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The Zika virus is a flavivirus spread by the Aedes aegypti mosquito, which also transmits dengue and chikungunya. Current forms of control include elimination of mosquito breeding sites, use of insecticides, repellents and other means. The present study developed new adsorbent materials based on silica and biomaterials capable of releasing an Aedes aegypti mosquito repellent. The materials synthesized were characterized by Fourier-Transform Infrared, thermogravimetric analysis, Scanning Electron Microscopy and Brunauer, Emmett and Teller analysis and tested with citronella, an essential oil widely recognized as a natural insect repellent. The materials presented type IV isotherms, with type H1 hysteresis, characteristic of mesoporous materials, with pore diameters of between 50 Å and 80 Å. Materials based on silica-chitosan-glutaraldehyde dried in an oven (SCGO) and silica-chitosan-glutaraldehyde dried under a vacuum (SCGV) were found to produce more controlled release of citronella essential oil. The bioassay test was performed using a horizontal double-choice olfactometer. The adsorbent SCGO remained stable for the four hours of the bioassay, while the commercial repellent became ineffective after two hours of release. The production of a prototype in the form of bracelets, stickers releasing a volatile repellent is therefore proposed as a method for the control of the mosquito in urban areas.

This study investigated the biological activities of five benthic marine algae collected from Northeastern Region of Brazil. The tested activities included larvicidal activity against Aedes aegypti, molluscicidal activity against Biomphalaria glabrata, and toxicity against Artemia salina. Extracts of Ulva lactuca (Chlorophyta), Padina gymnospora, Sargassum vulgare (Phaeophyta), Hypnea musciformis, and Digenea simplex (Rhodophyta) were prepared using different solvents of increasing polarity, including dichloromethane, methanol, ethanol, and water. Of the extracts screened, the dichloromethane extracts of H. musciformis and P. gymnospora exhibited the highest activities and were subjected to bioassay-guided fractionation in hexane and chloroform. The chloroform fractions of the P. gymnospora and H. musciformis extracts showed molluscicidal activity at values below 40 μg·mL−1 (11.1460 μg·mL−1 and 25.8689 μg·mL−1, resp.), and the chloroform and hexane fractions of P. gymnospora showed larvicidal activity at values below 40 μg·mL−1 (29.018 μg·mL−1 and 17.230 μg·mL−1, resp.). The crude extracts were not toxic to A. salina, whereas the chloroform and hexane fractions of P. gymnospora (788.277 μg·mL−1 and 706.990 μg·mL−1) showed moderate toxicity, indicating that the toxic compounds present in these algae are nonpolar.