Differential Behavioral Responses of &lt;I&gt;Anopheles gambiae&lt;/I&gt; (Diptera: Culicidae) Modulate Mortality Caused by Pyrethroid-Treated Bednets

Siegert, P. Y.; Walker, Edward D.; Miller, James R.

doi:10.1603/029.102.0607

Cited by 56 publications

(59 citation statements)

References 96 publications

(118 reference statements)

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“…Similarly, An. gambiae exposed to LLINs seem to temporarily lose the ability to host-seek (29). This study did not test for such additional indirect impacts; however, preliminary data indicate a reduction in the feeding success of exposed IR mosquitoes.…”

Section: Discussionmentioning

confidence: 72%

Delayed mortality effects cut the malaria transmission potential of insecticide-resistant mosquitoes

Viana

Hughes

Matthiopoulos

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

102

121

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Malaria transmission has been substantially reduced across Africa through the distribution of long-lasting insecticidal nets (LLINs). However, the emergence of insecticide resistance within mosquito vectors risks jeopardizing the future efficacy of this control strategy. The severity of this threat is uncertain because the consequences of resistance for mosquito fitness are poorly understood: while resistant mosquitoes are no longer immediately killed upon contact with LLINs, their transmission potential may be curtailed because of longer-term fitness costs that persist beyond the first 24 h after exposure. Here, we used a Bayesian state-space model to quantify the immediate (within 24 h of exposure) and delayed (>24 h after exposure) impact of insecticides on daily survival and malaria transmission potential of moderately and highly resistant laboratory populations of the major African malaria vector Anopheles gambiae. Contact with LLINs reduced the immediate survival of moderately and highly resistant An. gambiae strains by 60–100% and 3–61%, respectively, and delayed mortality impacts occurring beyond the first 24 h after exposure further reduced their overall life spans by nearly one-half. In total, insecticide exposure was predicted to reduce the lifetime malaria transmission potential of insecticide-resistant vectors by two-thirds, with delayed effects accounting for at least one-half of this reduction. The existence of substantial, previously unreported, delayed mortality effects within highly resistant malaria vectors following exposure to insecticides does not diminish the threat of growing resistance, but posits an explanation for the apparent paradox of continued LLIN effectiveness in the presence of high insecticide resistance.

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Section: Discussionmentioning

confidence: 72%

Delayed mortality effects cut the malaria transmission potential of insecticide-resistant mosquitoes

Viana

Hughes

Matthiopoulos

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

102

121

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“…arabiensis . Siegert et al [29] pointed out the same difference in repellency between an Olyset® Net (containing 1000 mg of permethrin per square meter) and a PermaNet® (55 mg of deltamethrin per square meter). The authors reported that the Olyset® Net reduced the landing attempts of mosquitoes and elevated their flight frequency, while there was a higher incidence of mosquito landing attempts on the PermaNet® [28].…”

Section: Discussionmentioning

confidence: 98%

Insecticidal and repellent activities of pyrethroids to the three major pyrethroid-resistant malaria vectors in western Kenya

Kawada

Ohashi

Dida

et al. 2014

Parasites & Vectors

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BackgroundThe dramatic success of insecticide treated nets (ITNs) and long-lasting insecticidal nets (LLINs) in African countries has been countered by the rapid development of pyrethroid resistance in vector mosquitoes over the past decade. One advantage of the use of pyrethroids in ITNs is their excito-repellency. Use of the excito-repellency of pyrethroids might be biorational, since such repellency will not induce or delay the development of any physiological resistance. However, little is known about the relationship between the mode of insecticide resistance and excito-repellency in pyrethroid-resistant mosquitoes.MethodsDifferences in the reactions of 3 major malaria vectors in western Kenya to pyrethroids were compared in laboratory tests. Adult susceptibility tests were performed using World Health Organization (WHO) test tube kits for F1 progenies of field-collected An. gambiae s.s., An. arabiensis, and An. funestus s.s., and laboratory colonies of An. gambiae s.s. and An. arabiensis. The contact repellency to pyrethroids or permethrin-impregnated LLINs (Olyset® Nets) was evaluated with a simple choice test modified by WHO test tubes and with the test modified by the WHO cone bioassay test.ResultsField-collected An. gambiae s.s., An. arabiensis, and An. funestus s.s. showed high resistance to both permethrin and deltamethrin. The allelic frequency of the point mutation in the voltage-gated sodium channel (L1014S) in An. gambiae s.s. was 99.3–100%, while no point mutations were detected in the other 2 species. The frequency of takeoffs from the pyrethroid-treated surface and the flying times without contacting the surface increased significantly in pyrethroid-susceptible An. gambiae s.s. and An. arabiensis colonies and wild An. arabiensis and An. funestus s.s. colonies, while there was no significant increase in the frequency of takeoffs or flying time in the An. gambiae s.s. wild colony.ConclusionA different repellent reaction was observed in the field-collected An. gambiae s.s. than in An. arabiensis and An. funestus s.s. It might be that resistant mosquitoes governed by knockdown resistance (kdr) loose repellency to pyrethroids, whereas those lacking kdr maintain high repellency irrespective of their possessing metabolic resistance factors to pyrethroids. Further genetic evaluation is required for the demonstration of the above hypothesis.

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“…gambiae strains are exposed to insecticides, they are less likely to develop a malaria infection (16,17). Other research shows sublethal exposure to LLINs changes mosquito feeding behavior and responsiveness to host feeding cues (18). Lower parasite burdens and changes in feeding behavior could contribute to reduced transmission, even in the absence of mortality.…”

mentioning

confidence: 99%

The threat (or not) of insecticide resistance for malaria control

Thomas

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2016

Proc. Natl. Acad. Sci. U.S.A.

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Differential Behavioral Responses of <I>Anopheles gambiae</I> (Diptera: Culicidae) Modulate Mortality Caused by Pyrethroid-Treated Bednets

Cited by 56 publications

References 96 publications

Delayed mortality effects cut the malaria transmission potential of insecticide-resistant mosquitoes

Delayed mortality effects cut the malaria transmission potential of insecticide-resistant mosquitoes

Insecticidal and repellent activities of pyrethroids to the three major pyrethroid-resistant malaria vectors in western Kenya

The threat (or not) of insecticide resistance for malaria control

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