Effect of Ivermectin® on survivorship and fertility of Anopheles arabiensis in Ethiopia: an in vitro study

• Published in: Malaria Journal
• Main Authors: Kasahun Eba, Tibebu Habtewold, Lechisa Asefa, Teshome Degefa, Delenasaw Yewhalaw, Luc Duchateau
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2023
• Subjects: Ivermectin; Mosquito mortality; An. arabiensis; Wild mosquitoes; Laboratory mosquitoes; Ethiopia; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic; Meier
• Online Access: https://doi.org/10.1186/s12936-023-04440-6; https://doaj.org/article/0522569b99274e04bf64e32eb18d910b

Abstract Background Innovative vector control tools are needed to counteract insecticide resistance and residual malaria transmission. One of such innovative methods is an ivermectin (IVM) treatment to reduce vector survival. In this study, a laboratory experiment was conducted to investigate the effect of ivermectin on survivorship, fertility and egg hatchability rate of Anopheles arabiensis in Ethiopia. Methods An in vitro experiment was conducted using 3–5 days old An. arabiensis adults from a colony maintained at insectary of Tropical and Infectious Diseases Research Center, Jimma University (laboratory population) and Anopheles mosquitoes reared from larvae collected from natural mosquito breeding sites (wild population). The mosquitoes were allowed to feed on cattle blood treated with different doses of ivermectin (0 ng/ml, 5 ng/ml, 10 ng/ml, 20 ng/ml, 40 ng/ml and 80 ng/ml). During each feeding experiment, the mosquitoes were held in cages and blood-fed using a Hemotek feeder. Mortality and egg production were then recorded daily for up to 9 days. Time to death was analysed by a Cox frailty model with replicate as frailty term and source of mosquito (wild versus laboratory), treatment type (ivermectin vs control) and their interaction as categorical fixed effects. Kaplan Meier curves were plotted separately for wild and laboratory populations for a visual interpretation of mosquito survival as a function of treatment. Results Both mosquito source and treatment had a significant effect on survival (P < 0.001), but their interaction was not significant (P = 0.197). Compared to the controls, the death hazard of An. arabiensis that fed on ivermectin-treated blood was 2.3, 3.5, 6.5, 11.5 and 17.9 times that of the control for the 5 ng/ml, 10 ng/ml, 20 ng/ml, 40 ng/ml, and 80 ng/ml dose, respectively. With respect to the number of hatched larvae, hatched pupae and emerged adults per fed mosquitoes, a significant difference was found between the control and the 5 ng/ml dose group (P < 0.001). The number of ...