Technical Workflow Development for Integrating Drone Surveys and Entomological Sampling to Characterise Aquatic Larval Habitats of Anopheles funestus in Agricultural Landscapes in Côte d’Ivoire

Land-use practices such as agriculture can impact mosquito vector breeding ecology, resulting in changes in disease transmission. The typical breeding habitats of Africa’s second most important malaria vector Anopheles funestus are large, semipermanent water bodies, which make them potential candidates for targeted larval source management. This is a technical workflow for the integration of drone surveys and mosquito larval sampling, designed for a case study aiming to characterise An. funestus breeding sites near two villages in an agricultural setting in Côte d’Ivoire. Using satellite remote sensing data, we developed an environmentally and spatially representative sampling frame and conducted paired mosquito larvae and drone mapping surveys from June to August 2021. To categorise the drone imagery, we also developed a land cover classification scheme with classes relative to An. funestus breeding ecology. We sampled 189 potential breeding habitats, of which 119 (63%) were positive for the Anopheles genus and nine (4.8%) were positive for An. funestus. We mapped 30.42 km2 of the region of interest including all water bodies which were sampled for larvae. These data can be used to inform targeted vector control efforts, although its generalisability over a large region is limited by the fine-scale nature of this study area. This paper develops protocols for integrating drone surveys and statistically rigorous entomological sampling, which can be adjusted to collect data on vector breeding habitats in other ecological contexts. Further research using data collected in this study can enable the development of deep-learning algorithms for identifying An. funestus breeding habitats across rural agricultural landscapes in Côte d’Ivoire and the analysis of risk factors for these sites.

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Bushmeat hunting around a remnant coastal rainforest in Côte d'Ivoire

Oryx ◽

10.1017/s0030605315001453 ◽

2016 ◽

Vol 51 (3) ◽

pp. 418-427 ◽

Cited By ~ 5

Author(s):

S. Gonedelé Bi ◽

Inza Koné ◽

J.C.K. Béné ◽

E.A. Bitty ◽

K.A. Yao ◽

...

Keyword(s):

Cote D'ivoire ◽

Côte D’Ivoire ◽

Mammalian Species ◽

Agricultural Landscapes ◽

Political Crisis ◽

Total Biomass ◽

Annual Income ◽

Cote D’Ivoire ◽

Côte D'ivoire ◽

Bushmeat Trade

AbstractFor most Ivorian regions quantitative data on the exploitation of bushmeat by local communities are scarce. We studied hunting patterns around Dassioko Sud Forest Reserve, a remnant coastal forest in south-eastern Côte d'Ivoire, through a 6-month survey of nine restaurants, in three villages surrounding the Reserve. We collected quantitative and qualitative data on the bushmeat brought to restaurants, as well as the final price for which it was sold. We calculated mean prices over the study period and extrapolated to the whole year. A total of 376 mammals (98%) and eight reptiles (2%) were sold in the restaurants surveyed. Rodents and small antelopes represented 74% of the mammals sold, probably reflecting the fact that reproductive strategists persist more successfully in heavily hunted and/or agricultural landscapes, such as the area around the Reserve. Our conservative estimate of the total biomass of bushmeat harvested annually around the Reserve is c. 40,428.03 kg (c. 11,886 animals), with a monetary value of c. FCFA 47,728,516 (c. USD 93,485.75 ), yielding an annual income of c. USD10,387.31 per person, which exceeds the mean annual income of cocoa farmers (FCFA 466,032/USD 932) more than tenfold. Although the sustainability of the bushmeat trade in the surveyed area remains unknown, we showed that hunters predominantly used cable snares, the Reserve was significantly affected by hunting activities (c. 53% of the bushmeat originated there), and larger mammalian species had been extirpated. A lack of effective protection exposes the Reserve to multiple illegal activities, including hunting, a situation exacerbated by the political crisis in 2010.

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Vectorial Transmission of Malaria in Major Districts of Côte d’Ivoire

Journal of Medical Entomology ◽

10.1093/jme/tjz207 ◽

2019 ◽

Vol 57 (3) ◽

pp. 908-914

Author(s):

Konan F Assouho ◽

Akré M Adja ◽

Négnorogo Guindo-Coulibaly ◽

Emmanuel Tia ◽

Affoué M N Kouadio ◽

...

Keyword(s):

Malaria Transmission ◽

Mass Distribution ◽

Cote D'ivoire ◽

Rural Areas ◽

Urban Areas ◽

Côte D’Ivoire ◽

Anopheles Funestus ◽

Malaria Vectors ◽

Cote D’Ivoire ◽

Côte D'ivoire

Abstract To better understand the influence of periodic mass distribution of Long-Lasting Insecticidal Nets (LLINs) on malaria transmission, a 1-yr entomological survey was conducted in three major districts of Côte d’Ivoire. Mosquitoes were sampled by Human Landing Catches (HLC) in urban and rural areas of San Pedro and Abidjan (coastal), and in Yamoussoukro (central). Mosquitoes were identified morphologically and by molecular methods. The Plasmodium falciparum circumsporozoite (CSP) indices were measured by ELISA, and the Entomological Inoculation Rates (EIR) were calculated for each species and area. Anopheles gambiae s.l. Giles (Diptera: Culicidae) and Anopheles nili Theobald (Diptera: Culicidae) were identified in coastal districts, while An. gambiae s.l. and Anopheles funestus Giles (Diptera: Culicidae) were reported in the central district. In urban areas, malaria vectors showed a low aggressiveness (<10 bites per person per night), except in Yamoussoukro, where up to 18.9 b/p/n were recorded. The annual EIR was higher in the central urban area (138.7 infected bites per person per year) than in coastal ones (10–62 ib/p/n). In rural areas, malaria vectors were highly aggressive with an average 13 b/p/n for An. gambiae s.l, 21.2 b/p/n for An. nili and 12 b/p/n for An. funestus. The annual EIR ranged between 94.9 and 193.4 infected bites per person per year. This work indicates that, despite repeated mass distribution of LLINs, malaria transmission remains high and heterogeneous across Côte d’Ivoire. Malaria transmission was lower in coastal urban areas than in the central one, and remains high rural areas where two additional Anopheles vectors are involved in malaria transmission.

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Entomological Indicators of Malaria Transmission Prior to a Cluster Randomised Controlled Trial of a “Lethal House Lure” Intervention in Central Côte D’Ivoire

10.21203/rs.3.rs-1146656/v1 ◽

2021 ◽

Author(s):

Rosine Zlanneu Wolie ◽

Alphonsine A. Koffi ◽

Lesley Ayuk-Taylor ◽

Ludovic P. Ahoua Alou ◽

Eleanore D. Sternberg ◽

...

Keyword(s):

Anopheles Gambiae ◽

Malaria Transmission ◽

Cote D'ivoire ◽

Côte D’Ivoire ◽

Controlled Trial ◽

Anopheles Funestus ◽

Malaria Vectors ◽

Cote D’Ivoire ◽

Côte D'ivoire ◽

Indoor And Outdoor

Abstract Background: A study was conducted prior to implementing a cluster randomised controlled trial (CRT) of a lethal house lure strategy in central Côte d’Ivoire and aimed to provide baseline information on malaria vectors in 40 village clusters. Methods: Human landing catches (HLC) was performed between November-December 2016, capturing mosquitoes indoor and outdoor between 18.00-08.00. Mosquitoes were processed for entomological indicators of malaria transmission (human biting rates, parity rates, sporozoite infection rates and the entomological inoculation rates (EIR)). Species composition and allelic frequencies of Kdr-w and Ace-1R mutations were also investigated within the Anopheles gambiae complex. Results: Overall, 15,632 mosquitoes were captured. Anopheles gambiae s.l. and Anopheles funestus were the two malaria vectors found during the survey period, with predominance for Anopheles gambiae s.l. (66.2%) compared to Anopheles funestus (10.3%). The mean biting rate for An. gambiae s.l. was almost 5 times higher than that for An. funestus s.l.(19.8 bites per person per night for An. gambiae s. l. vs 4.3 bites per person per night for An. funestus s. l.) and this was evident indoor and outdoor. An. funestus was more competent to transmit malaria parasites in the study area, despite relatively lower number tested for sporozoite index (1.6% (1,373) for An. gambiae vs 4.7 % (722) for An. funestus s.l.). There was no significant difference between the proportion infected outdoor and indoor for An. gambiae s.l. (1.6% vs 1.5%; OR=1.11[0.65-1.9]; P=0.676), but for An. funestus, more mosquitoes were infected outdoor (6.4%) than indoor (3.5%) (OR=1.86 [1.07-3.23]; P=0.0249). The majority of both infected vectors with malaria parasites harboured P. falciparum (90.6% for An. gambiae s. l. and 97, 8% for An. funestus s. l.). The EIR for both vectors (0.43 infected bites per night) were similar and there were no significant differences for transmission occurring outdoor and indoor for both species. Of the An. gambiae s.l. analysed, only An. gambiae (14.1%) and An. coluzzii (85.9%) were found. The allelic frequencies of Kdr and Ace-1R were higher in An. gambiae (0.97 for Kdr and 0.19 for Ace-1R) than in An. coluzzii (0.86 for Kdr and 0.10 for Ace-1R) (P<0.001).Conclusion: Despite universal coverage of long-lasting insecticidal nets (LLINs) in the area, there was an abundance of malaria vectors in the study in area in central Côte d’Ivoire, specifically highly resistant An. gambiae s.l. as well as An. funestus s.l.. The malaria sporozoite rate was higher in An. funestus s.l than An. gambiae s.l.. but EIR rates in these two species were similarly high, both indoor and outdoor. Novel tools or strategies are urgently needed to further reduce malaria transmission in this area.

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