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International audience; Mosquito control is implemented when arboviruses are detected in patients or in field-collected mosquitoes. However, mass screening of mosquitoes is usually laborious and expensive, requiring specialized expertise and equipment. Detection of virus in mosquito saliva using honey-impregnated filter papers seems to be a promising method as it is non-destructive and allows monitoring the viral excretion dynamics over time from the same mosquito. Here we test the use of filter papers to detect chikungunya virus in mosquito saliva in laboratory conditions, before proposing this method in large-scale mosquito surveillance programs. We found that 0.9 cm 2 cards impregnated with a 50% honey solution could replace the forced salivation technique as they offered a viral RNA detection until 7 days after oral infection of Aedes aegypti and Aedes albopictus mosquitoes with CHIKV.

Background Reduced susceptibility of mosquito vectors to currently used insecticides hampers control interventions. Recently pyriproxyfen, an insect growth regulator has been demonstrated to effectively reduce the reproductive potential in vector mosquitoes. Methods Pyriproxyfen (PPF), in different concentrations (0.75%, 0.075%, 0.0075%, and 0.00075%) was applied on papers and Indian wild type Aedes aegypti female mosquitoes (N ≥ 20 for each treatment) were exposed onto it as per WHO guidelines, to study the reproductive disruption. PPF concentration on treated papers was quantitatively cross-determined using HPLC method. Reduction in fecundity, fertility and adult emergence in exposed female Ae. aegypti was determined. Abnormal development in ovary and eggs of exposed females was studied microscopically after different time intervals. Results Eggs laid, eggs hatched, pupae formed and adults emerged per female exposed in both before blood meal and after blood meal groups declined significantly from lowest to highest concentration of PPF (F ≥ 5.2; p < 0.02). Adult emergence inhibition in females exposed to PPF before and after blood meal groups ranged from 58.8% [OR = 0.18 (95% CI = 0.09–0.36)] to 79.2% [OR = 0.04 (95% CI = 0.02–0.10)] and 64.4% [OR = 0.12 (95% CI = 0.05–0.28)] to 77.1% [OR = 0.05 (95% CI = 0.02–0.14)] respectively in different concentrations. The probit model used suggested that FI50 (50% fertility inhibition) and EI50 (50% emergence inhibition) were 0.002% (p = 0.82) and 0.0001% (p = 0.99) for females exposed before blood meal, while 0.01% (p = 0.63) and, Author summary Development of resistance against insecticides has challenged mosquito control programmes globally and prompted the research of alternative options that can complement insecticides. An insect growth regulator, pyriproxyfen (PPF) usage against mosquitoes can effectively reduce the vector population. PPF mainly inhibits the metamorphosis of mosquito larvae into pupae and prevent the adult emergence, therefore it is generally applied in mosquito breeding habitats. PPF has been shown to exhibit delayed residual effect that may impair the reproductive capacity by affecting the survival, fecundity and fertility of adult mosquito exposed through tarsal contact. Presently, the effectiveness of different concentrations of PPF intended to be delivered through contact have been evaluated against dengue vector Ae. aegypti. Results suggested that very low PPF concentration treated surfaces drastically reduce the fecundity, fertility and adult emergence in mosquitoes. Study suggests that control interventions based on PPF-treated surfaces could provide an additional route to target mosquito vector control by overall population density reduction.

International audience; Background: Identification of the source of mosquito blood meals is an important component for disease control and surveillance. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling has emerged as an effective tool for mosquito blood meal identification, using the abdomens of freshly engorged mosquitoes. In the field, mosquito abdomens are crushed on Whatman filter papers to determine the host feeding patterns by identifying the origin of their blood meals. The aim of this study was to test whether crushing engorged mosquito abdomens on Whatman filter papers was compatible with MALDI-TOF MS for mosquito blood meal identification. Both laboratory reared and field collected mosquitoes were tested.Material and methods: Sixty Anopheles gambiae Giles were experimentally engorged on the blood of six distinct vertebrate hosts (human, sheep, rabbit, dog, chicken and rat). The engorged mosquito abdomens were crushed on Whatman filter papers for MALDI-TOF MS analysis. 150 Whatman filter papers, with mosquitoes engorged on cow and goat blood, were preserved. A total of 77 engorged mosquito abdomens collected in the Comoros Islands and crushed on Whatman filter papers were tested with MALDI-TOF MS. Results The MS profiles generated from mosquito engorged abdomens crushed on Whatman filter papers exhibited high reproducibility according to the original host blood. The blood meal host was correctly identified from mosquito abdomens crushed on Whatman filter papers by MALDI-TOF MS. The MS spectra obtained after storage were stable regardless of the room temperature and whether or not they were frozen. The MS profiles were reproducible for up to three months. For the Comoros samples, 70/77 quality MS spectra were obtained and matched with human blood spectra. This was confirmed by molecular tools.Conclusion: The results demonstrated that MALDI-TOF MS could identify mosquito blood meals from Whatman filter papers collected in the field during entomological surveys. The application of MALDI-TOF MS has proved to be rapid and successful, making it a new and efficient tool for mosquito-borne disease surveillance.