Nouhoun Traoré

Background: Anopheles funestus s.s plays a major role in sustaining residual malaria transmission in many African settings. Despite its epidemiological importance, research on its biology and developing effective control strategies is greatly hindered by the persistent challenges associated with establishing stable colonies in laboratory. Here we describe the successful establishment of a new laboratory strain in Burkina Faso (FUNBF). Methods: Adult female mosquitoes were collected in Diébougou and Soumousso using mouth and battery-powered electric aspirators. These mosquitoes were morphologically identified as belonging to the An. funestus group. Individual females were allowed to oviposit separately in 200 mL disposable cups. Female mosquitoes were then confirmed at the molecular level as An. funestus s.s. Adults were maintained at 27 ± 2 °C and 60–80% relative humidity under a 12:12 h light–dark cycle, while larvae were kept at 29 ± 2 °C under the same light–dark cycle. Fecundity and fertility were recorded for F0 and F24, whereas larval development time, emergence rate, blood-feeding rate, oviposition rate, and mating performance were assessed in F24. Results: A total of 1871 female mosquitoes were collected across two years to establish the colony. F0 and F24 showed comparable fecundity, with mean egg loads of 85.33 (95% CI: 79.43–91.24) and 78.87 (95% CI: 69.33–88.30) eggs per female, respectively. Mean egg hatching rate was 88.62 (95% CI: 85.79–91.41) and 55.20 (95% CI: 45.77–64.64) at FO and F24 respectively. The mean pupation rate was 58.5 (95% CI: 47.81–69) with a median pupation time of 15 days. Adult emergence rates were high in both sexes, with 84.0% ± 3.37% of male pupae and 85.0% ± 5.92% of female pupae successfully emerging as adults; emergence success did not differ significantly between sexes. Females showed a blood-feeding rate of 85.21 (95% CI: 40.45–104.91) with insemination and oviposition rates of 37.5 ± 5.83% ( n = 2) and 37.5 ± 9.17% ( n = 2), respectively. Mortality recorded 24 h after blood feeding was 4.51(95% CI: 0.64–8.37). FUNBF has been maintained successfully for 24 generations with sustained egg production. Conclusions: This work represents a significant advance in the domestication of An. funestus, one of the main malaria vectors in sub-Saharan Africa.

Background: Malaria control tools are nowadays challenged by the expansion and persistence of insecticide resistance in the malaria vector along with the changes in vector behaviour. To complement and reinforce the existing control tools, innovative vector control methods, such as gene drives, are currently under development. Understanding the Anopheles gambiae sensu lato ( An. gambiae s.l. ) population structure is crucial for the implementation of genetic control tools and improvement of existing control strategies. Here we investigated the genetic diversity and population structure of Anopheles gambiae s.l. populations from three climatic zones in Burkina Faso. Method: Mosquito specimens were collected across three ecological settings in Burkina Faso using pyrethroid spray catches. The whole genomes of Anopheles gambiae s.l. specimens were sequenced as part of the Anopheles gambiae 1000 Genomes Project. Data were analysed using MalariaGEN Resources to investigate the genetic diversity and the population structure. Results: The results revealed the absence of geographical population structure in Anopheles coluzzii and Anopheles gambiae sensu stricto ( An. gambiae s.s. ) collected in the three climatic zones, implicating high gene flow within the country. Anopheles arabiensis showed a structure that separates Hauts-Bassins samples in the Soudanian zone from other An. arabiensis samples. The cryptic species ( An. goundry and An. tengrela ) previously identified in the country were not detected in this study. Our findings also indicate population expansion in An. gambiae s.l. ; however, An. arabiensis populations show evidence of a smaller population size or a bottleneck. Conclusion: Our findings could indicate that An. arabiensis has a distinct demographic history. The population structure of An. gambiae s.s. and An. coluzzii across the country is characterized by a lack of geographical differentiation. These findings have important implications for both current vector control strategies and the potential implementation of gene drive technologies. Indeed, the lack of geographical population structure offers the potential for the rapid spread of gene drive constructs.

Anopheles funestus group and Anopheles gambiae complexes are among the most efficient malaria vectors in Africa, thriving in a variety of environm

Malaria transmission in sub-Saharan Africa is dominated by the An. gambiae complex and An. funestus group, whose distribution varies across ecological settings. Secondary species occur at lower densities, but their role in transmission may differ from one locality to another depending on local conditions. Assessing Anopheles biodiversity using ecological indices is therefore essential to characterise their diversity and relative abundance. This study investigated the biodiversity and spatial distribution of Anopheles species across the three climatic zones of Burkina Faso to guide effective vector control strategies. Indoor resting mosquitoes were collected from 67 health districts across the 13 regions of Burkina Faso between September and December 2022 using pyrethroid spray catches. A total of 30,521 Anopheles mosquitoes were identified, with An. gambiae s.l. dominating (94.4%). The Sudano-Sahelian zone recorded the highest abundance, followed by the Soudanian and Sahelian zones. Biodiversity decreased from humid southern to arid northern areas, with the Soudanian zone showing the highest diversity. Molecular analysis of 2026 An. gambiae s.l. specimens revealed marked heterogeneity: An. coluzzii predominated in Sahelian (74.9%) and Sudano-Sahelian (71.2%) zones, while An. gambiae s.s. was most frequent in the Soudanian zone (53.8%). These results highlight spatial and ecological differences in Anopheles composition across Burkina Faso and emphasize the need for locally adapted malaria vector control strategies.

Background/Objectives: Despite the increasing emergence of resistance, insecticide-based tools remain the primary method for malaria vector control in Africa. To maintain the effectiveness of these interventions, continuous monitoring and identification of novel resistance mechanisms is essential. This study aimed to investigate potential new insecticide resistance genes in the Anopheles gambiae complex. Methods: We analyzed whole-genome sequencing data from the An. gambiae 1000 Genomes Project. A broad range of genomic analysis techniques and tools were used to identify and explore genetic variation in the candidate resistance genes. Results: High haplotype homozygosity values, indicative of positive selection, were detected in a 2L chromosomal region corresponding to an aldehyde oxidase gene cluster (AGAP006220, AGAP006221, AGAP006224, AGAP006225, AGAP006226). Single nucleotide polymorphisms (SNPs) have been identified in these genes with frequencies up to 100%, including 569, 691, 1433, 978, and 811 non-synonymous SNPs in AGAP006220, AGAP006221, AGAP006224, AGAP006225, and AGAP006226, respectively. Copy number variations (CNVs) such as deletions and amplifications were also identified at low frequencies (An. gambiae and An. coluzzii. Conclusions: This study provides evidence that aldehyde oxidase genes may contribute to insecticide resistance in An. gambiae s.l. populations. These results highlight the importance of genomic surveillance for detecting novel resistance loci and guiding the development of improved vector control strategies under changing ecological and evolutionary conditions.

Despite the increasing emergence of resistance, insecticide-based tools remain the main strategies used so far for vector control in Africa. In the absence of more effective alternatives, monitoring and screening for new resistance mechanisms remain the main strategies to ensure the continued deployment of current vector control tools. Here, we used the whole genome sequencing data from the Anopheles gambiae 1000 Genomes Project to investigate potential novel insecticide resistance genes in the Anopheles gambiae complex. We used a broad range of genomic data analysis techniques to identify and examine genetic variation in the potential new resistance genes identified. The results showed elevated Garud H12 values in the genomic regions of the 2L chromosome corresponding to the aldehyde oxidase cluster genes (AGAP006220, AGAP006221, AGAP006224, AGAP006225 and AGAP006226). The findings show a high occurrence of the two most common haplotypes in the populations, suggesting a recent selective sweep in this region driven by positive selection. In addition, single nucleotide polymorphisms (SNPs) have been identified in these genes with frequencies up to 100%, including 569, 691, 1433, 978, and 811 non-synonymous SNPs in AGAP006220, AGAP006221, AGAP006224, AGAP006225, and AGAP006226, respectively. Copy number variation (CNVs) such as deletions and amplifications were also identified in these genes at low frequencies (<12%). The analysis of population structure analysis revealed evidence of adaptive and geographic gene flow between An. gambiae and An. coluzzii, confirming the historical connectivity between both species. These findings showed the potential role of aldehyde oxidase genes in the resistance of An. gambiae s.l. populations to insecticides. This study emphasized the importance of genomic surveillance for identifying new potential genes involved in the adaptation of malaria vectors to ecological changes.

The Oriental fruit fly, Bactrocera dorsalis, is a pest of significant economic interest that damages horticulture and causes major economic losses worldwide. The main control measures are based on insecticides, which are being increasingly restricted due to the development of genetic resistance. Therefore, there is a crucial need for a novel, sustainable, and environmentally safe means of controlling this pest. Advances in genome editing, aided by the discovery of CRISPR‐Cas9 tools and the development of gene drive systems, offer new alternatives for combating insect pests and vectors. Genetic suppression tools targeting key parameters could become powerful assets within the AW‐IPM programme for controlling B. dorsalis. This literature review provides an overview of currently characterized genes that could be targeted for genetic suppression of B. dorsalis.

Bactrocera dorsalis Hendel is a highly invasive horticultural pest that is of major economic importance worldwide. In Burkina Faso, it is one of the main insect pests that affects the production and exportation of mangos. Understanding the biology and the genetic dynamics of this insect pest provides crucial information for the development of effective control measures. The aim of this study was to understand the distribution, diversity, and genetic structure of B. dorsalis in Burkina Faso. Male flies were collected transversally in Burkina Faso and analyzed by PCR using 10 microsatellite markers. The results showed an abundance of B. dorsalis varying from 87 to 2986 flies per trap per day at the different sampling sites. The genetic diversity was high at all sites, with an average Shannon’s Information Index (I) of 0.72 per site. The gene flow was high between study populations and ranged from 10.62 to 27.53 migrants. Bayesian admixture analysis showed no evidence of structure, while Discriminant Analysis of Principal Components identified three weakly separated clusters in the population of B. dorsalis in Burkina Faso. The results of this study could be used to optimize the effectiveness of current control interventions and to guide the implementation of new, innovative, and sustainable strategies.

Bactrocera dorsalis Hendel is a highly invasive horticultural pest of major economic importance worldwide. In Burkina Faso, it is one of the main insect pests constraining the mango production and export. Understanding the biology and the genetic dynamics of this insect pest provide cru-cial information for the development of effective control measures. The aim of this study was to understand the distribution, diversity and genetic structure of B. dorsalis in Burkina Faso. Male flies were collected transversally in Burkina Faso and analyzed by PCR using 10 microsatellite markers. The results showed an abundance of B. dorsalis varying from 87 to 2986 flies per trap per day in the different sampling sites. Genetic diversity was high in all sites with an average Shan-non's Information Index (I) of 0.72 per site. Gene flow was high between study populations and ranged from 10.62 to 27.53 number of migrants. Bayesian admixture analysis showed no evi-dence of structure while Discriminant Analysis of Principal Components identified three weakly separated clusters in the population of B. dorsalis in Burkina Faso. The results of this study could be used to optimize the effectiveness of current control interventions and to guide the imple-mentation of new, innovative and sustainable strategies.

1 IntroductionBactrocera dorsalis is one of the major horticultural pests of economic importance worldwide (Peng et al ., 2020; D. D. Weiet al. , 2019) and is classified as a quarantine pest in several countries (Liu et al. , 2019; CABI, 2021). This peculiar insect species has a very high invasive potential, due to a varied range of host plants and high reproductive capacity, combined with up to 100% destruction capacity of horticultural fields, which results in important ecological and economic losses in the affected countries (CABI, 2021; Ekesi et al ., 2009; Liendo et al ., 2018). Its presence in Africa was only detected about 20 years ago (Zhang et al. , 2016; CABI, 2021). However, it was able to surpass Ceratitis cosyra , the previous local fruit pest, in terms of density and damage (Ekesiet al ., 2009; Zida et al ., 2020). B. dorsalis is now the main problem within the horticultural sector in several African countries with over 40 possible host plants known to date (Zhanget al. , 2016; CABI, 2021). Chemical insecticides are currently considered the main method of controlling insect pests and vectors worldwide 2010 (Heve, Adjadeh and Billah, 2021). They were effective in eradicating B. dorsalis in parts of southern Africa such as Mauritius in 2000 and 2013 and the South African province of Limpopo in 2010. They have also reduced mango infestation in other countries such as Benin, Cameroon and Kenya (Mutamiswa et al. , 2021). However, insecticide resistance could compromise future eradication programs (Vontas et al. , 2011) as frequently shown also for other pest and vector insects such as the Mediterranean fruit fly (medfly)Ceratitis capitate (Magaña et al. , 2008), the olive flyBactrocera oleae (Pavlidi et al. , 2018), and the malaria mosquitoes Anopheles gambiae (Namountougou et al. , 2012).Recent advances in molecular biology have prompted the emergence of various genome editing tools. The development of Gene-drive technology, and more recently of the discovery and implementation of CRISPR-Cas9 tools, have revolutionized the field of insect bioengineering (Doudnaet al. , 2014; Hsu, Lander and Zhang, 2014; Oye et al. , 2014; Drury et al. , 2017) applied to the genetic control of harmful insects. Gene-drive systems, empowered by the precision, simplicity and efficiency offered by CRISPR tools, offer a promising tool for controlling insect pests and vectors (Bouyer et al ., 2018; Hammond et al ., 2016) without contributing to the increasing environmental pollution or being affected by resistance to chemical insecticides. The technology is based on the introduction of a genetic element in the insect genome (transgene) able to bias its inheritance, thereby acting as a “selfish” genetic system (Amoet al. , 2020). Deployment of this technology for pest control also has the advantage of being able to impact target populations beyond the point of release and over multiple generations (Quinn et al ., 2020) through spatial and temporal dispersion facilitated by mating reproduction (D. Amo et al ., 2020; Mudziwapasi et al ., 2021; Quinn et al ., 2020; M. J. Scott et al ., 2016; Verkuijl et al ., 2022). Gene-drive technology allows either the suppression or replacement of target populations according to the design of the genetic system introduced (Galizi et al ., 2016; Hammondet al ., 2016, 2021; Kyrou et al ., 2018; Quinn et al ., 2020). Relying on self-propagating elements, gene-drive technologies have the advantage of being easy to deploy as well as cost-effective. Promising results have already been achieved in laboratory settings where gene drives have been developed in insects such as Drosophila melanogaster (Huang, Liu and Rong, 2016; Webster, Vella and Scott, 2020), Aedes aegypti (Li et al. , 2020) and Anopheles gambiae (Hammond et al ., 2021; Kyrouet al ., 2018; Simoni et al ., 2020).The development and implementation of genetic control tools in B. dorsalis could complement existing control programs. Several genes have already been identified through studies as potential targets for this purpose (G. Liu et al ., 2015; Peng et al ., 2020; Xuet al ., 2022; J. Zhang et al ., 2018; Zheng et al ., 2018). This literature review aims to bring together relevant information and available tools to engineer effective genetic control technologies, providing an assessment of current tools and techniques available for the development of genetic control methods and gene-drives in B. dorsalis .