Sub-lethal insecticide exposure affects host biting efficiency of Kdr-resistant Anopheles gambiae

Abstract

<jats:title>A<jats:sc>bstract</jats:sc></jats:title><jats:p>The massive use of insecticide-treated nets (ITNs) has drastically changed the environment for malaria vector mosquitoes, challenging their host-seeking behaviour and biting success. Here, we investigated the effect of a brief exposure to an ITN on the biting behaviour of <jats:italic>Anopheles mambiae</jats:italic> mosquitoes and the interaction between such behaviour and the <jats:italic>kdr</jats:italic> mutation that confers resistance to pyrethroids. To this aim, we developed a video assay to study the biting behaviour of mosquitoes with similar genetic background, but different <jats:italic>kdr</jats:italic> locus genotypes (SS i.e. homozygous susceptible, RS i.e. heterozygous and RR i.e. homozygous resistant), after a brief exposure to either control untreated nets or one of two types of pyrethroid-treated nets (deltamethrin or permethrin). In presence of untreated nets, the <jats:italic>kdr</jats:italic> mutation did not influence mosquito blood feeding success but caused differences in feeding and prediuresis durations and blood meal size. Exposure to deltamethrin ITN decreased the blood feeding success rate of RR and RS mosquitoes, whereas in presence of permethrin ITN, the <jats:italic>kdr</jats:italic> mutation increased the blood-feeding success of mosquitoes. Exposure to the two types of pyrethroid-treated nets reduced feeding duration, prediuresis duration and blood meal size of all three genotypes. Our study demonstrates a complex interaction between insecticide exposure and the <jats:italic>kdr</jats:italic> mutation on the biting behavior of mosquitoes, which may substantially impact malaria vector fitness and disease transmission.</jats:p>

Influence of GST- and P450-based metabolic resistance to pyrethroids on blood feeding in the major African malaria vectorAnopheles funestus

“…This corroborate with observation previously made for kdr mutation in An. gambiae with lower feeding duration for homozygous resistant mosquitoes than heterozygote and homozygous susceptible [11]. The non-significant result observed may be due to the low number of resistant mosquitoes in the present study.…”

“…The non-significant result observed may be due to the low number of resistant mosquitoes in the present study. However, it could be hypothesized that this result indicates that L119F-GSTe2 mutation might confer an advantage to homozygous resistant mosquitoes as it was previously reported that fast feeding reduces the risk to be kill because of the host defensive behaviour [11,36].…”

“…The volume of blood meal of a mosquito could be affected by a range of intrinsic (host immunity) and extrinsic factors including ambient temperatures, mosquito age, parity status, gonotrophic cycle, blood feeding history and infection status [10]. More recently, it was reported that exposure to pyrethroids could also significantly influence the blood meal process and the blood meal volume ingested by Anopheles gambiae mosquito [11].…”

“…For target-site resistance, a decreased longevity and increased larval development time have been reported in kdr -pyrethroid-resistant mosquitoes [20,21]. Moreover, a recent study suggested that kdr -based resistance could impact blood feeding with heterozygote ( kdr -RS) and susceptible ( kdr -SS) mosquitoes taking higher blood volume than homozygote ( kdr -RR) resistant individuals [11]. In contrast, little is known on the impact of metabolic resistance as DNA-based markers were not previously available for this mechanism preventing to investigate its physiological impact on the blood feeding process in mosquitoes.…”

Influence of GST- and P450-based metabolic resistance to pyrethroids on blood feeding in the major African malaria vector Anopheles funestus

“…The volume of blood taken by a mosquito could be affected by a range of intrinsic (host immunity) and extrinsic factors including ambient temperatures, mosquito age, parity status, gonotrophic cycle, blood feeding history and infection status [10]. More recently, it was reported that exposure to pyrethroids could also significantly influence the process of taking a blood meal and the blood meal volume ingested by Kdr-resistant Anopheles gambiae females [11]. Pyrethroids (PY) are the insecticide class mostly used in the last two decades through ITNs and IRS strategies to control malaria transmission [12].…”