Effect of temperature and vector nutrition on the development and multiplication of Trypanosoma rangeli in Rhodnius prolixus
Trypanosoma rangeli is a protozoan parasite that infects mammals and triatomines, causing different levels of pathogenicity in its invertebrate vectors, particularly those from the genus Rhodnius. We have recently shown that temperature can modulate T. rangeli growth during in vitro culture, as well as its in vivo pathogenicity to R. prolixus. In the present study, we investigated colonization of R. prolixus by T. rangeli and assessed the role of temperature and vector nutrition on parasite development and multiplication. We infected nymphs and either assessed parasite density in the first hours after the ingestion of the infected blood or maintained the nymphs for up to 60 days at different temperatures (21, 24, 27, and 30 °C) and under different blood-feeding schedules (either every 15 days, or on day 30 post infection only), with parasite development and multiplication measured on days 15, 30, and 60 post infection. In the first hours after ingesting infected blood, epimastigogenesis not only occurred in the anterior midgut, but a stable parasite population also established in this intestinal region. T. rangeli subsequently colonized all intestinal regions examined, but with fewer parasites being found in the rectum. The number of parasites was only affected by higher temperatures (27 and 30 °C) during the beginning of the infection (15 days post infection). Nutritional status of the vector also had a significant effect on parasite development, as reduced blood-feeding decreased infection rates by approximately 30%.
KeywordsTrypanosoma rangeli Rhodnius prolixus Parasite-vector interaction Temperature Parasite growth
AAG was supported by CNPq productivity grants. This work received financial support from Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM/CNPq), and Programa Estratégico de Apoio a Pesquisa em Saúde (PAPES VI/FIOCRUZ).
Compliance with ethical standards
All protocols involving animals followed established procedures of Fiocruz and were approved by the Ethics Committee on Animal Use (CEUA-FIOCRUZ) under the license number LW 61/12.
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