Ivermectin-Based Toxic Sugar Baits Against Pyrethroid-Resistant Anopheles Vectors: A Critical Synthesis for Sub-Saharan Africa

Malaria control in sub-Saharan Africa remains heavily dependent on insecticide-treated nets and indoor residual surface treatments, yet pyrethroid resistance, outdoor biting and behavioural avoidance increasingly constrain the protection achievable with indoor interventions alone. Attractive toxic sugar baits exploit the obligate or recurrent sugar-feeding behaviour of adult mosquitoes and can deliver orally active compounds outside conventional contact-insecticide pathways. Ivermectin is a macrocyclic lactone that acts principally through invertebrate glutamate-gated chloride channels and is lethal to several Anopheles species after oral exposure. This critical narrative review evaluates whether ivermectin-based attractive toxic sugar baits constitute a credible complementary intervention for pyrethroid-resistant malaria vectors in sub-Saharan Africa. Literature was selected from accessible biomedical indexes, scholarly repositories, DOI metadata services and authoritative institutional sources, with emphasis on work available from 2008 to 23 May 2026 and inclusion of earlier foundational studies where necessary. Direct evidence remains limited. Laboratory and prototype studies show that ivermectin delivered in sucrose can kill susceptible and insecticide-resistant Anopheles, but efficacy varies with species, population, dose, feeding state and formulation. The wider attractive toxic sugar bait literature demonstrates that high feeding coverage can suppress vector populations and entomological transmission measures, while a recent cluster-randomised trial of a non-ivermectin product in Mali did not show overall additional protection against malaria under insecticide-treated-net coverage. Mechanistic independence from pyrethroids is therefore an advantage, not proof of field effectiveness or resistance-proof performance. Translation depends on achieving reliable feeding across heterogeneous vector populations, maintaining dose and palatability under tropical conditions, limiting non-target exposure, and embedding susceptibility surveillance within deployment. Ivermectin-based baits are best regarded as a targeted outdoor and peridomestic complement for settings with demonstrable sugar-bait uptake and residual transmission, rather than a replacement for established interventions. Carefully staged semi-field, village-randomised and epidemiological trials are required before public-health deployment can be justified.