Seasonal dynamics, resting behaviour and insecticide susceptibility of Anopheles mosquitoes across two differentially malaria-endemic regions in Ethiopia

Delelegn Woyessa ^1,2,3, Delenasaw Yewhalaw ^2,3

⁰Department of Biology, College of Natural Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia.

Current Research in Parasitology & Vector-Borne Diseases +

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December 3, 2024

View abstract on PubMed

Summary

This study in Ethiopia monitored Anopheles mosquito populations and insecticide resistance for 17 months. Findings highlight seasonal density variations and resistance to common insecticides, crucial for malaria control planning.

Area Of Science

Medical entomology
Malariology
Vector-borne disease epidemiology

Background

Understanding Anopheles mosquito bionomics, species composition, seasonal dynamics, and insecticide susceptibility is vital for malaria transmission assessment and control.
Effective vector control strategies depend on accurate eco-epidemiological data.

Purpose Of The Study

To investigate the species composition, seasonal abundance, and insecticide susceptibility of Anopheles mosquitoes in Lare District, Ethiopia.
To inform malaria vector control strategies through detailed bionomic data.

Main Methods

Adult Anopheles mosquitoes were collected over 17 months (June 2018-September 2020) using CDC light traps and human landing catches.
Larval and pupal collections were reared to adulthood. Insecticide susceptibility bioassays were performed using WHO guidelines.
Plasmodium spp. infection was detected using TaqMan qPCR.

Main Results

Anopheles coustani (46.20%) was the most prevalent species, followed by An. pharoensis (27.89%), An. gambiae (s.l.) (16.04%), and An. funestus (9.88%).
Mosquito densities peaked from June-November, with An. funestus showing higher density from November-January.
Resistance to DDT, deltamethrin, permethrin, and malathion was observed in An. pharoensis and An. gambiae (s.l.). An. coustani showed resistance to DDT and deltamethrin.
No Plasmodium spp. infections were found in An. coustani or An. pharoensis.

Conclusions

Seasonal variations in Anopheles mosquito density, particularly the dry-season presence of An. funestus, necessitate ongoing monitoring.
Widespread insecticide resistance in key malaria vectors, coupled with outdoor biting behavior, requires adaptive and integrated vector management approaches.
Regular monitoring and targeted interventions are crucial, considering the behavioral dynamics and resistance profiles of Anopheles species across seasons.

Keywords:

Anopheles Bionomics Ethiopia Insecticide resistance Mosquitoes Secondary vectors