Organophosphate and carbamate susceptibility profiling of Anopheles gambiae sl. across different ecosystems in southern Benin

Background To overcome the spread of high pyrethroid resistance in the main malaria vectors and malaria disease persistence, it is crucial to look for effective and better resistance management strategies. Understanding the phenotypic profile of Anopheles gambiae sl. against alternatives insecticides like organophosphates and carbamates is crucial. Methods Anopheles larvae and pupae were collected from the breeding sites in rice fields, pineapple crop areas, and peri-urban areas. WHO susceptibility tests were conducted on unfed female mosquitoes aged 3–5 days old. Mosquitoes were exposed to malathion 5%, pirimiphos-methyl 0.25%, and bendiocarb 0.1% using the standard WHO protocol. Polymerase chain reaction (PCR) techniques were used to detect species, kdr and Ace-1 mutations. Results Anopheles gambiae sl. from Sèdjè-Dénou rice field population was resistant to bendiocarb (0.1%) with a mortality rate of 72.2% whereas Anopheles gambiae sl. populations from Zinvié-Dokomey (rice field), Zè-Tozounmè (pineapple field), and Adjagbo (peri-urban area) were suspected to be resistant with mortality rates of 90%, 93.5%, 95.4% respectively. However, all of them were susceptible to organophosphates (malathion and pirimiphos-methyl) with a mortality rate of 100%. PCR assay revealed that 100% of the mosquitoes tested were Anopheles coluzzii. The frequencies of Ace-1R mutation in all Anopheles coluzzii populations tested were low (3–27%). Conclusions Organophosphates (malathion and pirimiphos-methyl) have maintained their efficacy against Anopheles coluzzii populations from Sèdjè-Dénou (rice field), Zè Tozounmè (pineapple field), Zinvié Dokomey (rice field), or Adjagbo (peri-urban area). The good efficacy of these organophosphates against Anopheles coluzzii populations from the southern part of Benin are observed in the current study. The use of pirimiphos-methyl for IRS in this part of the country would be a successful alternative for malaria control in this area

Resistance to neonicotinoids is associated with metabolic detoxification mechanisms in Anopheles coluzzii from agricultural and urban sites in southern Benin

Background: Neonicotinoids are gradually being introduced into malaria vector control due to their mode of action that targets insect nicotinic acetylcholine receptors (nAChRs). However, prior to scaling up novel insecticides, it is important to assess the susceptibility of the mosquito population to this molecule. The present study aimed to determine the susceptibility level of mosquitos collected from agricultural and urban sites against neonicotinoids in Benin. Material and methods: An. gambiae sl. larvae were collected from three urban sites and two agricultural sites in southern Benin. An. gambiae sl. larvae collected from three urban and two agricultural sites in southern Benin were exposed to neonicotinoids (clothianidin, acetamiprid, and imidacloprid) for 1 hour, and mortality rates were monitored from 24h to day 7 post-exposure. After molecular identification of the samples, Taqman assays were used to genotype key pyrethroid-resistant markers, and qPCRs were performed to establish the level of expression of detoxification enzymes in resistant mosquitoes. Results: Overall, resistance to acetamiprid and imidacloprid was observed in the five study sites surveyed whereas full susceptibility was recorded to clothianidin. Anopheles coluzzii was the only species found in all sites. TaqMan genotyping showed a very low presence of key pyrethroid-resistant markers suggesting that metabolic resistance is more implicated in neonicotinoid resistance in Anopheles. coluzzii populations from southern Benin. qPCR performed revealed overexpression of P450 genes (CYP6M2, CYP6P4, CYP6Z1, CYP6Z2, and CYP4G16) and sensory proteins (Sap1, Sap2, and Sap3). Conclusion: This first assessment of neonicotinoid resistance in Benin showed evidence of neonicotinoid resistance in both agricultural and urban areas. However, full susceptibility to clothianidin was observed, showing that this insecticide could be used to enhance the efficacy of control tools. In addition, there is a need of an integrated approach, including coordinated education on pesticide use, to improve the overall management of insecticide resistance in both agricultural and public health sectors

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