Studies on the resting behaviour and host choice of Anopheles gambiae and An. arabiensis from Muleba, Tanzania

Abstract

The relative efficacy of a mechanical (Prokopack) collection method vs. manual aspiration in the collection of resting mosquitoes was evaluated in northern Tanzania before and after an intervention using indoor residual spraying and longlasting insecticide-treated nets. In smoke-free houses mosquitoes were collected from the roof and walls, but in smoky houses mosquitoes were found predominantly on the walls. Anopheles gambiae (Diptera: Culicidae) constituted 97.7% of the 312 An. gambiae complex specimens identified before but only 19.3% of the 183 identified after the intervention. A single sampling with the Prokopack collected a third of the available insects. Anopheles gambiae completed its gonotrophic development indoors, whereas Anopheles arabiensis did so outdoors. In both species gonotrophic development took 2 days. Most unfed resting An. arabiensis collected outdoors were virgins, whereas the majority of engorged insects were parous (with well-contracted sacs). Daily survival was estimated to be 80.0%. Only 9.4% of the engorged An. arabiensis collected outdoors and 47.1% of those collected indoors had fed on humans. Using the Prokopack sampler is more efficient than manual methods for the collection of resting mosquitoes. Malaria transmission may have been affected by a change in vector composition resulting from a change in feeding, rather than reduced survival. Monitoring the proportions of members of the An. gambiae complex may provide signals of an impending breakdown in control.

Estimating absolute indoor density of Aedes aegypti using removal sampling

“…This methodology has the potential to be expanded to other disease vectors readily collected using Prokopack aspirators such as endophilic Anopheles spp. [19–21] and Culex spp. [22].…”

“…Used primarily in research, adult aspiration provides a relatively unbiased measure of mosquito relative abundance (i.e. collecting both males and females as well as fed and unfed females) when conducted for ~10-minutes per house [19–22]. This rapid measure of relative density may be prone to collector variability, or to differential capture rate as a function of vector density or the size and complexity of premises.…”

Testing a pyriproxyfen auto-dissemination station attractive to gravid Anopheles gambiae sensu stricto for the development of a novel attract-release -and-kill strategy for malaria vector control

“…1) to simulate the natural indoor environment where female An. gambiae s.s. take a blood-meal and rest till they are gravid [41]. The hut had a door and two windows that were shut when the experiment was in progress.…”

Cadmium tolerance pathway in Anopheles gambiae senso stricto

“…Also, An. arabiensis is an opportunistic feeder that derives blood meals sources from a variety of vertebrate hosts and exhibits outdoor feeding and resting (Killeen et al, 2016;Charlwood et al, 2018). This behavior factors, together with the potential for HM selection for high insecticide tolerance, possess a significant threat and potential breakdown on vector control strategies that target adult mosquitoes using insecticides to control indoor resting and feeding mosquitoes.…”