Susceptibility status of Anopheles gambiae s.l. to insecticides used for malaria control in Kinshasa, Democratic Republic of the Congo

Abstract

Contexte et objectif. Malgré plusieurs années de lutte, le paludisme demeure toujours la première cause de mortalité infantile sous les tropiques. Actuellement, la stratégie de contrôle vise des actions simultanées contre l’agent causal et le vecteur du paludisme. L’objectif de la présente étude était de décrire la distribution de la sensibilité d'Anopheles gambiae sl aux insecticides à travers la ville de Kinshasa. Méthodes. Des larves d'anophèles ont été collectées, à travers sept sites de Kinshasa, pendant la période allant de septembre 2017 à mai 2018. Des bioessais standard de l'OMS ont été utilisés pour mesurer la sensibilité d'Anopheles gambiae s.l. aux insecticides. La distribution des espèces et le profil de résistance ont été évalués en recourant aux tests diagnostiques moléculaires. Résultats. Deux espèces du complexe gambiae ont été identifiées : An. gambiae (98,3 %) et An. coluzzii (1,7 %). Une variabilité du statut de résistance à la deltaméthrine par site a été observée. Cependant, une restauration de la sensibilité a été notée après une pré-exposition au butoxyde de pipéronyle (PBO) dans tous les sites présentant une résistance à la deltaméthrine. Conclusion. La présente étude a démontré qu’An. gambiae s.l. était résistant à la perméthrine dans tous les sites retenus. Cependant, la résistance à la deltaméthrine était variable. Le profil de résistance indique que les moustiquaires deltaméthrine+PBO devraient être envisagées pour la lutte anti vectorielle.
 Context and objective. Despite many years of control, malaria remains the leading cause of child mortality in the tropics. Currently, the control strategy aims at simultaneous actions against the causal agent and the vector of malaria. This study aimed to describe the distribution of the susceptibility of Anopheles gambiae sl to insecticides across the city of Kinshasa. Methods. Anopheles larvae were collected from seven sites in Kinshasa during the period from September 2017 to May 2018. Standard WHO bioassays were used to determine the sensitivity of Anopheles gambiae s.l. to insecticides. The species distribution and the resistance profile were evaluated by polymerase chain reaction. Results. Two species of the gambiae complex were identified: An. gambiae (98.3 %) and An. coluzzii (1.7 %). Variability of deltamethrin resistance status by site was observed; however, a restoration of susceptibility was noted after pre-exposure to piperonyl butoxide (PBO) in all sites with deltamethrin resistance. Conclusion. The present study showed that An. gambiae s.l. was resistant to permethrin in all the selected sites. However, resistance to deltamethrin was variable. The resistance profile indicates that deltamethrin+PBO nets should be considered for vector control.

Species Composition and Distribution of Anopheles gambiae Complex Circulating in Kinshasa

“…Compared to the other species that did not show large fluctuations, the frequencies of Anopheles gambiae complex increased rapidly during the rainy season, with maximum densities recorded in the months of November and April, and then decreased steadily during the dry season, with lower densities captured in the months of June and July. The fluctuation in rainfall between the dry and wet seasons in Kinshasa with the presence of temporary puddles (shallow, sunny pools) widely distributed in Kinshasa during the rainy season [20]. correlated with high larval densities of Anopheles gambiae complex [36][37].…”

“…gambiae complex circulating in Kinshasa. These two species were previously identified by Riveron in and Zanga (18,20). The approaches of these two studies were limited to very specific areas of Kinshasa.…”

“…In the Democratic Republic of Congo (DRC), the Anopheles gambiae complex plays a major role in malaria transmission [17]. Most publications report a clear predominance of the former ss form, currently recognised as Anopheles gambiae [18][19][20][21]. Anopheles gambiae is widely distributed in Kinshasa [18,20], however the Bobanga study, conducted in 2013, notes the presence of the sympatric species Anopheles coluzzii, in the Mont Amba district of Kinshasa [22].…”

“…The IPT ensures data validation through its network. Metadata fields are available at the dataset page in GBIF [42].…”

“…The data supporting this article are published through the Integrated Publishing Toolkit of GBIF [41] and are available under a CC0 waiver from GBIF [42].…”