Evaluation of MTego and BG-Sentinel traps for malaria and arbovirus vector surveillance in Cabo Verde

Abstract

Arboviral outbreaks are rising across Africa, a region that continues to face a substantial malaria burden. Cabo Verde remains vulnerable to the emergence and re-emergence of mosquito-borne diseases, including dengue, Zika, and malaria. In January 2024, the World Health Organization certified the country as malaria-free; however, the risk of reintroduction persists. Maintaining malaria-free status requires continuous robust epidemiological and entomological surveillance to prevent local transmission. Innovative vector monitoring and control tools that deliver accurate infestation data are essential in this context. We evaluated the performance of the MTego trap against the BGS traps routinely used in Cabo Verde applying a 4x4 Latin square design with four configurations: 1) BGS with BG Lure; 2) BGS with BG Lure plus CO 2 ; 3) MTego traps with Clay Balls plus PM6 odour bait; and 4) MTego traps with Clay Balls, PM6 bait plus CO 2 . Sampling was conducted in Praia, before and after the 2023 rainy season. Trap effectiveness was assessed using negative binomial regression models. Across all configurations, 2,673 mosquitoes were collected. Mean nightly catches were highest for BGS traps baited with CO 2 : 20.4 (95% CI: 15.4-25.4), and lowest for MTego traps: 13.7 (95% CI: 10.0-17.5). Comparative analysis showed that MTego traps outperformed BGS traps in capturing Anopheles arabiensis , with CO 2 -supplemented MTego trap being the most effective configuration. BGS traps performed best for Aedes aegypti and Culex pipiens sensu lato. Species-specific behavioural patterns were observed, with higher nigh-time catches of Cx pipiens s.l. and An. arabiensis , alongside differences in gonotrophic state. This study highlights the superior performance of MTego traps for malaria surveillance in Cabo Verde.