Dengue is a tropical disease caused by an arbovirus transmitted by Aedes aegypti. Since no effective vaccine is available for treating dengue, the present study focused on population vector control through investigating the use of the lignan grandisin, isolated from Piper solmsianum C. DC., Piperaceae, against the larvae of A. aegypti. Grandisin caused larval (L3) mortality at LC50 150 µg/mL. Histological analysis on A. aegypti larvae treated with grandisin (LC50 50 µg/mL) showed changes in the anterior-middle midgut, with intense tissue destruction and cell disorganization.

O hábito alimentar dos culicídeos foi estudado através da técnica de precipitina. As coletas foram realizadas no km 52 da rodovia Transpantaneira (MT-060), a 65km da sede do município de Poconé (MT). Bimestralmente, de dezembro de 2002 a dezembro de 2003, foram realizadas capturas em armadilha Shannon e CDC automática à base de CO2 das 15:00h às 21:00h. Foram utilizados os seguintes anti-soros: ave, roedor, humano, cavalo, boi, capivara e sapo. Das 2.134 fêmeas capturadas, 1.946 (92,2%) foram coletadas em armadilha de Shannon e 188 (8,8%) em armadilha CDC. Desse total, 276 fêmeas (13,0%) estavam ingurgitadas e próprias para o teste de precipitina, sendo 235 (85,1%) coletadas em armadilha de Shannon e 41 (14,9%) em CDC. Verificou-se que 84,2% dos espécimes analisados reagiram para uma fonte alimentar e 15,8% para duas fontes. As espécies Mansonia titillans (Walker), Culex nigripalpus (Theobald), Aedeomyia squamipennis (Theobald) e Psorophora albigenu (Peryassu) foram as mais freqüentes e reagiram para todos os anti-soros. Os anofelinos Anopheles albitarsis (Lynch-Arribalzaga), An. matogrossensis (Lutz & Neiva) e An. triannulatus (Neiva & Pinto), com poucos espécimes, reagiram para cinco anti-soros. As demais espécies apresentaram positividade que variou de três a seis anti-soros. As estimativas do índice alimentar (feeding index) revelaram resultados positivos para oito espécies de culicídeos, destas cinco apresentaram preferência marcante para o hospedeiro capivara.

The feeding habits of culicids were studied by means of the precipitin technique. The collections were made the Trans-Pantanal highway (MT-060- km 52), at 65 km from the main settlement of the municipality of Poconé, MT, every other month, from December 2002 to December 2003. Trapping was performed using Shannon traps and CDC automatic CO2-based traps from 3:00 p.m. to 9:00 p.m. The following antisera were utilized: bird, rodent, human, horse, cattle, capybara and toad. Of the 2,134 females captured, 1,946 (92,2%) were collected in Shannon traps and 188 (8,8%) in CDC traps. Among these totals, 276 females (13,0%) were engorged and suitable for the precipitin test, of which 235 (85,1%) were collected in Shannon traps and 41 (14,9%) in CDC traps. It was found that 84.2% of the specimens analyzed reacted to one food source and 15.8% to two sources. Mansonia titillans (Walker), Culex nigripalpus (Theobald), Aedeomyia squamipennis (Lynch-Arribalzaga) and Psorophora albigenu (Peryassu) were the most frequently found species, and reacted to all the antisera. On the other hand, few specimens of the anophelines, Anopheles albitarsis (Lynch-Arribalzaga), An. matogrossensis (Lutz & Neiva) and An. triannulatus (Neiva & Pinto), reacted to five antisera. The other species were positive to three up to six antisera. The estimate of the feeding index revealed positive results for eight species, of these five they presented outstanding preference for the host capybara.