Dynamic development of Trypanosoma cruzi in Rhodnius prolixus : role of decapitation and ecdysone therapy

Abstract

Decapitation and ecdysone therapy on the population dynamics of the Trypanosoma cruzi Dm28c clone in the stomach, small intestine and rectum of fifth-instar larvae of Rhodnius prolixus were investigated. Parasites were not found in the small intestine and rectum of decapitated insects after 10 days post-infection (p.i.). Decapitated ecdysone-supplemented insects sustained the flagellate infection in both gut compartments. In the rectum, the population density of parasites increased 5-fold in ecdysone-treated decapitated larvae and 7-fold in control insects. Epimastigote forms dominated with 40-65%, intermediate stages and round forms varied over 10-35% in the stomach, small intestine and rectum in both insect groups. Low numbers of metacyclic trypomastigotes were observed in the stomach and small intestine of the control group and decapitated insects supplemented with ecdysone but, at 15 days p.i., this form of flagellate reached about 20% in the rectum of the control insects. In the entire gut, at 30 days p.i., 23% of parasites in the control group and 8% in the decapitated insects treated with ecdysone were found. These results indicate that a head factor, possibly the prothoracicotropic hormone from the brain which stimulates ecdysone production by the prothoracic glands, may act directly or indirectly to stimulate the development of epimastigotes and round forms of the parasite and that a single ecdysone treatment is not able to fully reverse metacyclogenesis in decapitated R. prolixus.

Monitoring of the Parasite Load in the Digestive Tract of Rhodnius prolixus by Combined qPCR Analysis and Imaging Techniques Provides New Insights into the Trypanosome Life Cycle

“…In addition, in contrast to our results, this method does not allow the detection of parasites in the AM at p.i. times beyond ten days [ 36 ] and misses parasites that adhere to insect tissue. This contrasts with our qPCR methodology, which allows the detection of up to 1 parasite/AM, two weeks after the refeeding of infected vectors with low level of parasites (~ 10 4 parasites) but also cell aggregates.…”

Trypanosoma cruzi TcSMUG L-surface Mucins Promote Development and Infectivity in the Triatomine Vector Rhodnius prolixus

“…At days 7, 14 or 21, the entire digestive tracts consisting of anterior midgut (stomach), posterior midgut and rectum of 10 insects were dissected and homogenized in a small volume of PBS. Afterwards, additional PBS was added to fill the homogenates to 1 ml [38] , [39] . The number of parasites in each homogenate was determined using a Neubauer hemocytometer [40] , [41] .…”

Gene annotation of nuclear receptor superfamily genes in the kissing bug Rhodnius prolixus and the effects of 20‐hydroxyecdysone on lipid metabolism

“…However, the amount of circulating ecdysone varies according to the circadian rhythm (Cardinal-Aucoin et al, 2013). 20-HE has several roles in R. prolixus, including neuropeptide production (Wulff et al, 2018), Trypanosoma cruzi development (Gonzalez et al, 1999;Cortez et al, 2002Cortez et al, , 2012, immune system modulation (Azambuja et al, 1997;Figueiredo et al, 2006;Genta et al, 2010) and structural changes in the gut (Garcia et al, 1998;Gonzalez et al, 1999;Albuquerque-Cunha et al, 2004).…”