, it proved significantly more effective when given orally.
McDermott and Ph.D. student Blythe Lawson conducted research to determine if fluralaner could serve as a larvicide and to identify the optimal method for delivering it to the larvae.
By directly administering the treatment to the larvae, they reduced chemical usage and targeted specific areas with high larval concentrations. This approach minimizes widespread spraying and decreases the risk of environmental contamination.
The research titled “Successful yeast microencapsulation of fluralaner and its potential as a larvicide for vector control” was published in the Acta Tropica journal in August.
“Fluralaner is a promising synthetic compound, and interest in its utilization is growing,” Lawson remarked. “The market lacks sufficient larvicides, especially for mosquitoes.”
Diseases like malaria, dengue, and Zika virus are transmitted by flies and mosquitoes. McDermott noted that many disease vectors, including mosquitoes, have developed resistances to commonly used pesticides, and traditional methods often target adult insects. However, Lawson and McDermott explored utilizing fluralaner to focus on the larvae stage before these insects develop into adults, which is when they pose the greatest threat of spreading diseases.
“You can reduce those populations before they start becoming a problem,” McDermott stated.
Fluralaner is available for pets in a chewable form under the brand name Bravecto, which is currently the only form of fluralaner approved for use in the United States.
The Trojan horse method
McDermott and Lawson applied a yeast microencapsulation technique to evaluate fluralaner’s effectiveness. They encapsulated fluralaner within yeast cells and tested it on the larvae of three insect species:
- Common house fly — Musca domestica
- Asian tiger mosquito — Aedes albopictus
- Biting midge — Culicoides sonorensis, prevalent in much of the eastern U.S.
Since these larvae naturally consume microorganisms such as yeast, the microencapsulation method proved advantageous for delivering the insecticide.
“It works like a Trojan horse,” Lawson explained.
The findings indicated that fluralaner is both effective and long-lasting as a larvicide. The study revealed that a single application of the microencapsulated form could control mosquito larvae for up to five weeks and midge larvae for about eight weeks.
“We compared our product to several commercially available mosquito larvicides and discovered that it was at least as effective, if not more so, than those currently available,” noted McDermott.
The research also indicated that a higher concentration is required to eliminate housefly larvae in comparison to mosquitoes or biting midges, which aligns with the fact that houseflies are larger.
Meanwhile, McDermott observed that midges seemed less responsive to the larvicide compared to mosquitoes, a surprising result given that midge larvae are much smaller than those of mosquitoes.
“We suspect that size plays a role in this, but there are also physiological differences among these insects to consider,” she added.
Future Use
McDermott hopes this research will lead to creating a product suitable for use in residential areas and trash collection points.
“Our product formulation involves encapsulating the active compound in yeast, freezing it, and returning it to a powdered yeast state,” she explained. “We envision it being used in a backpack sprayer, similar to other insecticides.”
McDermott indicated her team is collaborating with industry partners to advance this patent-pending technology.
“We’re still several steps away from bringing this to market,” she clarified. “With additional research and development, this yeast-based larvicide can become a new resource for vector-control initiatives and public health.”
This study received support from the Deployed Warfighter Protection Program Award No. W911QY2210003. The DWFP is a research initiative aimed at developing and assessing tools to manage pests and vectors that pose disease risks to deployed military personnel. It is managed by the Armed Forces Pest Management Board and funded by the Department of Defense.
