Epopa, PS, Collins, CM, North, A, Millogo, AA, Benedict, MQ, Tripet, F and Diabate, A (2019) Seasonal malaria vector and transmission dynamics in western Burkina Faso. Malaria Journal, 18 (1). 113 -?.

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Abstract

BACKGROUND
In the context of widespread mosquito resistance to currently available pesticides, novel, precise genetic vector control methods aimed at population suppression or trait replacement are a potentially powerful approach that could complement existing malaria elimination interventions. Such methods require knowledge of vector population composition, dynamics, behaviour and role in transmission. Here were characterized these parameters in three representative villages, Bana, Pala and Souroukoudingan, of the Sudano-Sahelian belt of Burkina Faso, a region where bed net campaigns have recently intensified.

METHODS
From July 2012 to November 2015, adult mosquitoes were collected monthly using pyrethroid spray catches (PSC) and human landing catches (HLC) in each village. Larval habitat prospections assessed breeding sites abundance at each site. Mosquitoes collected by PSC were identified morphologically, and then by molecular technique to species where required, to reveal the seasonal dynamics of local vectors. Monthly entomological inoculation rates (EIR) that reflect malaria transmission dynamics were estimated by combining the HLC data with mosquito sporozoite infection rates (SIR) identified through ELISA-CSP. Finally, population and EIR fluctuations were fit to locally-collected rainfall data to highlight the strong seasonal determinants of mosquito abundance and malaria transmission in this region.

RESULTS
The principal malaria vectors found were in the Anopheles gambiae complex. Mosquito abundance peaked during the rainy season, but there was variation in vector species composition between villages. Mean survey HLC and SIR were similar across villages and ranged from 18 to 48 mosquitoes/person/night and from 3.1 to 6.6% prevalence. The resulting monthly EIRs were extremely high during the rainy season (0.91-2.35 infectious bites/person/day) but decreased substantially in the dry season (0.03-0.22). Vector and malaria transmission dynamics generally tracked seasonal rainfall variations, and the highest mosquito abundances and EIRs occurred in the rainy season. However, despite low residual mosquito populations, mosquitoes infected with malaria parasites remained present in the dry season.

CONCLUSION
These results highlight the important vector control challenge facing countries with high EIR despite the recent campaigns of bed net distribution. As demonstrated in these villages, malaria transmission is sustained for large parts of the year by a very high vector abundance and high sporozoite prevalence, resulting in seasonal patterns of hyper and hypo-endemicity. There is, therefore, an urgent need for additional vector control tools that can target endo and exophillic mosquito populations.

Item Type: Article
Additional Information: This is the final published version of the article (version of record). It first appeared online via BioMed Central at https://doi.org/10.1186/s12936-019-2747-5 - please refer to any applicable terms of use of the publisher.
Uncontrolled Keywords: Anopheles gambiae s.l., Entomological Inoculation Rate, Genetic control, Seasonal dynamic, Vector control
Subjects: R Medicine > R Medicine (General)
Divisions: Faculty of Natural Sciences > School of Life Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 29 Apr 2019 09:48
Last Modified: 29 Apr 2019 09:50
URI: http://eprints.keele.ac.uk/id/eprint/6229

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