Bactéries et moisissures associées à Musca domestica L. et à Chrysomya chloropyga Wied. (Diptera : Muscomorpha) collectées sur deux sites à environnements différents de la ville de Lomé

Objectif: La présente étude a pour objectif de rechercher les bactéries et les moisissures de l’exosquelette de Musca domestica L. et de Chrysomya chloropyga Wied., deux espèces de mouches synanthropiques abondantes dans les marchés de denrées alimentaires de la ville de Lomé.Méthodologie et résultats: Les deux espèces de mouches ont été collectées dans cinq marchés et dans un Jardin botanique de la ville de Lomé. La technique classique d’isolement et d’identification des bactéries et des moisissures a été utilisée pour rechercher les microorganismes associés à ces deux espèces de mouches. Sur 180 individus de chaque espèce de mouche collectés, les analyses ont permis d’identifier 11 espèces de bactéries : Escherichia coli, Enterobacter agglomerans, Klebsiella spp, Proteus mirabilis, Proteus rettgeri, Proteus vulgaris, Proteus spp, Shigella spp, Staphylococcus aureus, Staphylococcus à coagulase négative et Pseudomonas spp, et 2 espèces de moisissures : Aspergillus niger et Rhizopus spp dans les marchés tandis que dans le Jardin botanique, environnement sans denrées alimentaires, seulement 3 espèces de bactéries (Proteus vulgaris, Proteus spp, Staphylococcus aureus) et de moisissures (Aspergillus niger, Rhizopus spp et Mucor spp) ont été identifiées.Conclusion et application des résultats: La diversité des espèces microbiennes véhiculées par ces mouches capturées au sein des marchés varie suivant les sites et serait liée à la qualité hygiénique de leur l’environnement. M. domestica et C. chloropyga sont de potentiels vecteurs d’agents pathogènes dans les marchés de la ville de Lomé. Des mesures d’hygiène doivent donc être renforcées dans ces marchés pour éviter la transmission croisée des agents pathogènes à l’homme.Mots clés: Musca domestica, Chrysomya chloropyga, bactéries, moisissures, marchésEnglish Title: Associated bacteria and fungi to Musca domestica L. and Chrysomya chloropyga Wied. (Diptera: Muscomorpha) collected from two differents environments of Lomé CityEnglish AbstractObjective: The objective of this study was to isolate and identify bacteria and fungi on the external surfaces of adult house fly Musca domestica L. and the blow fly Chrysomya chloropyga Wied, two species of synantropic fly who are abundance in the market of the city of Lomé.Methodogy and results: Both species were sampled from five market and botanical garden of city of Lomé. The conventional isolation of bacteria and fungi technique was used to research the microorganisms associated to both species of fly. Eleven bacteria species were isolated from 180 adult of each species of fly: Escherichia coli, Enterobacter agglomerans, Klebsiella spp, Proteus mirabilis, Proteus rettgeri, Proteus vulgaris, Proteus spp, Shigella spp, Staphylococcus aureus, negative coagulase Staphylococcus and Pseudomonas spp, and 2 fungi species : Aspergillus niger and Rhizopus spp in the market while in botanic garden, environment without food, only 3 species of bacteria (Proteus vulgaris, Proteus spp, Staphylococcus aureus) and fungi (Aspergillus niger, Rhizopus spp and Mucor spp) were identified.Conclusion and application: The diversity of the species of bacteria and fungi associated to fly sample in the market changed with the collecting sites and was linked with the hygienic quality of their environment. M. domestica and C. chloropyga have the potentiality to transmit the pathogens in the market of Lomé city. Sanitary action must be strengthen in the market to avoid the cross transmission of pathogen to human.Keywords: Musca domestica, Chrysomya chloropyga, bacteria, fungi, marke

Cotton pest management practices and the selection of pyrethroid resistance in Anopheles gambiae population in Northern Benin

<p>Abstract</p> <p>Background</p> <p>Pyrethroid insecticides, carbamate and organophosphate are the classes of insecticides commonly used in agriculture for crop protection in Benin. Pyrethroids remain the only class of insecticides recommended by the WHO for impregnation of bed nets. Unfortunately, the high level of pyrethroid resistance in <it>Anopheles gambiae </it>s.l., threatens to undermine the success of pyrethroid treated nets. This study focuses on the investigation of agricultural practices in cotton growing areas, and their direct impact on larval populations of <it>An. gambiae </it>in surrounding breeding sites.</p> <p>Methods</p> <p>The protocol was based on the collection of agro-sociological data where farmers were subjected to semi-structured questionnaires based on the strategies used for crop protection. This was complemented by bioassay tests to assess the susceptibility of malaria vectors to various insecticides. Molecular analysis was performed to characterize the resistance genes and the molecular forms of <it>An. gambiae</it>. Insecticide residues in soil samples from breeding sites were investigated to determine major factors that can inhibit the normal growth of mosquito larvae by exposing susceptible and resistant laboratory strains.</p> <p>Results</p> <p>There is a common use by local farmers of mineral fertilizer NPK at 200 kg/ha and urea at 50 kg/hectare following insecticide treatments in both the Calendar Control Program (CCP) and the Targeted Intermittent Control Program (TICP). By contrast, no chemicals are involved in Biological Program (BP) where farmers use organic and natural fertilizers which include animal excreta.</p> <p>Susceptibility test results confirmed a high resistance to DDT. Mean mortality of <it>An. gambiae </it>collected from the farms practicing CCP, TICP and BP methods were 33%, 42% and 65% respectively. <it>An. gambiae </it>populations from areas using the CCP and TICP programs showed resistance to permethrin with mortality of 50% and 58% respectively. By contrast, bioassay test results of <it>An. gambiae </it>from BP areas gave a high level of susceptibility to permethrin with an average mortality of 94%.</p> <p>Molecular analysis identified <it>An. gambiae </it>s.s, and <it>An. arabiensis </it>with a high predominance of <it>An. gambiae s.s </it>(90%). The two molecular forms, M and S, were also determined with a high frequency of the S form (96%).</p> <p>The <it>Kdr </it>gene seemed the main target- site resistance mechanism detected in CCP, TICP, and BP areas at the rates ranging from 32 to 78%. The frequency of <it>ace-1R </it>gene was very low (< 0.1).</p> <p>The presence of inhibiting factors in soil samples under insecticide treatments were found and affected negatively in delaying the development of <it>An. gambiae </it>larval populations.</p> <p>Conclusions</p> <p>This research shows that <it>Kdr </it>has spread widely in <it>An. gambiae</it>, mainly in CCP and TICP areas where pyrethroids are extensively used. To reduce the negative impact of pesticides use in cotton crop protection, the application of BP-like programs, which do not appear to select for vector resistance would be useful. These results could serve as scientific evidence of the spread of resistance due to a massive agricultural use of insecticides and contribute to the management of pesticides usage on cotton crops hence reducing the selection pressure of insecticides on <it>An. gambiae </it>populations.</p

Efficacy of two PBO long lasting insecticidal nets against natural populations of Anopheles gambiae s.l. in experimental huts, Kolokopé, Togo.

LLINs containing an insecticide plus the synergist, piperonyl butoxide (PBO) have been designed for increased efficacy against pyrethroid-resistant malaria vectors. In this study, two LLINs with PBO, PermaNet® 3.0 and Olyset® Plus, and a pyrethroid-only LLIN, Yorkool®, were evaluated in experimental huts against a free-flying, wild population of Anopheles gambiae s.l. in Kolokopé, a cotton cultivated area of Togo. WHO susceptibility tube tests and subsequent molecular assays determine the An. gambiae s.l. populations to be resistant to pyrethroids and DDT with both target site kdr and metabolic resistance mechanisms involved in the resistance observed. Anopheles gambiae s.s. and An. coluzzi were present in sympatry though the kdr (L1014F) mutation was observed at a higher frequency in An. gambiae s.s. The experimental hut results showed that both PermaNet® 3.0 and Olyset® Plus nets induced similar levels of deterrence, exophily, and reduced blood feeding rate against wild An. gambiae s.l. in contrast to the pyrethroid only LLIN, Yorkool®. The proportion of wild An. gambiae s.l. killed by unwashed PermaNet® 3.0 was significantly higher than unwashed Olyset® Plus (corrected mortality 80.5% compared to 66.6%). Similar blood feeding inhibition rates were observed for unwashed PermaNet® 3.0 and Olyset® Plus; however, PermaNet® 3.0 washed 20 times demonstrated significantly higher blood feeding inhibition rate than Olyset® Plus washed 20 times (91.1% compared with 85.6% respectively). Yorkool® performed the worst for all the parameters evaluated. In an area of pyrethroid resistance of An. gambiae s.l involving kdr target site and metabolic resistance mechanisms, LLINs with PBO can provide additional protection in terms of reduction in blood feeding and increase in mosquito mortality compared to a pyrethroid-only net, and should be considered in malaria vector control strategies

Characterization of the <i>An</i>. <i>gambiae s</i>.<i>l</i>. mosquito populations from Kolokopé.

<p>Characterization of the <i>An</i>. <i>gambiae s</i>.<i>l</i>. mosquito populations from Kolokopé.</p

WHO cone bioassay against susceptible <i>An</i>. <i>gambiae s</i>.<i>s</i>. Kisumu of nets before and after washing, and after the hut trial.

<p>WHO cone bioassay against susceptible <i>An</i>. <i>gambiae s</i>.<i>s</i>. Kisumu of nets before and after washing, and after the hut trial.</p

Active ingredient and synergist contents of each net sample before and after the experimental hut trial.

<p>Active ingredient and synergist contents of each net sample before and after the experimental hut trial.</p

WHO cone bioassay against wild resistant <i>An</i>. <i>gambiae s</i>.<i>l</i>. Kolokopé of all treatment arms before and after the hut trial.

<p>WHO cone bioassay against wild resistant <i>An</i>. <i>gambiae s</i>.<i>l</i>. Kolokopé of all treatment arms before and after the hut trial.</p

Summary of trial results obtained for free flying <i>An</i>. <i>gambiae s</i>.<i>l</i>. in experimental huts (98 nights) in Kolokopé, Togo.

<p>Summary of trial results obtained for free flying <i>An</i>. <i>gambiae s</i>.<i>l</i>. in experimental huts (98 nights) in Kolokopé, Togo.</p