Rock Aïkpon

The Plasmodium transmission-blocking endosymbiont Microsporidia MB was previously identified in Anopheles gambiae s.l., but its association with the carria

Les espèces de blattes domestiques sont connues pour être des insectes nuisibles et vecteurs d’agents pathogènes. Pour lutter contre les battes, des insecticides génériques pour la plupart des pyréthrinoïdes sont souvent utilisés. Il est cependant nécessaire de disposer d’un produit efficace et ne ciblant que les blattes avec un protocole simple de désinsectisation. Cette étude avait pour but d’évaluer le potentiel insecticide de ADVION GEL sur les espèces de blattes domestiques. Des captures de blattes ont été réalisées suivi de leur élevage dans des terrariums pour disposer de colonies suffisantes pour l’évaluation. Dans les chambres expérimentales, différentes doses de 0,2 g/m², 0,3 g/m², 0,4 g/m², 0,5 g/m², soit 2 à 5 gouttes de 0,1 g/goutte par m² ont été évaluées. ADVION GEL a induit un effet létal chez les colonies de blattes 12h de temps après exposition et évolue de façon croissante. Les mortalités optimales (100%) ont été observées pour les doses 0,3 g/m2 et 0,4 g/m2 à 72 h. En plus, la dose de à 0,5 g/m2 a donné une mortalité optimale de 100% déjà à 48h. Les doses d’application recommandables pour une action optimale et rapide sont 0,3 g/m2 à 0,5 g/m2 en fonction de l’ampleur de l’infestation. Domestic cockroach species are known to be pests and vectors of pathogens. To control cockroaches, generic insecticides for most pyrethroids are often used. It is therefore necessary to have an effective product targeting only cockroaches, with a simple disinsectization protocol. The aim of this study was to assess the insecticidal potential of ADVION GEL on domestic cockroach species. Cockroaches were captured and reared in terrariums to provide sufficient colonies for evaluation. In the experimental chambers, different doses of 0.2g/m², 0.3 g/m², 0.4 g/m², 0.5 g/m², i.e. 2 to 5 drops of 0.1 g/drop per m² were evaluated. ADVION GEL induced a lethal effect in cockroach colonies 12 hours after exposure, and this effect progressively increases. Optimum mortality (100%) was observed for doses of 0.3 g/m2 and 0.4 g/m2 at 72 hours. In addition, the 0.5 g/m2 dose gave an optimum mortality of 100% already at 48h. Recommended application rates for optimum and rapid action are 0.3 g/m2 to 0.5 g/m2, depending on the spread of the infestation.

Les connaissances traditionnelles sur les plantes et leurs recettes utilisées contre les moustiques, transmises de génération en génération, sont menacées de disparition. Il devient donc crucial de les documenter et de capitaliser leur efficacité afin de favoriser la création de nouveaux biopesticides au bénéfice de la lutte anti-vectorielle. Cette étude ethnopharmacologique a été menée au Bénin auprès de 180 tradipraticiens et experts locaux, sélectionnés dans les trois zones bioclimatiques que compte le pays. Elle a permis de faire le point des connaissances traditionnelles et de déterminer l'importance locale des espèces grâce à la Fréquence Relative de Citation (FRC). Au total, 19 espèces végétales appartenant à 17 genres et 13 familles ont été répertoriés, avec une représentativité relative des Lamiaceae et Rutaceae. Les espèces les plus couramment utilisées sont Syzygium aromaticum (27,8%), Hyptis suaveolens (17,8%), et Ocimum gratissimum (15,0%). Les feuilles, fleurs et tiges feuillées sont principalement employées, souvent par fumigation ou application cutanée directe. Certaines recettes utilisent plusieurs espèces en combinatoire. Les combinaisons Syzygium aromaticum x Citrus aurantiifolia (27,8%), Ocimum gratissimum x Chromolaena odorata (15,0%), et Hyptis suaveolens x Cymbopogon citratus (11,7%) ont été les plus rapportées. Des recherches supplémentaires sont nécessaires pour capitaliser ces procédés et évaluer leur efficacité à travers des essaies entomologiques. Traditional knowledge about plants and their recipes used against mosquitoes, passed down from generation to generation, is at risk of disappearing. Therefore, it is crucial to document and capitalize on their effectiveness to promote the creation of new biopesticides for the benefit of vector control. This ethnopharmacological study was conducted in Benin with 180 traditional healers and local experts selected from the country's three bioclimatic zones. It provided an overview of traditional knowledge and determined the local importance of species through the Relative Citation Frequency (RCF). In total, 19 plant species belonging to 17 genus and 13 families were recorded, with a relative representation of the Lamiaceae and Rutaceae families. The most commonly used species are Syzygium aromaticum (27.8%), Hyptis suaveolens (17.8%), and Ocimum gratissimum (15.0%). Leaves, flowers, and leafy stems are mainly used, often through fumigation or direct skin application. Some recipes use multiple species in combination. The combinations Syzygium aromaticum x Citrus aurantiifolia (27.8%), Ocimum gratissimum x Chromolaena odorata (15%), and Hyptis suaveolens x Cymbopogon citratus (11.7%) were the most reported. Further research is needed to capitalize on these processes and evaluate their effectiveness through entomological trials.

Background: In 2020, Benin has implemented a digitalized mass distribution campaign of insecticide-treated nets (ITNs) in the particular context of COVID-19 pandemic. This paper describes the implementation process as well as the challenges and lessons learned from this campaign. Methods: A descriptive design was used for reporting the planning and implementation process of ITNs campaign. Moreover, the changes and adaptations related to COVID-19 pandemic are described. Results: A total of 3,175,773 households were registered corresponding to a total of 14,423,998 persons (13.55% more from projection). Moreover, 94.16% (13,581,637 people) of enumerated population were protected. A total of 7,652,166 ITNs were distributed countrywide. Conclusions: High political commitment, engagement and support add to the financial and technical supports from partners were the essential factors that make 2020 ITNs mass campaign success in Benin despite the particular context of COVID-19 pandemic. It is essential to maintain the prevention activities for malaria and this could substantially reduce the overall impact of the COVID-19 pandemic for the populations at malaria risk.

Background: In 2020, Benin has implemented a digitalized mass distribution campaign of insecticide-treated nets (ITNs) in the particular context of COVID-19 pandemic. This paper describes the implementation process as well as the challenges and lessons learned from this campaign. Methods: A descriptive design was used for reporting the planning and implementation process of ITNs campaign. Moreover, the changes and adaptations related to COVID-19 pandemic are described. Results: A total of 3,175,773 households were registered corresponding to a total of 14,423,998 persons (13.55% more from projection). Moreover, 94.16 % (13,581,637 people) of enumerated population were protected. A total of 7,652,166 ITNs were distributed countrywide. Conclusions: High political commitment, engagement and support add to the financial and technical supports from partners were the essential factors that make 2020 ITNs mass campaign success in Benin despite the particular context of COVID-19 pandemic. It is essential to maintain the prevention activities for malaria and this could substantially reduce the overall impact of the COVID-19 pandemic for the populations at malaria risk.

Background: In May 2019, a confirmed dengue fever case was detected at the local hospital of Abomey-Calavi Commune in southern Benin. In Benin, there remains a dearth of literature concerning the distribution and biology of Aedes aegypti, the principal vector of dengue fever. This study was initiated by the Ministry of Health to partially fill this gap. The findings allowed us to assess the arboviral transmission risk incurred by the population of Abomey-Calavi to support programmatic decision-making. Methods: Entomological assessments were conducted in 5% of the houses, meaning 314 houses selected from 11 boroughs in Abomey-Calavi Centre district and 9 villages in Hêvié district. The surveyed breeding sites were water containers located in (domestic) and around (peri-domestic) the dwellings. When a container was positive (housing larvae), a portion of the immature population was sampled with a larval dipper and poured into labeled jars. Immatures were then reared to adulthood at the Centre de Recheche Entomologique de Cotonou (CREC) insectary. Adult mosquitoes were morphologically identified to species level by site and, a subsample of the collected Ae. aegypti mosquitoes were used for WHO susceptibility tube tests. Results: Of the 1372 adult Aedes specimens which emerged from the collected larvae and pupae, 1356 Ae. aegypti (98.83%), 10 Ae. luteocephalus, and 4 Ae. vittatus were identified. The Breteau indices were 160.2 in Abomey-Calavi Centre and 150 in Hêvié, whereas the House indices were 58.5% and 61.6% in the respective districts. WHO insecticide susceptibility tube tests showed that the mortality rates were 38.71% in Abomey-Calavi Centre and 85.71% in Hêvié for permethrin, and 72.22% in Abomey-Calavi Centre and 100% in Hêvié for deltamethrin. Conclusion: The two districts were highly infested by Ae. aegypti whose breeding sites were mostly man-made. Considering this, human behavioral change to substantially reduce the number of larval habitats is necessary to control the vector populations. As Aedes mosquitoes are day biters, the use of repellents such as ointments and smoke coils can also be useful.

Background: In Benin, malaria vector control mostly relies on long-lasting, insecticidal-treated bed nets (LLINs) and indoor residual spraying (IRS) operations. From 2011 to 2016, an IRS programme has been implemented in Atacora region. However, in 2017 the programme was withdrawn from two other regions in the northern part of the country, with hopes that gains would be relatively sustained because of the seasonality of malaria transmission. What would be the vulnerability of populations to malaria after the withdrawal of IRS? Methods: Monthly mosquito collections were performed through human landing captures (HLCs) for 24 months (from January to December 2016 during the last IRS campaign, and from January to December 2018, 2 years after the withdrawal of IRS). Vector mosquitoes biting density was sampled by HLC and was tested for presence of Plasmodium falciparum sporozoites. The carcass of these mosquitoes (abdomens, wing, legs) were subjected to molecular species identification using polymerase chain reaction (PCR) assays. Results: It is noticed a drastic increase (~ 3 times higher) of vector abundance after the withdrawal of IRS. Mosquito biting rates in the 3 survey districts increased significantly after IRS was withdrawn. In 2018, after IRS cessation a significant increase of entomological inoculation rate was recorded, where each inhabitant received an average of 94.9 infected bites/year to 129.21 infected bites/year against an average of 17.15 infected bites/year to 24.82 infected bites/year in 2016. Conclusion: It is obvious that the withdrawal of IRS confers a vulnerability of the population with regard to the malaria transmission. Robust monitoring is needed to better understand when and where IRS should be most adequate, or can be safely withdrawn. In case of withdrawal, adapted accompanying measures should be proposed according to the context not only to maintain the gains capitalized with IRS, but also to avoid any rebound of transmission.

Background: The current study shows the results of three years of IRS entomological monitoring (2016, before intervention; 2017 and 2018, after intervention) performed in Alibori and Donga, northern Benin. Methods: Mosquito collections were performed on a monthly basis using human landing catches and pyrethrum spray catches in six districts including four treated with Actellic 300 CS (Kandi, Gogounou, Djougou and Copargo) and two untreated (Bembèrèkè and Kouandé) which served as control sites. Key transmission indicators of Anopheles gambiae (s.l.) as well as the residual activity of Actellic 300 CS assessed through WHO cone tests, were determined. Results: The residual efficacy duration of Actellic 300 CS after the two IRS campaigns (2017 and 2018) was 4–5 months (May–September). The parity rate and the sporozoite index of An. gambiae (s.l.) were 36.62% and 0.71%, respectively, after the first spray round in treated areas compared to 57.24% and 3.7%, respectively, in the control areas (P < 0.0001). The same trend was observed after the second spray round. After the first spray round, each person received 1.6 infective bites/month (ib/m) in the treated areas against 12.11 ib/m in the control areas, resulting in a reduction rate of 86.78%. Similarly, the entomological inoculation rate was 1.5 ib/m after the second spray round in the treated areas vs 9.75 ib/m in the control areas, corresponding to a reduction of 84.61%. A decrease in the parity rate (46.26%), sporozoite index (85.75%) and EIR (87.27%) was observed for An. gambiae (s.l.) after the first round of IRS (June–October 2017) compared to the pre-intervention period (June–October 2016). The density of An. gambiae (s.l.) ranged between 0.38–0.48 per house in treated areas vs 1.53–1.76 An. gambiae (s.l.) per house respectively after the first and second IRS rounds. Conclusions: This study showed the positive impact of IRS in reducing key entomological parameters of malaria transmission in Alibori and Donga. However, the considerable blood-feeding rate of An. gambiae (s.l.) in spray areas, stress the need for the population to sleep under long-lasting insecticidal nets (LLINs) in addition, to prevent from mosquito bites which did not succeed in resting on sprayed walls.

This study aims to provide baseline data on the resistance status to insecticides, the frequency of mechanisms involved and the impact of the association with the synergist piperonyl butoxide (PBO) on resistant Anopheles gambiae (s.l.) populations in two regions of northern Benin, prior to an indoor residual spraying campaign and introduction of next generation long-lasting insecticidal nets (LLINs) incorporating PBO. Adult Anopheles gambiae (s.l.) originating from larvae collected in two study regions (Alibori within the Kandi-Gogounou-Segbana districts and Donga within the Djougou-Copargo-Ouake districts) were tested with impregnated papers (bendiocarb 0.1%, pirimiphos-methyl 0.25%, permethrin 0.75% and deltamethrin 0.05%). The synergist PBO was used to check for the involvement of detoxification enzymes in pyrethroid resistant populations. Molecular analyses were performed for the identification of species within the Anopheles gambiae (s.l.) complex and kdr L1014F and G119S Ace-1 mutations. Biochemical assays assessed the activity of detoxification enzymes. Anopheles gambiae (s.l.) was resistant to pyrethroids, with a mortality range of 25–83% with deltamethrin and 6–55% with permethrin. A significant increase in mortality was observed after pre-exposure to PBO for both deltamethrin (63–99%) and permethrin (56–99%). With bendiocarb, An. gambiae (s.l.) were susceptible in Kandi (99% mortality), with possible resistance (92–95%) recorded in Djougou, Copargo, Gogounou, Ouake and Segbana. All study populations were fully susceptible to pirimiphos-methyl. The frequencies of resistant mutations varied according to species and sites: 0.67–0.88 for L1014F kdr and 0–0.06 for G119S Ace-1. Three study locations (Djougou, Gogounou and Kandi) showed high oxidase activity and four sites (Djougou, Ouake, Copargo and Kandi) showed elevated esterase activity. This study confirms resistance to pyrethroids and suggests emerging bendiocarb resistance in An. gambiae (s.l.) populations in northern Benin. However, recovery of susceptibility to pyrethroids after PBO exposure, and susceptibility to organophosphates in the An. gambiae (s.l.) populations indicate that next generation LLINs incorporating PBO synergist combined with an indoor residual spraying (IRS) campaign with organophosphate insecticides may be regarded as alternative control tools.

From 2008 to 2013, a prevention intervention against malaria based on indoor residual spraying (IRS) was implemented in Benin. From 2008 to 2012, Ficam M®, a bendiocarb-containing product was used for house spraying, in association with pirimiphos methyl EC (Actellic EC) in 2013. This operation aimed to strengthen the effectiveness of treated nets so as to expedite the achievement of Millennium Development Goals (MDGs): the reduction of morbidity and mortality due to malaria by 75 % from 2000 to 2015. Monitoring and evaluation (M&E) was implemented in order to evaluate the impact of IRS intervention on malaria transmission. Anopheles gambiae s.l. populations were sampled by human landing catch. In addition, window exit traps and pyrethrum spray catches were performed to assess exophagic behaviour of Anopheles vectors the main malaria vector in the treated areas. The residual activity of insecticide in the treated walls was also assessed using WHO bioassay test. The purpose of this project was to draw attention to new challenges and future prospects for the success of IRS in Benin. The main strength of the intervention was a large-scale operation in which more than 80 % of the houses were treated due to the strong adhesion of population. In addition, a significant reduction of the EIR in areas under IRS were observed. However, there were many challenges including the high cost of IRS implementation and the identification of suitable areas to implement IRS. This was because of the low and short residual effect of the insecticides recommended for IRS and the management strategy for vector resistance to insecticides. This indicated that challenges are accompanied by suggested solutions. For the cost of IRS to be accessible to states, then local organizations need to be created in partnership with the National Malaria Control Programme (NMCP) in order to ensure relevant planning and implementation of IRS. As an anticipatory measure against vector resistance, this paper proposes various methods, such as periodic IRS based on a combination of two or three insecticides of different classes used in rotation every two or three years.