Anophelesbionomics, insecticide resistance mechanisms, and malaria transmission in the Korhogo area, northern Côte d’Ivoire: a pre-intervention study

Abstract

A better understanding of malaria transmission at a local scale is essential for developing and implementing effective control strategies. In the framework of a randomized controlled trial (RCT), we aimed to provide an updated description of malaria transmission in the Korhogo area, northern Côte d’Ivoire, and to obtain baseline data for the trial. We performed human landing collections (HLCs) in 26 villages in the Korhogo area during the rainy season (September–October 2016, April–May 2017) and the dry season (November–December 2016, February–March 2017). We used PCR techniques to ascertain the species of the Anopheles gambiae complex, Plasmodium falciparum sporozoite infection, and insecticide resistance mechanisms in a subset of Anopheles vectors. Anopheles gambiae s.l. was the predominant malaria vector in the Korhogo area. Overall, more vectors were collected outdoors than indoors (p < 0.001). Of the 774 An. gambiae s.l. tested in the laboratory, 89.65% were An. gambiae s.s. and 10.35% were An. coluzzii. The frequencies of the kdr allele were very high in An. gambiae s.s. but the ace-1 allele was found at moderate frequencies. An unprotected individual living in the Korhogo area received an average of 9.04, 0.63, 0.06 and 0.12 infected bites per night in September–October, November–December, February–March, and April–May, respectively. These results demonstrate that the intensity of malaria transmission is extremely high in the Korhogo area, especially during the rainy season. Malaria control in highly endemic areas such as Korhogo needs to be strengthened with complementary tools in order to reduce the burden of the disease.

Evaluation of the interaction between insecticide resistance-associated genes and malaria transmission in Anopheles gambiae sensu lato in central Côte d’Ivoire

“…gambiae than in An. coluzzii , which was in agreement with observations of Koukpo et al [ 36 ] in Benin and Zogo et al [ 37 ] in Côte d’Ivoire. There was a 59 times greater probability of encountering the Kdr L1014F resistance allele in An.…”

Interaction Between Insecticide Resistance-Associated Genes and Malaria Transmission in Anopheles Gambiae S. L. During a Cluster-Randomized Controlled Trial of A “lethal House Lure” in Central Côte D’ivoire

“…gambiae than in An. coluzzii, which was in agreement with observations of Koukpo et al[36] in Benin and by Zogo et al [37] in Côte d'Ivoire. There were 59 times greater probability of encountering Kdr L1014F resistance allele of An.…”

Entomological Indicators of Malaria Transmission Prior to a Cluster Randomised Controlled Trial of a “Lethal House Lure” Intervention in Central Côte D’Ivoire

“…This aligns with previous studies conducted in the same area, and elsewhere in Côte d'Ivoire, which reported the predominance of An gambiae s.l. among local malaria vectors [22,23].…”

“…coluzzii found in high proportion (85.90%) was consistent with previous ndings in the area of Bouaké [21,24,25] but contrasts with other studies in the northern savannah of the country, whereAn. gambiae was more prevalent [22,26]. The difference observed is likely due to variations in mosquito larval habitats; An.…”