Infecção experimental de Rhodnius robustus Larrousse, 1927 (Hemiptera, Reduviidae, Triatominae) por Trypanosoma cruzi Chagas, 1909 (Kinetoplastida, Trypanosomatidae) IV

• Autor(a) principal: Abreu, Ana Paula de
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/2059
• topic: Doença de Chagas; Trypanosoma cruzi; Infecção; Rhodnius robustus Larrousse; Suscetibilidade e capacidade vetorial; Brasil.; Rhodnius robustus; T; cruzi IV; Susceptibility and vectorial competence; Brazil.; Ciências da Saúde; Medicina

Most triatomine species may be natural or experimentally infected with Trypanosoma cruzi, the etiological agent of Chagas disease. However, the vectorial competence of triatomines for T. cruzi transmission depends on the interaction of the parasite-vector and the constitution of the parasite. Rhodnius robustus and R. brethesi have been frequently found harboring T. cruzi I and T. cruzi IV in the Brazilian Amazon and R. pictipes and R. pallescens (Colombia) only T. cruzi I. The aim of this study was to evaluate the susceptibility and vectorial competence of T. cruzi IV in experimentally infected Rhodnius robustus. Nymphs of the 3rd and 5th stages fed with mouse blood containing culture-derived metacyclic trypomastigotes (CMT) or blood trypomastigotes (BT), in artificial feeder (BTX) or in mice (BTM). After feeding on uninfected mice, every 20 days, insect excreta were examined by fresh examination and by the global counting in the Neubauer chamber, to evaluate vector competence. Every 30 days of infection (dai), a pool of intestinal contents (IC) obtained by dissecting two exemplar of each group was also examined to determine susceptibility to infection. Differential counts in excreta and IC were performed to determine the rate of metacyclogenesis. Fifth stage nymphs fed with CMT (CMT2 group) ingested a larger blood volume (mean of 74.5 uL) and greater amount of parasite forms (mean 149.000 CMT/μL). Nymphs of the 3rd stage (CMT1 group) presented higher positivity (33.3%) in the fresh examination of excreta and the CMT2 group in the intestinal contents, followed by the BTM group (25.0%). Metacyclic trypomastigote forms predominated in the excreta of insects of 3/4 experimental groups (CMT1, CMT2 and BTX) as early as 20 days after infection (dai) and were visualized in the intestinal contents of all experimental groups at 30 dai. Higher percentages of metacyclic trypomastigotes were observed in the excreta of the CMT2 group (84.1%) and in the intestinal contents of CMT1 (80.0%). R. robustus showed high susceptibility to TcIV, since ninphs of all stage became infected with culture or blood trypomastigotes. regardless of the method used for blood repellent. R. robustus demonstrated vectorial competence for TcIV, since high rates of metacyclogenesis (84.1 and 80.0%) were observed in excreta and in IC.