The trophic behavior of Aedes aegypti at Dandji, a neighbourhood of Cotonou located in southern Benin was evaluated trough a cross-sectional study where adults of Ae. Aegypti populations were collected from May to July 2022 daily twice a week by Human Landing Catch and BG-Sentinel traps. From the total of 717 Aedes collected by different methods, Ae. Aegypti is more abundant in urban than peri-urban areas (p<0.05). The aggressive density of Ae. aegypti populations was significantly higher in urban areas (102.89 bites per man per hour) than in peri-urban areas (52.85 bites per man per hour) (p<0.05). Also, out of 160 females blood-fed Ae. Aegypti tested by ELISA (Enzyme Linked Immunosorbent Assay) technique for blood meal identification, 90% took their blood meal on humans compared to 6.5% which took their blood meal on sheeps. These findings showed that the neighbourhood Dandji in southern Benin offered good condition for the development of Ae. aegypti populations. The anthropology and endophagy behavior of Ae. aegypty observed from this study need to be considered as a tool to control this mosquito.

Background: In order to know the level of malaria transmission in the city of Karimama in the north East of Benin, an entomological study was carried out in this city from January to December 2020. Method : Firstly, the study was based on sampling adults mosquitoes by Human Landing Catches (HLC) in two villages performed monthly over two consecutive nights (8:00 PM to 6:00 AM) in 4 randomly selected compounds. These populations of mosquitoes were completed by Indoor Pyrethrum Spray Catches (PSC) in 10 other selected compounds; the same compounds in each sampling method being consistently used throughout the study. The head-thoraces of these females from the human landing catches were tested for the presence of CircumSporozoite Protein (CSP). Finally, Knocked down mosquitoes falling on white bed sheets were preserved for identification of species and characterization of molecular forms within the An. gambiae complex were performed using Polymerase Chain Reaction (PCR). Results: i)-During the year of study, 9.019 female mosquitoes were caught by PSC against 21.474 by HLC among which, 26% were Anopheles species from HLC; ii)- In this city surveyed, the main malaria parasite Plasmodium falciparum was transmitted by Anopheles gambiae s.s where transmission was high from June to October during the rainy season and declined during the dry season (December-May); iii) - The Entomological Inoculation Rates (EIRs) were significantly higher (138 infection bites/person/night) during the rainy season than those obtained during the dry season (138 infection bites/person/night) (P<0.05). Conclusion: The present study showed that malaria transmission is unimodal in the city of Karimama and the main malaria parasite, Plasmodium falciparum was transmitted by Anopheles gambiae s.s. These findings will be very useful for National Malaria Control Program authorities in the choice of the method to fight against malaria in this city.

For better management of the use of insecticide in public health against Culex quinquefasciatus, an arboviral and filarial vector, a study was conducted at Natitingou, a town located in northern Benin, from October 2015 to March 2016, to evaluate the susceptible of this mosquito to insecticides and the mechanisms of resistance developed. The protocol was based on mosquito collection during both dry and rainy seasons across the four areas selected in northern Benin. Bioassays were performed on adult mosquitoes collected from the field to assess the susceptibility of filarial vectors to insecticide-impregnated papers (permethrin 0.75%, delthamethrin 0.05%, DDT 4%, and bendiocarb 0.1%) following WHOPES guidelines. Moreover, mosquitoes from the susceptible tests were used to search for the presence of the knock down resistance (Kdr) and the Acethylcholinesterase (Ace-1R) mutations. Finally, F1 generation of the wild population of Cx. quinquefasciatus were used for biochemical analysis to target Mixed Function Oxidase (MFO), non-speci?c esterase (NSE) and glutathione-S-transferases (GST) enzymes. This research showed: 1)-A wide spread of resistance to permethrin, delthamethrin and DDT was found in samples of Cx. quinquefasciatus despite the collection areas with 4%; 7% ; 19% and 60% as average of mortality respectively with DDT, permethrin, deltamethrin and bendiocarb; 2)- The kdr mutation was detected in all areas at various frequencies (0.8 to 0.88) whereas the Ace-1 mutation was found at a very low frequency (? 5%); 3) - Enzymes activities (oxidase, esterase and glutathion-S-transferases) were detected in all mosquito populations despite the areas of collection. This work has highlighted the high resistance of Cx. quinquefascitus to the 3 classes of insecticides used in public health. Moreover, the high frequency of kdr and the presence of enzyme activity in Cx. quinquefasciatus will augment the existing data on the insecticide resistance of filariasis vectors and will be useful for making decision to control this mosquito.