Toxicity of nanoparticles on pyrethroid-susceptible and pyrethroid-resistant larvae of the yellow fever mosquito Aedes aegypti

Research Poster
Erick Marti­nez Rodriguez
Research Scientist
Peter Piermarini
Department of Entomology

The yellow fever mosquito Aedes aegypti, one of the deadliest animals on the planet, transmits several important arboviruses to humans, including Zika, chikungunya, dengue, and yellow fever. Chemical insecticides, such as pyrethroids, have been heavily used to control mosquito populations, however insecticide resistance has forced scientists to find new alternatives for their control. Nano particles (NPs), novel nano carrier systems with a wide range of applications in science and industry, have previously been shown to have toxic effects on mosquito larvae. The aim of this study was to evaluate the effects of a commercially-available NP on acute larval mortality and life cycle development of pyrethroid-susceptible (PS) and pyrethroid-resistant (PR) strains of Ae. aegypti.  We hypothesized that the NP would have concentration-dependent larvicidal activity and/or delay larval development in both strains of Ae. aegypti. To test our hypothesis, we first generated a concentration-response curve of larval mortality. The median lethal concentration (LC50) of the NP after 48 h was 0.44 mg/ml and 0.69 mg/ml for the PS and PR strains, respectively. Next, we daily monitored larval development at three different concentrations of NP (0.25, 0.1, and 0.01 mg/ml) over 14 days. The NP exhibited concentration-dependent mortality in both strains within the first 5 days of exposure, but after this period, the surviving larvae did not show delays in their development to adults.  Our results suggest that NPs have potential use as larvicides for controlling PS and PR mosquitoes. Further research is necessary to determine NPs mode and mechanism of insecticidal action.