Widespread insecticide resistance in Aedes aegypti L. from New Mexico, U.S.A.

Abstract

Background Aedes aegypti mosquitoes are vectors of a variety of emerging viral pathogens, including yellow fever, dengue, chikungunya, and Zika virus. This species has established endemic populations in all cities across southern New Mexico sampled to date. Presently, control of Aedes -borne viruses relies on deployment of insecticides to suppress mosquito populations, but the evolution of insecticide resistance threatens the success of vector control programs. While insecticide resistance is quite common in Ae . aegypti field populations across much of the U.S., the resistance status of this species in populations from New Mexico has not previously been assessed. Results First, we collected information on pesticide use in cities in southern New Mexico and found that the most commonly used active ingredients were pyrethroids. The use of insecticides with the same mode-of-action over multiple years is likely to promote the evolution of resistance. To determine if there was evidence of resistance in some cities in southern New Mexico, we collected Ae . aegypti from the same cities and established laboratory strains to assess resistance to pyrethroid insecticides and, for a subset of populations, to organophosphate insecticides. F2 or F4 generation mosquitoes were assessed for insecticide resistance using bottle test bioassays. The majority of the populations from New Mexico that we analyzed were resistant to the pyrethroids permethrin and deltamethrin. A notable exception to this trend were mosquitoes from Alamogordo, a city that did not report using pyrethroid insecticides for vector control. We screened individuals from each population for known knock down resistance (kdr) mutations via PCR and found a strong association between the presences of the F1534C kdr mutation in the para gene of Ae . aegypti (homologue to F1534C in Musca domestica L .) and pyrethroid resistance. Conclusion High-level pyrethroid resistance is common in Ae . aegypti from New Mexico and geographic variation in such resistance is likely associated with variation in usage of pyrethroids for vector control. Resistance monitoring and management is recommended in light of the potential for arbovirus outbreaks in this state. Also, alternative approaches to mosquito control that do not involve insecticides should be explored.

Reduced effectiveness of repellents in a pyrethroid‐resistant strain of Aedes aegypti (Diptera: culicidae) and its correlation with olfactory sensitivity

“…aegypti (94-fold to permethrin, unpublished data 2019) showed similar topical resistance with the field-collected mosquitoes in Puerto Rico (73-fold to permethrin), 19 the development of resistance to repellents could vary in the field in terms of magnitude and/or mechanism(s). 14,36 Recently, the control of mosquitoes, especially in Africa, is being threatened by pyrethroid resistance. 37,38 The development of this resistance may lead to the failure of other control strategies that are on the horizon (i.e.…”

The need to harmonize insecticide resistance testing: methodology, intensity concentrations and molecular mechanisms evaluated inAedes aegyptipopulations in Central America and Hispaniola

“…In America, kdr mutations have been reported in Ae. aegypti populations from Ecuador, (22), United States (23, 24), Colombia (25, 26), México (27–29), Brazil (30–35), Lesser Antilles (36–40), French Guiana (37), Venezuela (29, 41), Cuba (29, 39), Panamá (42), Puerto Rico (43). This is the first report of kdr mutations for the countries included in this study, except for Haiti (87).…”

“…Resistance to pyrethroids in mosquitoes have been widely associated with the F1534C (21, 23, 25, 27, 29, 30, 32, 39–41, 83, 88–101) and V1016I mutations (24, 25, 27, 29, 30, 32, 36, 38, 40, 41, 88, 93, 97, 100, 102, 103). The simultaneous presence of both mutations has been associated with enhanced tolerance to deltamethrin in the past (31).…”

Programmable CRISPR interference for gene silencing using Cas13a in mosquitoes

“…gambiae G3 strain and Ae. aegypti Puerto Rico strain were obtained from MR4 BEI and maintained using rearing conditions described previously [32,33]. The pAc-Cas13a construct (0.5µg/µl) was delivered into one-day old adult female mosquitoes by intrathoracic injection.…”