Location: Mosquito and Fly ResearchTitle: Resistance status and resistance mechanisms in a strain of Aedes aegypti (Diptera: Culicidae) from Puerto Rico Author
|Estep, Alden - Navy Entomology Center Of Excellence|
|Waits, Christy - Lovelace Respiratory Research Institute|
Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2017
Publication Date: 11/7/2017
Citation: Estep, A.S., Sanscrainte, N.D., Waits, C.M., Louton, J.E., Becnel, J.J. 2017. Resistance status and resistance mechanisms in a strain of Aedes aegypti (Diptera: Culicidae) from Puerto Rico. Journal of Medical Entomology. 54(6):1643-1648. doi:10.1093/jme/tjx143.
DOI: https://doi.org/10.1093/jme/tjx143 Interpretive Summary: Scientists at the Center for Medical, Veterinary and Agricultural Entomology and collaborators characterized the insecticide resistance status of a San Juan, Puerto Rico strain of the Yellow fever mosquito, to a variety of available pesticides and the mechanisms for the resistance. This strain is available from CDC as reference strain thus the resistance profile is critical information.
Technical Abstract: Puerto Rico (PR) has a long history of vector borne disease and insecticide-resistant Aedes aegypti (L.). Defining contributing mechanisms behind phenotypic resistance is critical for effective vector control intervention. However, previous studies from PR have focused on only one mechanism of pyrethroid resistance. This study examines the contribution of both enzymatic detoxification and kdr mutations to the overall resistance phenotype of Aedes aegypti collected from San Juan, PR in 2012. Screening of a panel of toxicants found broad resistance relative to the lab susceptible Orlando (ORL) strain. We identified significant resistance to representative Type I, Type II, and non-ester pyrethroids, a sodium channel blocker, and a sodium channel blocking inhibitor, all of which interact with the sodium channel. Testing of fipronil, a chloride channel agonist, also showed low but significant levels of resistance. In contrast, the PR and ORL strains were equally susceptible to chlorfenapyr, which has been suggested as an alternative public health insecticide. Molecular characterization indicated that two common sodium channel mutations were fixed in the population. Topical bioassay with synergist and expression level screening of cytochrome P450s and glutathione-S-transferases indicated some contribution from enhanced enzymatic detoxification. This represents the first study of Puerto Rican Aedes aegypti to examine the contribution of both kdr genetic changes and enzymatic detoxification in the same strain and highlights the necessity of monitoring for resistance and defining resistance mechanisms to inform effective mosquito control.