Pyrethroid and Etofenprox Resistance in <i>Anopheles gambiae</i> and <i>Anopheles coluzzii</i> from Vegetable Farms in Yaoundé, Cameroon: Dynamics, Intensity and Molecular Basis
Michael Piameu,
Philippe Nwane,
Wilson Toussile,
Konstantinos Mavridis,
Nadja Christina Wipf,
Paraudie France Kouadio,
Lili Ranaise Mbakop,
Stanislas Mandeng,
Wolfgang Eyisap Ekoko,
Jean Claude Toto,
Kelly Lionelle Ngaffo,
Petronile Klorane Ngo Etounde,
Arthur Titcho Ngantchou,
Mouhamadou Chouaibou,
Pie Müller,
Parfait Awono-Ambene,
John Vontas,
Josiane Etang
Affiliations
Michael Piameu
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
Philippe Nwane
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
Wilson Toussile
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
Konstantinos Mavridis
Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece
Nadja Christina Wipf
Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
Paraudie France Kouadio
Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, P.O. Box 1303, Abidjan 1303, Cote d’Ivoire
Lili Ranaise Mbakop
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
Stanislas Mandeng
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
Wolfgang Eyisap Ekoko
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
Jean Claude Toto
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
Kelly Lionelle Ngaffo
Institut de Recherche en Sciences de la Santé (IRSS), Centre d’excellence Africain en Innovations Biotechnologiques pour l’élimination des Maladies à Transmission Vectorielle (CEA/ITECH-MTV), Université Nazi Boni, P.O. Box 545, Bobo-Dioulasso 22620, Burkina Faso
Petronile Klorane Ngo Etounde
Ecole des Sciences de la Santé, Université Catholique d’Afrique Centrale, P.O. Box 1110, Yaoundé 999108, Cameroon
Arthur Titcho Ngantchou
Ecole des Sciences de la Santé, Université Catholique d’Afrique Centrale, P.O. Box 1110, Yaoundé 999108, Cameroon
Mouhamadou Chouaibou
Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, P.O. Box 1303, Abidjan 1303, Cote d’Ivoire
Pie Müller
Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
Parfait Awono-Ambene
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
John Vontas
Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece
Josiane Etang
Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon
Previous studies have indicated widespread insecticide resistance in malaria vector populations from Cameroon. However, the intensity of this resistance and underlying mechanisms are poorly known. Therefore, we conducted three cross-sectional resistance surveys between April 2018 and October 2019, using the revised World Health Organization protocol, which includes resistance incidences and intensity assessments. Field-collected Anopheles gambiae s.l. populations from Nkolondom, Nkolbisson and Ekié vegetable farms in the city of Yaoundé were tested with deltamethrin, permethrin, alpha-cypermethrin and etofenprox, using 1× insecticide diagnostic concentrations for resistance incidence, then 5× and 10× concentrations for resistance intensity. Subsamples were analyzed for species identification and the detection of resistance-associated molecular markers using TaqMan® qPCR assays. In Nkolbisson, both An. coluzzii (96%) and An. gambiae s.s. (4%) were found together, whereas only An. gambiae s.s. was present in Nkolondom, and only An. coluzzii was present in Ekié. All three populations were resistant to the four insecticides (kdr L995F, L995S, and N1570Y, and the Ace-1 G280S-resistant alleles were found in An. gambiae from Nkolondom, at 73%, 1%, 16% and 13% frequencies, respectively, whereas only the kdr L995F was found in An. gambiae s.s. from Nkolbisson at a 50% frequency. In An. coluzzii from Nkolbisson and Ekié, we detected only the kdr L995F allele at 65% and 60% frequencies, respectively. Furthermore, expression levels of Cyp6m2, Cyp9k1, and Gste2 metabolic genes were highly upregulated (over fivefold) in Nkolondom and Nkolbisson. Pyrethroid and etofenprox-based vector control interventions may be jeopardized in the prospected areas, due to high resistance intensity, with multiple mechanisms in An. gambiae s.s. and An. coluzzii.
