Grisales, Nelson, Lees, Rosemary S, Maas, James, Morgan, John C, Wangrawa, Dimitri W, Guelbeogo, Wamdaogo M, N'Fale, Sagnon, Lindsay, Steven W, McCall, Philip J 
ORCID: 0000-0002-0007-3985 and Ranson, Hilary
(2021)
Pyriproxyfen-treated bed nets reduce reproductive fitness and longevity of pyrethroid-resistant <i>Anopheles gambiae</i> under laboratory and field conditions.
MALARIA JOURNAL, 20 (1).
273-.
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Pyriproxyfen-treated bed nets reduce reproductive fitness and longevity of pyrethroid-resistant Anopheles gambiae under labo.pdf - Open Access published version Download (1MB) | Preview |
Abstract
<h4>Background</h4>The efficacy of insecticide-treated nets (ITNs) containing the insect growth regulator pyriproxyfen (PPF) and pyrethroid insecticides (PPF-ITNs) is being assessed in clinical trials to determine whether they provide greater protection from malaria than standard pyrethroid-treated ITNs in areas where mosquitoes are resistant to pyrethroids. Understanding the entomological mode of action of this new ITN class will aide interpretation of the results from these trials.<h4>Methods</h4>Anopheles gambiae sensu lato (s.l.) mosquitoes from a susceptible laboratory strain were exposed to PPF-treated netting 24 h, 6 h, and immediately prior to, or 24 h post blood feeding, and the impact on fecundity, fertility and longevity recorded. Pyrethroid-resistant populations were exposed to nets containing permethrin and PPF (PPF-ITNs) in cone bioassays and daily mortality recorded. Mosquitoes were also collected from inside houses pre- and post-distribution of PPF-ITNs in a clinical trial conduced in Burkina Faso; female An. gambiae s.l. were then assessed for fecundity and fertility.<h4>Results</h4>PPF exposure reduced the median adult lifespan of insecticide-susceptible mosquitoes by 4 to 5 days in all exposure times (p < 0.05) other than 6 h pre-blood meal and resulted in almost complete lifelong sterilization. The longevity of pyrethroid-resistant mosquitoes was also reduced by at least 5 days after exposure to PPF-ITNs compared to untreated nets, but was unaffected by exposure to standard pyrethroid only ITNs. A total of 386 blood-fed or gravid An. gambiae s.l. females were collected from five villages between 1 and 12 months before distribution of PPF-ITNs. Of these mosquitoes, 75% laid eggs and the remaining 25% appeared to have normal ovaries upon dissection. In contrast, only 8.6% of the 631 blood-fed or gravid An. gambiae s.l. collected post PPF-ITN distribution successfully oviposited; 276 (43.7%) did not oviposit but had apparently normal ovaries upon dissection, and 301 (47.7%) did not oviposit and had abnormal eggs upon dissection. Egg numbers were also significantly lower (average of 138/female prior distribution vs 85 post distribution, p < 0.05).<h4>Conclusion</h4>Exposure to a mixture of PPF and pyrethroids on netting shortens the lifespan of mosquitoes and reduces reproductive output. Sterilization of vectors lasted at least one year under operational conditions. These findings suggest a longer effective lifespan of PPF-pyrethroid nets than reported previously.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Pyriproxyfen (PPF), Anopheles gambiae, Insecticide-treated nets (ITNs), Juvenile hormone (JH), Olyset Duo (R), Pyrethroid-resistance |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 06 Jul 2023 13:45 |
| Last Modified: | 19 Oct 2023 09:04 |
| DOI: | 10.1186/s12936-021-03794-z |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3171499 |
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