Insights gained from conducting a randomised controlled trial on Ivermectin-Albendazole against Trichuris trichiura in Côte d'Ivoire, Lao PDR and Pemba Island

Abstract Routine monitoring of occurrence, levels and mechanisms of insecticide resistance informs effective management strategies, and should be used to assess the effect of new tools on resistance. As part of a cluster randomised controlled trial evaluating a novel insecticide-based intervention in central Côte d’Ivoire, we assessed resistance and its underlying mechanisms in Anopheles gambiae populations from a subset of trial villages. Resistance to multiple insecticides in An. gambiae s.s. and An. coluzzii was detected across villages, with dose–response assays demonstrating extremely high resistance intensity to the pyrethroid deltamethrin (> 1,500-fold), and mortality following exposure to pyrethroid-treated bednets was low (< 30% mortality in cone bioassays). The 1014F kdr mutation was almost fixed (≥ 90%) in all villages but the 1575Y kdr-amplifying mutation was relatively rare (< 15%). The carbamate and organophosphate resistance-associated Ace-1 G119S mutation was also detected at moderate frequencies (22–43%). Transcriptome analysis identified overexpression of P450 genes known to confer pyrethroid resistance (Cyp9K1, Cyp6P3, and Cyp6M2), and also a carboxylesterase (COEAE1F) as major candidates. Cyp6P3 expression was high but variable (up to 33-fold) and correlated positively with deltamethrin resistance intensity across villages (r2 = 0.78, P = 0.02). Tools and strategies to mitigate the extreme and multiple resistance provided by these mechanisms are required in this area to avoid future control failures.

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The effects of iron fortification on the gut microbiota in African children: a randomized controlled trial in Côte d'Ivoire

American Journal of Clinical Nutrition ◽

10.3945/ajcn.110.004564 ◽

2010 ◽

Vol 92 (6) ◽

pp. 1406-1415 ◽

Cited By ~ 246

Author(s):

Michael B Zimmermann ◽

Christophe Chassard ◽

Fabian Rohner ◽

Eliézer K N'Goran ◽

Charlemagne Nindjin ◽

...

Keyword(s):

Randomized Controlled Trial ◽

Gut Microbiota ◽

Cote D'ivoire ◽

Côte D’Ivoire ◽

Controlled Trial ◽

Iron Fortification ◽

Cote D’Ivoire ◽

Randomized Controlled ◽

African Children ◽

Côte D'ivoire

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Spatial targeting of Screening + Eave tubes (SET), a house-based malaria control intervention, in Côte d’Ivoire: A geostatistical modelling study

PLOS Global Public Health ◽

10.1371/journal.pgph.0000030 ◽

2021 ◽

Vol 1 (11) ◽

pp. e0000030

Author(s):

Tiago Canelas ◽

Edward Thomsen ◽

Daniel McDermott ◽

Eleanore Sternberg ◽

Matthew B. Thomas ◽

...

Keyword(s):

Malaria Transmission ◽

Malaria Control ◽

Cote D'ivoire ◽

Côte D’Ivoire ◽

Controlled Trial ◽

Cluster Randomised Controlled Trial ◽

Clinical Malaria ◽

Cote D’Ivoire ◽

Côte D'ivoire ◽

Ground Truthing

New malaria control tools and tailoring interventions to local contexts are needed to reduce the malaria burden and meet global goals. The housing modification, screening plus a targeted house-based insecticide delivery system called the In2Care® Eave Tubes, has been shown to reduce clinical malaria in a large cluster randomised controlled trial. However, the widescale suitability of this approach is unknown. We aimed to predict household suitability and define the most appropriate locations for ground-truthing where Screening + Eave Tubes (SET) could be implemented across Côte d’Ivoire. We classified DHS sampled households into suitable for SET based on the walls and roof materials. We fitted a Bayesian beta-binomial logistic model using the integrated nested Laplace approximation (INLA) to predict suitability of SET and to define priority locations for ground-truthing and to calculate the potential population coverage and costs. Based on currently available data on house type and malaria infection rate, 31% of the total population and 17.5% of the population in areas of high malaria transmission live in areas suitable for SET. The estimated cost of implementing SET in suitable high malaria transmission areas would be $46m ($13m –$108m). Ground-truthing and more studies should be conducted to evaluate the efficacy and feasibility of SET in these settings. The study provides an example of implementing strategies to reflect local socio-economic and epidemiological factors, and move beyond blanket, one-size-fits-all strategies.

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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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