scholarly journals Trypanosoma cruzi-infected Rhodnius prolixus endure increased predation facilitating parasite transmission to mammal hosts

2021 ◽  
Vol 15 (7) ◽  
pp. e0009570
Author(s):  
Newmar Pinto Marliére ◽  
Marcelo Gustavo Lorenzo ◽  
Alessandra Aparecida Guarneri
Keyword(s):  
Trypanosoma Cruzi ◽  
Effective Means ◽  
Rhodnius Prolixus ◽  
Parasite Transmission ◽  
Intermediate Hosts ◽  
Oral Transmission ◽  
Vector Interaction ◽  
Triatomine Bugs ◽  
Increased Risk ◽  
Predation Rates

Triatomine bugs aggregate with conspecifics inside shelters during daylight hours. At dusk, they leave their refuges searching for hosts on which to blood feed. After finding a host, triatomines face the threat of being killed, because hosts often prey on them. As it is known that many parasites induce the predation of intermediate hosts to promote transmission, and that ingestion of Trypanosoma cruzi-infected bugs represents a very effective means for mammal infection, we hypothesized that trypanosomes induce infected bugs to take increased risk, and, as a consequence, be predated when approaching a host. Therefore, we evaluated whether the predation risk and predation rates endured by Rhodnius prolixus increase when infected with T. cruzi. Assays were performed in square glass arenas offering one central refuge to infected and uninfected 5th instar nymphs. A caged mouse was introduced in each arena after a three-day acclimation interval to activate sheltered insects and induce them to approach it. As hypothesized, a significantly higher proportion of infected insects was predated when compared with uninfected ones (36% and 19%, respectively). Indeed, T. cruzi-infected bugs took higher risk (Approximation Index = 0.642) when compared with healthy ones (Approximation Index = 0.302) and remained outside the shelters when the host was removed from the arena. Our results show that infection by T. cruzi induces bugs to assume higher risk and endure higher predation rates. We reveal a hitherto unknown trypanosome-vector interaction process that increases infected bug predation, promoting increased rates of robust oral transmission. The significant consequences of the mechanism revealed here make it a fundamental component for the resilient maintenance of sylvatic, peridomestic and domestic cycles.

scholarly journals Distribution and natural infection status of synantrophic triatomines (Hemiptera: Reduviidae), vectors of Trypanosoma cruzi, reveals new epidemiological scenarios for chagas disease in the Highlands of Colombia

2021 ◽  
Vol 15 (7) ◽  
pp. e0009574
Author(s):  
Omar Cantillo-Barraza ◽  
Manuel Medina ◽  
Sara Zuluaga ◽  
María Isabel Blanco ◽  
Rodrigo Caro ◽  
...  
Keyword(s):  
Spatial Analysis ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Natural Infection ◽  
Significant Risk ◽  
Rhodnius Prolixus ◽  
The Other ◽  
Infection Status ◽  
Triatomine Bugs ◽  
Increased Risk

Introduction Updating the distribution and natural infection status of triatomine bugs is critical for planning, prioritizing, and implementing strategies to control Chagas disease (CD), especially after vector reduction programs. After carrying out a control program, the Department of Boyaca contains the highest number of Colombian municipalities certified by PAHO to be free of intradomiciliary transmission of Trypanosoma cruzi by Rhodnius prolixus. The present work describes the spatial distribution, natural infection (NI), and molecular characterization of T. cruzi in synanthropic triatomines from the Department of Boyaca in 2017 and 2018. Materials and methods An entomological survey was conducted in 52 municipalities in Boyaca known to have had previous infestations of triatomine bugs. Insects were collected through active searches carried out by technical personnel from the Secretary of Health and community members using Triatomine Collection Stations (PITs-acronym in Spanish). For evaluation of natural infection, triatomines were identified morphologically and grouped in pools of one to five individuals of the same species collected in the same household. DNA derived from the feces of each pool of insects was analyzed by PCR for the presence of T. cruzi using primers flanking the satellite DNA of the parasite. SL-IR primers were used to differentiate TCI from the other DTUs and to identify different genotypes. The distribution of the collected triatomines was analyzed to determine any vector hotspots using spatial recreation. Results A total of 670 triatomine bugs was collected, belonging to five species: Triatoma dimidiata (73.2%), Triatoma venosa (16.7%), Panstrongylus geniculatus (5.7%), Rhodnius prolixus (4.4%), and Panstrongylus rufotuberculatus (0.4%), from 29 of the 52 municipalities. In total, 71.6% of the bugs were collected within houses (intradomiciliary) and the rest around the houses (peridomiciliary). Triatoma dimidiata was the most widely distributed species and had the highest natural infection index (37.8%), followed by T. venosa and P. geniculatus. TcI was the only DTU found, with the TcI Dom genotype identified in 80% of positive samples and TcI sylvatic in the other insects. Spatial analysis showed clusters of T. dimidiata and T. venosa in the northeast and southwest regions of Boyaca. Conclusions After some municipalities were certified free of natural transmission within houses (intradomiciliary transmission) of T. cruzi by R. prolixus, T. dimidiata has become the most prevalent vector present, and represents a significant risk of resurgent CD transmission. However, T. venosa, P. geniculatus, and P. rufotuberculatus also contribute to the increased risk of transmission. The presence of residual R. prolixus may undo the successes achieved through vector elimination programs. The molecular and spatial analysis used here allows us to identify areas with an ongoing threat of parasite transmission and improve entomological surveillance strategies.

scholarly journals Participation of Trypanosoma cruzi gp63 molecules on the interaction with Rhodnius prolixus

Parasitology ◽  
2019 ◽  
Vol 146 (8) ◽  
pp. 1075-1082 ◽  
Author(s):  
Karina M. Rebello ◽  
Livia A. Uehara ◽  
Vítor Ennes-Vidal ◽  
Aline S. Garcia-Gomes ◽  
Constança Britto ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Rhodnius Prolixus ◽  
Mammalian Host ◽  
Insect Vector ◽  
Metal Chelators ◽  
Insect Midgut ◽  
Host Interaction ◽  
Vector Interaction ◽  
Vector Borne ◽  
First Time

AbstractTrypanosoma cruzi is the causative agent of Chagas disease, a vector-borne disease. The parasite molecules involved in vector interaction have been little investigated. Metallopeptidases and gp63 molecules have been implicated in parasite adhesion of several trypanosomatids to the insect midgut. Although gp63 homologues are highly expanded in the T. cruzi genome, and are implicated in parasite–mammalian host interaction, its role in the insect vector has never been explored. Here, we showed that divalent metal chelators or anti-Tcgp63-I antibodies impaired T. cruzi adhesion to Rhodnius prolixus midgut. Parasites isolated after insect colonization presented a drastic enhancement in the expression of Tcgp63-I. These data highlight, for the first time, that Tcgp63-I and Zn-dependent enzymes contribute to the interaction of T. cruzi with the insect vector.

scholarly journals The smORF-containing gene mille-pattes is required for moulting and Trypanosoma cruzi metacyclogenesis in the Chagas disease vector Rhodnius prolixus

2020 ◽  
Author(s):  
Carina Azevedo ◽  
Bruno Rodrigues ◽  
Sandy Alves ◽  
Lupis Ribeiro ◽  
Carlos Logullo ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Disease Transmission ◽  
Postembryonic Development ◽  
Rhodnius Prolixus ◽  
Open Reading Frames ◽  
Disease Spread ◽  
Polished Rice ◽  
Triatomine Bugs ◽  
Small Open Reading Frames

SummaryChagas disease is estimated to affect 8 million people worldwide and is responsible for approximately 10,000 deaths in Latin America every year. Control of the triatomine bugs that transmit the flagellated parasite Trypanosoma cruzi has been the most successful strategy to avoid disease spread. Genes containing small open reading frames (smORFs, < 100 amino acids) constitute a putative reservoir of new vector control targets, since hundreds of these genes are present in insect genomes. Here, we show that the prototypic smORF-containing gene mille-pattes/polished-rice/tarsalless (mlpt/pri/tal) is essential for postembryonic development of the kissing bug Rhodnius prolixus and for T. cruzi metacyclogenesis during the nymphal stages. Injection of double-stranded RNA against mlpt (Rp-dsmlpt) during the nymphal stages leads to a plethora of phenotypes, which impair postembryonic development. First, fourth or fifth stage nymphs injected with Rp-dsmlpt do not moult even in the presence of the ecdysone receptor (EcR) mRNA. Second, Rp-dsmlpt nymphs have defects in gut morphology, delayed haemoglobin digestion, and decreased defecation volume compared with those of the control nymphs. Third, Rp-mlpt knockdown inhibits T. cruzi differentiation to the trypomastigote infective stage (metacyclogenesis) inside the R. prolixus gut. Overall, our study is the first to provide evidence that a smORF-containing gene regulates vector physiology and parasitic cycle thus enabling the development of novel molecular strategies to eliminate Chagas disease transmission.

scholarly journals Evaluation of the in vitro trypanocidal activity of triterpenes uvaol, betulinic acid and its semi-synthetic derivatives against the Y strain of Trypanosoma cruzi / Avaliação da atividade tripanocida in vitro dos triterpenos uvaol, ácido betulínico e seus derivados semissintéticos contra a cepa Y de Trypanosoma cruzi

2021 ◽  
Vol 7 (9) ◽  
pp. 90504-90517
Author(s):  
Moisés Soares Moreira Júnior ◽  
Lúzio Gabriel Bocalon Flauzino ◽  
Maria Gabriela Marçal ◽  
Daniele da Silva Ferreira ◽  
Patrícia Mendonça Pauletti ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Betulinic Acid ◽  
In Vitro Tests ◽  
Oral Transmission ◽  
A Value ◽  
Triatomine Bugs ◽  
Ic50 Value ◽  
Synthetic Derivatives

Chagas disease is a neglected tropical disease that affects millions of people worldwide. Trypanosoma cruzi (T. cruzi) is the causative agent of Chagas disease and its transmission occurs through blood meal by triatomine bugs, being oral transmission the most common form. More than 100 years after the disease´s discovery, benzonidazole is the only efficient drug against T. cruzi; however, this drug has numerous serious side effects and is only efficient in the acute phase of the disease. Natural products, such as triterpenes, have been an important source of new substances to combat human parasitology. In this study, two triterpenes, uvaol and betulinic acid, were tested against the parasite T. cruzi. The best results of in vitro tests were observed for uvaol with an IC50 value of 70.3 µM against the trypomastigost forms and an IC50 value of 90.6 µM against the amastigost forms. Three semi-synthetic derivatives of betulinic acid were obtained; the acetylated derivative showed excellent results against trypomastigotes forms (IC50 = 15.67 µM), but was not active against the amastigotes forms. The cytotoxic MTT test was also performed on LLCMK2 cells (Macaca mullata kidney epithelial cells) and betulinic acid showed the highest selectivity index (SI) with a value of 1.3.

scholarly journals A simple method to purify biologically and antigenically preserved bloodstream trypomastigotes of Trypanosoma cruzi using Deae-cellulose columns

1983 ◽  
Vol 78 (3) ◽  
pp. 317-333 ◽  
Author(s):  
Maria Auxiliadora de Sousa
Keyword(s):  
Trypanosoma Cruzi ◽  
Deae Cellulose ◽  
Mouse Blood ◽  
Simple Method ◽  
Infected Blood ◽  
Normal Morphology ◽  
Mean Survival Time ◽  
Triatomine Bugs ◽  
Forms Processing ◽  
Polymorphism Pattern

A method to purify trypanosomastigotes of some strains of Trypanosoma cruzi (Y, CL, FL, F, "Berenice", "Colombiana" and "São Felipe") from mouse blood by using DEAE-cellulose columns was standardized. This procedure is a modification of the Lanham & Godfrey methods and differs in some aspects from others described to purify T. cruzi bloodstream trypomastigotes, mainly by avoidance of prior purifications of parasites. By this method, the broad trypomastigotes were mainly isolated, accounting for higher recoveries obtained with strains having higher percentages of these forms: processing of infected blood from irradiated mice could be advantageous by increasing the recovery of parasites (percentage and/or total number) and elution of more slender trypomastigotes. Trypomastigotes purified by this method presented normal morphology and motility, remained infective to triatomine bugs and mice, showing in the latter prepatent periods and courses parasitemia similar to those of control parasites, and also reproducing the polymorphism pattern of each strain. Their virulence and pathogenicity also remained considerably preserved, the latter property being evaluated by LD 50 tests, mortality rates and mean survival time of inoculated mice. Moreover, these parasites presented positive, clear and peripheral immunofluorescence reaction at titres similar to those of control organisms, thus suggesting important preservation of their surface antigens.

An ecological overview on the factors that drives to Trypanosoma cruzi oral transmission

Acta Tropica ◽  
2015 ◽  
Vol 151 ◽  
pp. 94-102 ◽  
Author(s):  
Belkisyolé Alarcón de Noya ◽  
Oscar Noya González
Keyword(s):  
Trypanosoma Cruzi ◽  
Oral Transmission

Abstract 2851: Temporal QT Variability from Bipolar Ventricular Tip-to-Ring Electrograms Predicts Sustained Ventricular Tachyarrhythmia.

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Larisa G Tereshchenko ◽  
Barry J Fetics ◽  
Peter P Domitrovich ◽  
Ronald D Berger
Keyword(s):  
Risk Stratification ◽  
Right Ventricular ◽  
Effective Means ◽  
Ventricular Tachyarrhythmia ◽  
Icd Implantation ◽  
Area Index ◽  
Icd Therapy ◽  
Increased Risk ◽  
Qt Variability

We assessed the hypothesis that ventricular tachycardia / ventricular fibrillation (VT/VF) risk stratification based on the repolarization assessment of intracardiac electrograms (EGMs) from implantable devices is feasible. Methods: Bipolar right ventricular tip-to-ring EGMs were recorded at rest (mean heart rate 66 ± 16 bpm) for 5.5 ± 2.6 minutes in 75 patients (58 ± 14 years, 72% men) with ischemic (60%) and non-ischemic (40%) cardiomyopathy who underwent single-chamber Medtronic ICD implantation for primary (77%) or secondary (23%) prevention of SCD. QT variability index (QTVI), variability of Tpeak-Tend area index, and T-wave alternans (TWA) were calculated as previously described elsewhere. Only 41 out of 75 recordings (55%) were eligible for analysis as determined by data quality requirements of the custom software (less than 10% non-analyzable beats or 5% ectopic beats). The endpoint was appropriate ICD therapy for VT/VF during follow-up > 6 months. Results: During mean follow-up of 12 months (range 6–19 months), 12 patients had appropriate ICD therapy. The survival analysis showed that the top quartile of QTVI (> - 0.5) predicts an event-free survival rate from appropriate ICD therapies (p = 0.027). Neither increased Tpeak-Tend area variability nor TWA was associated with a significant increased risk for VT/VF. Conclusions: In this prospective study, temporal QT variability measured from right ventricular tip-to-ring EGMs is associated with increased risk of sustained VT/VF events. Repolarization lability may be present throughout the ventricular myocardium, such that single-site EGMs may provide an effective means for VT/VF risk stratification.

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