Therapeutic effects of benznidazole in Swiss mice that are orally inoculated with Trypanosoma cruzi IV strains from the Western Brazilian Amazon

Teston, Ana Paula Margioto; Fernandes, Nilma de Souza; Abegg, Camila Piva; Abreu, Ana Paula de; Sarto, Marcella Paula Mansano; Gomes, Mônica Lúcia; Toledo, Max Jean de Ornelas

doi:10.1016/j.exppara.2021.108136

Cited by 4 publications

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“…In pure infections, the maximum peak of parasitemia occurs on the seventh day post-infection (dpi) for strains AM33 (TcIAM) and AM14 (TcIVAM), and on the 13th dpi for strains PR150 (TcIMG) and PR1256 (TcIIPR). In mixed infections (TcIAM+TcIIPR, TcIAM+TcIVAM, TcIMG+TcIIPR, TcIMG+TcIVAM and TcIIPR+TcIVAM), the insects were fed both on the seventh and 13th dpi, according to the parasitemia curve profiles of each strain, which our group has previously described [ 33 , 37 , 38 ]. At the peak of parasitemia, the mice had approximately 1400 blood trypomastigotes (BT) per 0.1 ml of blood [ 37 , 39 ], both for the pure infections with one strain (TcIAM, TcIMG, TcIIPR or TcIVAM) and for the mixed infections containing two strains (TcIAM+TcIIPR, TcIAM+TcIVAM, TcIMG+TcIIPR, TcIMG+TcIVAM and TcII+TcIVAM).…”

Section: Methodsmentioning

confidence: 99%

Infection susceptibility and vector competence of Rhodnius robustus Larrousse, 1927 and R. pictipes Stal, 1872 (Hemiptera, Reduviidae, Triatominae) for strains of Trypanosoma cruzi (Chagas, 1909) (Kinetoplastida, Trypanosomatidae) I, II and IV

et al. 2022

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Background Rhodnius robustus and Rhodnius pictipes are vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease (CD), that are found in the Brazilian Amazon region. Susceptibility to infection and vector competence depend on the parasite-vector relationship. Our objective was to evaluate the interaction between T. cruzi and these two triatomine vectors in pure and mixed experimental infections of T. cruzi strains from the same or different geographic regions. Methods Fifth-instar nymphs of R. robustus and R. pictipes were fed on mice infected with four T. cruzi strains, namely genotypes TcIAM, TcIMG, TcIIPR, and TcIVAM, respectively, from the Brazilian states of Amazonas, Minas Gerais and Paraná. Over a period of 120 days, excreta were examined every 20 days to assess vector competence, and intestinal contents (IC) were examined every 30 days to determine susceptibility to infection. Results The highest positive rate in the fresh examination (%+FE, 30.0%), the highest number of parasitic forms (PF, n = 1969) and the highest metacyclogenesis rate (%MC, 53.8%) in the excreta were recorded for R. robustus/TcIVAM. Examination of the IC of R. pictipes revealed a higher number of PF in infections with TcIAM (22,680 PF) and TcIIPR (19,845 PF) alone or in association (17,145 PF), as well as a %+FE of 75.0% with TcII, in comparison with the other genotypes. The highest %MC (100%) was recorded for the mixed infections of TcIAM with TcIIPR or TcIVAM in the IC of R. pictipes. Conclusions Overall, both species were found to be susceptible to the T. cruzi strains studied. Rhodnius robustus showed vector competence for genotypes TcIVAM and TcIAM+TcIVAM and R. pictipes for TcIAM+TcIVAM and TcIAM+TcIIPR; there was elimination of infective forms as early as at 20 days. Our results suggest that both the genetics of the parasite and its geographic origin influence the susceptibility to infection and vector competence, alone or in association. Graphical Abstract

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