Armadilha BG-Malária para monitoramento de anofelinos neotropicais e afro-tropicais: otimização e avaliação da aplicabilidade como ferramenta complementar de controle da malária

Abstract

The BG-Malaria trap (BGM) was developed was conceived by adapting the BG-Sentinel trap (BGS), and it was demonstrated as efficient tool for sampling the main Brazilian malaria vector, Nyssorhincus darlingi, but it has not previously been tested for African malaria vectors. Thus, BGM was evaluated to collect African anophelines in experiments conducted in Tanzania, where it was compared to BGS and human landing catch (HLC) in field. In semi-field the comparison was done only against BGS with Anopheles arabiensis females from the Ifakara Health Institute colony. The An. arabiensis flight dynamics near both traps, BGM and BGS, was also evaluated in a video studio. In field, HLC caught more Anopheles gambiae s.l. than either trap (p <0.001), although BGM was more effective than BGS (p <0.001) and this result was also obtained in the semi-field with BGM catching twice as many mosquitoes as BGS (p <0.001). BGM caught more Anopheles funestus s.l., the dominant vector in southeastern Tanzania, than the other methods, including HLC, but there was no significant difference. BGM's superiority over BGS was also demonstrated in the filming tests, where more mosquitoes flew around BGM, more often and for longer. Subsequently, a comparison was made between BGMs baited with the attractants Ifakara Blend (IB), Mbita Blend (MB5) and CO2 (from sugarcane molasses-yeast fermentation). Field experiments were conducted in Tanzania and Brazil and the semi-field in Tanzania with An. Arabiensis females. In Brazil, the addition of CO2 increased the number of Ny. darlingi caught by IB and MB5 (p <0.05). In the comparison between IB, MB5 and CO2, there was no significant difference in the catches of An. arabiensis, An. gambiae s.l. and Ny. darlingi in semi-field, field in Tanzania and field in Brazil, respectively (p >0.05). In addition, In Brazil and Tanzania, BGMs were compared when baited with IB dispensed by different dispensers: (1) a new dispenser developed at UFMG, (2) BG-Cartridge (Biogents Company) and (3) nylon strips. In the field tests in Brazil and semi-field in Tanzania, there was no difference between treatments evaluated in the semi-field and field in Brazil (p >0.05), however, in the field in Tanzania, BG-Cartridge caught more An. gambiae s.l. than the other dispensers (p <0.001). BGM was also evaluated as a component of a push-pull system, comprised of a spatial repellent (the pyrethroid transfluthrin (0.25g/m2)) and the trap. Number of BGMs (1, 2 or 4) and their distance (5m, 15m or 30m) from semi-field trial houses were evaluated. The push-pull system offered greater protection against An. arabiensis bites than its components individually evaluated, but its effectiveness was attributed to the use of the repellent, differing only when compared with the traps alone (p <0.05). The best configuration of push–pull was comprised of the spatial repellent plus two traps, each at least 15m from houses. Therefore, the present work evaluated BGM in order to provide information that contributes to its incorporation in malaria vector monitoring and control programs in Brazil and worldwide.