Author:
Tchouakui Magellan,Assatse Tatiane,Tazokong Hervé R.,Oruni Ambrose,Menze Benjamin D.,Nguiffo-Nguete Daniel,Mugenzi Leon M. J.,Kayondo Jonathan,Watsenga Francis,Mzilahowa Themba,Osae Michael,Wondji Charles S.
Abstract
AbstractNew insecticides have recently been produced to help control pyrethroid-resistant malaria vectors including the pyrrole, chlorfenapyr. Monitoring the susceptibility of mosquito populations against this new product and potential cross-resistance with current insecticides is vital for better resistance management. In this study, we assessed the resistance status of the major malaria vectors Anopheles gambiae and Anopheles funestus to chlorfenapyr across Africa and explored potential cross-resistance with known pyrethroid resistance markers. Efficacy of chlorfenapyr 100 µg/ml against An. gambiae and An. funestus from five Cameroonian locations, the Democratic Republic of Congo, Ghana, Uganda, and Malawi was assessed using CDC bottle assays. Synergist assays were performed with PBO (4%), DEM (8%) and DEF (0.25%) and several pyrethroid-resistant markers were genotyped in both species to assess potential cross-resistance between pyrethroids and chlorfenapyr. Resistance to chlorfenapyr was detected in An. gambiae populations from DRC (Kinshasa) (mortality rate: 64.3 ± 7.1%) Ghana (Obuasi) (65.9 ± 7.4%), Cameroon (Mangoum; 75.2 ± 7.7% and Nkolondom; 86.1 ± 7.4). In contrast, all An. funestus populations were fully susceptible. A negative association was observed between the L1014F-kdr mutation and chlorfenapyr resistance with a greater frequency of homozygote resistant mosquitoes among the dead mosquitoes after exposure compared to alive (OR 0.5; P = 0.02) whereas no association was found between GSTe2 (I114T in An. gambiae; L119F in An. funestus) and resistance to chlorfenapyr. A significant increase of mortality to chlorfenapyr 10 µg/ml was observed in An. funestus after to PBO, DEM and DEF whereas a trend for a decreased mortality was observed in An. gambiae after PBO pre-exposure. This study reveals a greater risk of chlorfenapyr resistance in An. gambiae populations than in An. funestus. However, the higher susceptibility in kdr-resistant mosquitoes points to higher efficacy of chlorfenapyr against the widespread kdr-based pyrethroid resistance.
Funder
Wellcome Trust
Bill and Melinda Gates Foundation
Publisher
Springer Science and Business Media LLC
Reference34 articles.
1. Bhatt, S. et al. The effect of malaria control on Plasmodium falciparum in Africa between 2000 and 2015. Nature 526, 207–211 (2015).
2. Hemingway, J. et al. Country-level operational implementation of the Global Plan for Insecticide Resistance Management. Proc. Natl. Acad. Sci. USA 110, 9397–9402. https://doi.org/10.1073/pnas.1307656110 (2013).
3. WHO. List of WHO Prequalified Vector Control Products (World Health Organization, 2019).
4. Ngufor, C. et al. Chlorfenapyr (a pyrrole insecticide) applied alone or as a mixture with alpha-cypermethrin for indoor residual spraying against pyrethroid resistant Anopheles gambiae sl: An experimental hut study in Cove. Benin. PLoS One 11, e0162210 (2016).
5. Black, B. C., Hollingworth, R. M., Ahammadsahib, K. I., Kukel, C. D. & Donovan, S. Insecticidal action and mitochondrial uncoupling activity of AC-303,630 and related halogenated pyrroles. Pestic. Biochem. Physiol. 50, 115–128 (1994).