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Entomological impact of mass administration of ivermectin and dihydroartemisinin-piperaquine in The Gambia: a cluster-randomized controlled trial

Soumare, Harouna M.; Dabira, Edgard Diniba; Camara, Muhammed M.; Jadama, Lamin; Gaye, Pa Modou; Kanteh, Sainey; Jawara, Ebrima A.; Njie, Amie Kolleh; Sanneh, Fatou; Ndiath, Mamadou Ousman; Lindsay, Steven W.; Conteh, Bakary; Ceesay, Sainey; Mohammed, Nuredin; Ooko, Michael; Bradley, John; Drakeley, Chris; Erhart, Annette; Bousema, Teun; D’Alessandro, Umberto

Entomological impact of mass administration of ivermectin and dihydroartemisinin-piperaquine in The Gambia: a cluster-randomized controlled trial Thumbnail


Harouna M. Soumare

Edgard Diniba Dabira

Muhammed M. Camara

Lamin Jadama

Pa Modou Gaye

Sainey Kanteh

Ebrima A. Jawara

Amie Kolleh Njie

Fatou Sanneh

Mamadou Ousman Ndiath

Bakary Conteh

Sainey Ceesay

Nuredin Mohammed

Michael Ooko

John Bradley

Chris Drakeley

Annette Erhart

Teun Bousema

Umberto D’Alessandro


Background Vector control interventions in sub-Saharan Africa rely on insecticide-treated nets and indoor residual spraying. Insecticide resistance, poor coverage of interventions, poor quality nets and changes in vector behavior threaten the effectiveness of these interventions and, consequently, alternative tools are needed. Mosquitoes die after feeding on humans or animals treated with ivermectin (IVM). Mass drug administration (MDA) with IVM could reduce vector survival and decrease malaria transmission. The entomological impact of MDA of combined IVM and dihydroartemisinin-piperaquine was assessed in a community-based, cluster-randomized trial. Methods A cluster-randomized trial was implemented in 2018 and 2019 in 32 villages in the Upper River Region, The Gambia. The with the inhabitants of 16 intervention villages eligible to receive three monthly rounds of MDA at the beginning of the malaria transmission season. Entomological surveillance with light traps and human landing catches (HLC) was carried out during a 7- to 14-day period after each round of MDA, and then monthly until the end of the year. The mosquitocidal effect of IVM was determined by direct membrane feeding assays. Results Of the 15,017 mosquitoes collected during the study period, 99.65% (n = 14,965) were Anopheles gambiae sensu lato (An. gambiae s.l.), comprising Anopheles arabiensis (56.2%), Anopheles coluzzii (24.5%), Anopheles gambiae sensu stricto (An. gembiae s.s.; 16.0%) and Anopheles funestus sensu lato (An. funestus s.l.; 0.35%). No effect of the intervention on vector parity was observed. Vector density determined on light trap collections was significantly lower in the intervention villages in 2019 (adjusted incidence rate ratio: 0.39; 95% confidence interval [CI]: 0.20, 0.74; P = 0.005) but not in 2018. However, vector density determined in HLC collections was similar in both the intervention and control villages. The entomological inoculation rate was significantly lower in the intervention villages than in the control villages (odds ratio: 0.36, 95% CI: 0.19, 0.70; P  = 0·003). Mosquito mortality was significantly higher when blood fed on IVM-treated individuals up to 21 days post-treatment, particularly in adults and individuals with a higher body mass index. Conclusion Mass drug administration with IVM decreased vector density and the entomological inoculation rate while the effect on vector parity was less clear. Survival of mosquitoes fed on blood collected from IVM-treated individuals was significantly lower than that in mosquitoes which fed on controls. The influence of host characteristics on mosquito survivorship indicated that dose optimization could improve IVM efficacy. Future detailed entomological evaluation trials in which IVM is administered as stand-alone intervention may elucidate the contribution of this drug to the observed reduction in transmission.


Soumare, H. M., Dabira, E. D., Camara, M. M., Jadama, L., Gaye, P. M., Kanteh, S., …D’Alessandro, U. (2022). Entomological impact of mass administration of ivermectin and dihydroartemisinin-piperaquine in The Gambia: a cluster-randomized controlled trial. Parasites and Vectors, 15(1),

Journal Article Type Article
Publication Date 2022
Deposit Date Apr 3, 2023
Publicly Available Date Apr 3, 2023
Journal Parasites & Vectors
Publisher BioMed Central
Peer Reviewed Peer Reviewed
Volume 15
Issue 1


Published Journal Article (920 Kb)

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