Typologie Des Gîtes Larvaires Et Résistance Des Vecteurs Du Paludisme A La Deltaméthrine Dans les Milieux Urbain Et Rural Du Département De l’Atlantique Au Sud Du Bénin: Données Préliminaires

La lutte antilarvaire récemment recommandée par l’OMS, requiert une connaissance approfondie de la distribution et de la typologie des gîtes larvaires des vecteurs du paludisme. L’objectif de cette étude est d’identifier les différents gîtes larvaires des anophèles et leur mécanisme de résistance à la deltaméthrine. Des prospections larvaires ont été effectuées en 2017 durant les saisons pluvieuses et sèches dans trois communes au sud du Bénin. Les moustiques issus de l’émergence des larves ont été soumis à la deltaméthrine et au bendiocarb selon le protocole de l’OMS. L’identification moléculaire des anophèles et le génotypage de la mutation Kdr ont été réalisés par PCR et l’expression des oxydases, des estérases α et β, et des GST ont été mesurées. Les prospections larvaires ont permis de répertorier 37 gîtes larvaires regroupés en 13 types. La majorité des gîtes étaient anthropiques. La densité larvaire variait d’un type de gîtes à l’autre. An. coluzzii et An. gambiae étaient les deux vecteurs du paludisme vivant en sympatrie dans lestroissites d’étude. Ils sont fortement résistants à la deltaméthrine avec la présence de la mutation kdr à des fréquences très élevées et une augmentation des activités des estérases dans les populations d’anophèles collectés à Zè et des GST à Abomey-Calavi et Allada. La prolifération des vecteurs du paludisme serait imputable à l’insalubrité de l’environnement immédiat et aux activités anthropiques qui créent et assurent le maintien des gîtes larvaires. Ces données pourraient servir au renforcement des stratégies de lutte contre le paludisme déjà en cours. Anopheles larval control, recently recommended by WHO, requires a deep knowledge of the distribution and typology of larval breeding sites. The objective of this study is to identify the different larval habitats colonized by Anopheles and their insecticide resistance mechanism. Larval surveys were carried out in three Districts in south of Benin in 2017, during the rainy and dry seasons. Mosquitoes breeding sites have been characterized and mapped. Mosquitoes from the emergence of larvae were tested to deltamethrin and bendiocarb according to the WHO protocol. The molecular identification of anopheles and the genotyping of the kdr mutation were performed by PCR and the expression of oxidases, esterases, and GSTs was measured. Larval surveys have identified 37 breeding sites categorized into 13 types. Most of the larval habitats were anthropogenics. An. coluzzii and An. gambiae were the two malaria vectors found in sympatric in the three study sites. These two vectors were highly resistant to deltamethrin with the presence of the kdr L1014F mutation at very high frequencies and an increase in esterase activities in anopheline populations collected in Zè and GST in Abomey-Calavi and Allada. The proliferation of malaria vectors is attributable to the unhealthy environment and human activities that create and maintain mosquito breeding. This study highlighted diversity in the type of breeding site of An. gambiae s.s in the Atlantic Department, suggesting the adaptation of this species in its environment. These results could be used to develop an antilarval control strategy in Abomey-Calavi, Zè and in Allada

Minimal tillage and intermittent flooding farming systems show a potential reduction in the proliferation of Anopheles mosquito larvae in a rice field in Malanville, Northern Benin.

BACKGROUND: Irrigation systems have been identified as one of the factors promoting malaria disease around agricultural farms in sub-Saharan Africa. However, if improved water management strategy is adopted during rice cultivation, it may help to reduce malaria cases among human population living around rice fields. This study aimed to assess the impact of the different irrigation practices on malaria transmission, as well as to evaluate the water management system that will best mitigate malaria transmission in Malanville, Benin. METHODS: Knowledge, Attitude and Practice (KAP) study was conducted on 104 households staying on and around the rice fields in Malanville. The study focused on the frequency of mosquito bites and preventive measures against malaria as well as soil preparation and rice planting methods. Mosquito larvae density was assessed in different water management system: continuous flooding (CF) or intermittent flooding (IF), deep tillage (DT) or minimal tillage (MT) and normal levelling (NL) or abnormal levelling (AL) in an experimental hut set-up. Larvae were collected using dipping methods and their density was determined. RESULTS: Three tillage systems, which include the use of tiller, plow and hoe, were identified on the rice field. Continuous flooding was the only irrigation system used by farmers. Retrospective data from Malanville Health Centre revealed higher malaria cases during rice production season, which was also confirmed by field participants. The density of Anopheles larvae was reduced by 80.8%, 30.8% and 40.7% (P = 0.000) during transplanting, tillering and maturation periods, respectively with intermittent flooding compared to continuous flooding. In addition, a clear reduction of larva density was observed with both intermittent flooding systems applied to minimal tillage (MT + IF + NL) and intermittent flooding applied to deep tillage (DT + IF + AL), showing that intermittent flooding could reduce the abundance of malaria vector in rice fields. CONCLUSION: Recommending intermittent flooding technology for rice cultivation may not only be useful for water management but could also be an intentional strategy to control mosquitoes vector-borne diseases around rice farms

Attitudes and prevention towards malaria in the context of COVID-19 pandemic in urban community in Benin, West Africa

Abstract Background The COVID-19 pandemic and its damages have severely impacted the global healthcare system even in countries with the best systems. In sub-Saharan Africa (SSA), it could worsen the malaria situation in endemic countries such as Benin. This study was conducted to describe the potential effects of the pandemic on urban dwellers attitudes, prevention and treatment against malaria in four major cities of Benin. Methods A cross-sectional questionnaire survey was conducted in Cotonou, Bohicon, Parakou and Natitingou, four urban cities of Benin. A total of 800 randomly selected households were interviewed. The questionnaire consisted of four parts: sociodemographic characteristics, knowledge, attitude, and practice. Descriptive statistics and binomial logistic regression analysis were used in the statistical analysis. Results More than 90% of the participants interviewed had a good level of knowledge about the transmission and prevention of malaria in the cities surveyed. In contrast, low proportions of participants reported visiting health-care facilities when they suspected malaria. Compared to the proportions observed at Parakou and Natitingou, the low proportion of participants was statistically significant at Cotonou (Parakou: X 2 = 31.345, df = 1, P < 0.0001; Natitingou: X 2 = 17.471, df = 1, P < 0.0001). Among the reasons for not seeking care, these related to COVID-19 were the most mentioned. Moreover, the good education level of the participants was one of the factors associated with the non-use of healthcare facilities due to over-knowledgeable about Covid-19, which might have increased the fear to go to the health facilities. Finally, high proportions of self-medication practice were mentioned with high use of malaria drugs to treat both malaria and to protect against COVID-19. Conclusions The data show a negative impact of COVID-19 on visits to healthcare facilities for malarial treatment and malaria drugs usage by the population. It is, therefore, necessary to rebuild malaria programmes by integrating measures adapted to health crises such as the COVID-19 pandemic