Anopheline and human drivers of malaria risk in northern coastal, Ecuador: a pilot study
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Malaria Journal Open Access
RESEARCH
Anopheline and human drivers of malaria risk in northern coastal, Ecuador: a pilot study James A. Martin1, Allison L. Hendershot1, Iván Alejandro Saá Portilla2, Daniel J. English1, Madeline Woodruff1, Claudia A. Vera‑Arias1,2, Bibiana E. Salazar‑Costa2, Juan José Bustillos2, Fabián E. Saénz2, Sofía Ocaña‑Mayorga2*† , Cristian Koepfli1 and Neil F. Lobo1†
Abstract Background: Understanding local anopheline vector species and their bionomic traits, as well as related human fac‑ tors, can help combat gaps in protection. Methods: In San José de Chamanga, Esmeraldas, at the Ecuadorian Pacific coast, anopheline mosquitoes were sam‑ pled by both human landing collections (HLCs) and indoor-resting aspirations (IAs) and identified using both mor‑ phological and molecular methods. Human behaviour observations (HBOs) (including temporal location and bed net use) were documented during HLCs as well as through community surveys to determine exposure to mosquito bites. A cross-sectional evaluation of Plasmodium falciparum and Plasmodium vivax infections was conducted alongside a malaria questionnaire. Results: Among 222 anopheline specimens captured, based on molecular analysis, 218 were Nyssorhynchus albimanus, 3 Anopheles calderoni (n = 3), and one remains unidentified. Anopheline mean human-biting rate (HBR) outdoors was (13.69), and indoors (3.38) (p = 0.006). No anophelines were documented resting on walls during IAs. HBO-adjusted human landing rates suggested that the highest risk of being bitten was outdoors between 18.00 and 20.00 h. Human behaviour-adjusted biting rates suggest that overall, long-lasting insecticidal bed nets (LLINs) only protected against 13.2% of exposure to bites, with 86.8% of exposure during the night spent outside of bed net pro‑ tection. The malaria survey found 2/398 individuals positive for asymptomatic P. falciparum infections. The question‑ naire reported high (73.4%) bed net use, with low knowledge of malaria. Conclusion: The exophagic feeding of anopheline vectors in San Jose de Chamanga, when analysed in conjunction with human behaviour, indicates a clear gap in protection even with high LLIN coverage. The lack of indoor-resting anophelines suggests that indoor residual spraying (IRS) may have limited effect. The presence of asymptomatic infec‑ tions implies the presence of a human reservoir that may maintain transmission. Keywords: Nyssorhynchus albimanus, Anopheles calderoni, Plasmodium falciparum, Bionomics, Malaria, Long-lasting insecticide-treated nets (LLINs), Indoor residual spraying (IRS), Human behaviour, Ecuador
*Correspondence: [email protected] † Sofía Ocaña-Mayorga and Neil F. Lobo contributed equally to this work 2 Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530 Nayón, Ecuador Full list of author information is available at the end of the article
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