Abstract
Aedes aegypti (L.) is an important mosquito vector of emerging arboviruses such as Zika, dengue, yellow fever, and chikungunya. To quell potential disease outbreaks, its populations are controlled by applying pyrethroid insecticides, which selection pressure may lead to the development of insecticide resistance. Target site insensitivity to pyrethroids caused by non-synonymous knockdown resistance (kdr) mutations in the voltage-gated sodium (NaV) channel is a predominant mechanism of resistance in mosquitoes. To evaluate the potential impact of pyrethroid resistance on vector control, Ae. aegypti eggs were collected from eight mosquito control operational areas in Harris County, Texas, and emerged females were treated in field tests at four different distances from the pyrethroid Permanone 31–66 source. The females were genotyped by melting curve analyses to detect two kdr mutations (V1016I and F1534C) in the NaV channel. Harris County females had higher survivorship rates at each distance than the pyrethroid-susceptible Orlando strain females. Survivorship increased with distance from the pyrethroid source, with 39% of field-collected mosquitoes surviving at 7.62 m and 82.3% at 22.86 m from the treatment source. Both the V1016I and F1534C pyrethroid resistant genotypes were widely distributed and at high frequency, with 77% of the females being double homozygous resistant (II/CC), this being the first report of kdr mutations in Ae. aegypti in Harris County. Analysis of the probability of survival for each mutation site independently indicated that the CC genotype had similar probability of survival as the FC heterozygous, while the II genotype had higher survival than both the VI and VV, that did not differ. The double homozygous resistant genotype (II/CC) had the highest probability of survival. A linear model estimated probability of survival for areas and genotypes. The high frequency and widespread distribution of double-homozygote pyrethroid-resistant Ae. aegypti may jeopardize disease vector control efforts in Harris County.
Highlights
Aedes aegypti (L.) is the most successful primary vector of emerging and reemerging arboviral diseases which include Zika, dengue, chikungunya, and yellow fever [1]
The objectives of this study were to determine: first, the susceptibility of Ae. aegypti females collected in eight operational areas of Harris County to Permanone 31–66 in field cage tests, where in each test cages were placed at three distances from the applicator path, and second, estimate the frequency of the kdr mutations, valine at position 1016 to isoleucine (V1016I) and F1534C, in surviving and dead mosquitoes from these tests
This study shows that permethrin resistance is present in Ae. aegypti throughout Harris County and most female mosquitoes analyzed had both kdr mutations
Summary
Aedes aegypti (L.) is the most successful primary vector of emerging and reemerging arboviral diseases which include Zika, dengue, chikungunya, and yellow fever [1]. This species is a competent vector for the emerging Mayaro virus (MAYV), which has caused outbreaks in Europe and the Americas [2,3]. Changes in urbanization patterns and climate can influence the distribution of Ae. aegypti, which in turn increases the potential for mosquito-borne disease transmission [7,8]. The primary method of controlling mosquito-borne diseases spread by Ae. aegypti still focuses on controlling adult mosquitoes, often done through insecticide application, and it can be made more sustainable through integrated mosquito management during epidemic seasons [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
