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Sovi A.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | Govoetchan R.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | Tokponnon F.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | Aikpon R.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | And 8 more authors.
Parasites and Vectors | Year: 2013

Background: The goal of the study is to investigate if local agricultural practices have an impact on malaria transmission in four villages located in the same geographical area within a radius of 15 kilometers. Among the villages, one (Itassoumba) is characterized by the presence of a large market garden and fishpond basins, the three others (Itakpako, Djohounkollé and Ko-koumolou) are characterized by traditional food-producing agriculture. Methods. Malaria transmission was evaluated using human-landing catches, both indoors and outdoors, two nights per month for 12 months. Field collected females An. gambiae s.l. were exposed for 1 hour to 0.75% permethrin and 0.05% deltamethrin using WHO insecticide susceptibility test kits and procedures. The presence of the kdr mutation was analyzed by PCR. Results: Anopheles gambiae s.s form M (93.65%), was identified as the main malaria vector. Its susceptibility level to pyrethroids was the same (p > 0.05) in all villages. kdr mutation frequencies are 81.08 in Itakpako, 85 in Itassoumba, 79.73 in Djohounkollé and 86.84 in Ko-Koumolou (p = 0.63). The entomological inoculation rate ranged from 9.62 to 21.65 infected bites of An. gambiae per human per year in Djohounkollé, Itakpako and Ko-Koumolou against 1159.62 in Itassoumba (p < 0.0001). Conclusion: The level of resistance of An. gambiae to pyrethroids was the same in the four villages. The heterogeneous character of malaria epidemiology was confirmed. The creation of fishponds basins and the development of market-gardening activities increased drastically the malaria transmission in Itassoumba. © 2013 Sovi et al.; licensee BioMed Central Ltd. Source


Gnanguenon V.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | Azondekon R.,University of Massachusetts Amherst | Beach R.,Centers for Disease Control and Prevention | Akogbeto M.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi
BMC Infectious Diseases | Year: 2014

Background: LLIN distribution, every three years, is a key intervention of Benin's malaria control strategy. However, data from the field indicate that LLIN lifespan appears to vary based on both intrinsic (to the LLIN) and extrinsic factors.Methods: We monitored two indicators of LLIN durability, survivorship and integrity, to validate the three-year-serviceable-life assumption. Interviews with net owners were used to identify factors associated with loss of integrity.Results: Observed survivorship, after 18 months, was significantly less (p<0.0001) than predicted, based on the assumption that nets last three years. Instead, it was closer to predicted survivorship based on a two-year LLIN serviceable life assumption (p=0.03). Furthermore, the integrity of nearly one third of 'surviving' nets was so degraded that they were in need of replacement. Five factors: washing frequency, proximity to water for washing, location of kitchen, type of cooking fuel, and low net maintenance were associated with loss of fabric integrity.Conclusion: A two-year serviceable life for the current LLIN intervention in Benin would be a more realistic program assumption. © 2014 Gnanguenon et al.; licensee BioMed Central Ltd. Source


Aizoun N.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | Osse R.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | Aikpon R.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | Padonou G.G.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi | Akogbeto M.,Faculte Des Science Et Techniques Of Luniversite Dabomey Calavi
Parasites and Vectors | Year: 2013

Abstract. Background: The detection of insecticide resistance in natural populations of Anopheles vectors is absolutely necessary for malaria control. In the African region, the WHO insecticide susceptibility test is the most common method for assessing resistance status. In order to search for a simple, rapid and more reliable technique in the assessment of insecticide resistance in malaria vectors, we compared the WHO tests with the CDC bottle bioassay in the Ouemé province of southern Benin where insecticide resistance has been widely reported. Methods. Larvae and pupae of Anopheles gambiae s.l. mosquitoes were collected from the breeding sites in Ouemé. WHO and CDC susceptibility tests were conducted simultaneously on unfed female mosquitoes aged 2-5 days old. WHO bioassays were performed with impregnated papers of deltamethrin (0.05%) and bendiocarb (0.1%), whereas CDC bioassays were performed with stock solutions of deltamethrin (12.5 μg per bottle) and bendiocarb (12.5 μg per bottle). PCR techniques were used to detect species, Kdr and Ace-1 mutations. CDC biochemical assays using synergists were also conducted to assess the metabolic resistance. Results: A slight decrease in mortality rates was observed with 97.95% and 98.33% obtained from CDC and WHO bioassays respectively in populations of mosquitoes from Adjara and Dangbo. PCR revealed that all specimens tested were Anopheles gambiae s.s. The Kdr mutation was found at high frequency in all populations and both the Kdr mutation and mono-oxygenase enzymes were implicated as mechanisms of pyrethroid resistance in An. gambiae from Misserete. Conclusion: This study emphasizes that both WHO and CDC bioassays give similar results with regards to the susceptibility of mosquitoes to insecticides in southern Benin. There were complementarities between both methods, however, some specificity was noted for each of the two methods used. Both Kdr and metabolic mechanisms were implicated in the resistance. © 2013 Aïzoun et al.; licensee BioMed Central Ltd. Source

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