Skip to main content
ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Mosquito and Fly Research » Research » Publications at this Location » Publication #399460
Research Project: Integrated Pest Management of Mosquitoes and Biting Flies

Location: Mosquito and Fly Research

Title: Persistent variation in insecticide resistance intensity in container breeding Aedes co-collected in Houston, Texas

Author
item Estep Iii, Alden
item KISSOON, KIMBERLEY - Harris County Public Health & Environmental Services
item SALDANA, MIGUEL - Harris County Public Health & Environmental Services
item FREDREGILL, CHRIS - Harris County Public Health & Environmental Services

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2023
Publication Date: 5/20/2023
Citation: Estep III, A.S., Kissoon, K., Saldana, M., Fredregill, C. 2023. Persistent variation in insecticide resistance intensity in container breeding Aedes co-collected in Houston, Texas. Journal of Medical Entomology. 51. https://doi.org/10.1093/jme/tjad051.
DOI: https://doi.org/10.1093/jme/tjad051

Interpretive Summary: Strong insecticide resistance in Aedes aegypti has been detected worldwide but strong insecticide resistance in Aedes albopictus is not commonly described. Previous studies have shown that when these species are found together in the same environment, they can have very different resistance profiles but this has not been well characterized. As insecticide resistance can negatively impact the effectiveness of vector control, understanding the resistance profiles of these species is important. In this study, we examined resistance in collections from 4 neighborhoods in Houston TX in 2015. We found that all 4 strains of Aedes aegypti were resistant although of variable intensity. In contrast, Aedes albopictus from the 4 neighborhoods were not resistant. We revisited the neighborhood with the most resistant Aedes aegypti five years later and found that the differences in resistance between species detected in 2015 was still present in 2020 indicating that the differences are persistent, even after being subject to the same control practices. This information can be used to implement more effective mosquito management practices.

Technical Abstract: Resistance to pyrethroids is common in Aedes aegypti in the southern United States and northern Mexico just as in many locations worldwide. Strong resistance in Aedes albopictus is less common and is not as well characterized. These two species have been undergoing range expansion and are now sympatric in many locations like Houston, Texas. They are often collected from the same locations and lay eggs in the same larval habitats. In this study, we colonized both Ae. aegypti and Ae. albopictus from four locations in Houston and then performed insecticide resistance characterization with permethrin as a model pyrethroid. We found differences in resistance intensity between the species at all four sites. Within the Ae. aegypti, resistance ratios ranged from 3.5-30.0-fold when compared to the ORL1952 laboratory susceptible strain. While expression of specific P450s was higher than compared to the ORL1952 strain, they were generally similar between strains of Ae. aegypti. Higher resistance ratios did correlate with increasing percentages of the dilocus knockdown resistance genotype. In contrast, Ae. albopictus from the four locations all had very low resistance ratios (<2-fold) when compared to the same laboratory susceptible strain. To assess the temporal persistence of this difference in resistance between the species, five years later, we performed additional collections and characterization of one of the locations. The same pattern of high resistance in Ae. aegypti and low resistance in Ae. albopictus remain and have implications for operational efficacy.