scholarly journals Insecticidal efficacy of fluralaner (Bravecto®) against Triatoma brasiliensis, a major vector of Trypanosoma cruzi in Brazil

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Tamyres Bernadete Dantas Queiroga ◽  
Luanderson Cardoso Pereira Gomez ◽  
Eduardo Rodrigues de Sena ◽  
Wilo Victor dos Santos ◽  
Henrique Rafael Pontes Ferreira ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Blood Meal ◽  
Protozoan Parasite ◽  
Treated Group ◽  
Control Group ◽  
Vector Transmission ◽  
Control Center ◽  
Insecticidal Effect ◽  
Insecticidal Efficacy

Abstract Background Triatomines are responsible for the vector transmission of the protozoan parasite Trypanosoma cruzi, which causes Chagas disease. Triatoma brasiliensis is the main vector of the parasite in Brazil, and dogs are an important reservoir of the parasite. The aim of this study was to evaluate the insecticidal effect of fluralaner (Bravecto®) on T. brasiliensis after a blood meal in treated dogs. Methods Healthy mongrel dogs (n = 8) were recruited from the Zoonoses Control Center (ZCC) in the city of Natal, Rio Grande do Norte, Brazil, and randomized into two groups, a fluralaner (Bravecto®)-treated group (n = 4) and a control group (n = 4). Colony-reared third-, fourth- and fifth-instar nymphs of T. brasiliensis nymphs (n = 10) were allowed to feed on dogs from both groups for 30–40 min, once monthly, for up to 12 months. Bug mortality was observed up to 5 days after each blood meal. Results Mortality in triatomines which had a blood meal on fluralaner (Bravecto®)-treated dogs was 100% for up to 7 months after treatment, with mortality decreasing to 66.4% after 8 months, 57% after 9 months, 35% after 10 months, 10% after 11 months and 0% after 12 months. The mortality of triatomines that fed on non-treated control dogs was always ≤ 2.5%. Conclusions Our results suggest that fluralaner (Bravecto®) treatment of dogs induces long-term mortality of T. brasiliensis after the blood meal. This is a potential approach to be used to control vector transmission of T. cruzi, the etiological agent of Chagas disease, especially in endemic areas. Graphical Abstract

Temperature, Mitochondria, and Reye's Syndrome

PEDIATRICS ◽  
1983 ◽  
Vol 71 (6) ◽  
pp. 985-985
Author(s):  
RIF S. EL-MALLAKH
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Protozoan Parasite ◽  
Mitochondrial Enzyme ◽  
Reye's Syndrome ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
Mitochondrial Defect ◽  
Intracellular Protozoan Parasite

To the Editor.— Mitochondrial failure, manifest by changes in mitochondrial enzyme activity1-3 and morphology,4-5 is central to Reye's syndrome (RS).6 Although it has been variously hypothesized that the mitochondrial changes are secondary to an exogenous toxin,7-12 or an intrinsic mitochondrial defect,6 the actual cause remains obscure. Electron microscopic studies have shown sweelling and loss of cristate in mitochondria of patients with RS. It is interesting that very similar changes occur in Trypanosoma cruzi.13-16 T cruzi is an extracellular/intracellular protozoan parasite which causes Chagas' disease.17

scholarly journals Assessment of the insecticidal activity of oral afoxolaner against Phlebotomus perniciosus in dogs

Parasite ◽  
2019 ◽  
Vol 26 ◽  
pp. 63
Author(s):  
Nadège Perier ◽  
Wilfried Lebon ◽  
Leon Meyer ◽  
Noua Lekouch ◽  
Nesrine Aouiche ◽  
...  
Keyword(s):  
Untreated Control ◽  
Exposure Period ◽  
Blood Feeding ◽  
Treated Group ◽  
Control Group ◽  
Untreated Control Group ◽  
Phlebotomus Perniciosus ◽  
Post Exposure ◽  
Insecticidal Efficacy ◽  
Healthy Dogs

Twelve healthy dogs were included in this laboratory efficacy study. Six dogs were randomly allocated based on body weight to an untreated control group and six to an afoxolaner (NexGard®) treated group. In the treatment group, afoxolaner was administered orally on Day 0 in accordance with label instructions. On Days 1, 14 and 28, each dog was exposed to 60 unfed female and 10 male Phlebotomus perniciosus sandflies for 1 h. At the end of each exposure period, sandflies were counted and assessed for viability and feeding status. There was no statistical difference in mortality (0.0–5.4%), nor in feeding proportion (61.6–78%) between the control and the treated groups at all 1-h post-exposure assessments. After collection, live fed and unfed sandflies were kept for viability assessments at 48 and 72 h post-exposure. In the untreated control group, the average percentages of live, fed, female sandflies after exposure, on Days 1, 14 and 28, ranged from 51% to 74% at 48 h and from 46% to 57% at 72 h, demonstrating model robustness over the 28 days of the study. Significantly fewer live fed sandflies were recorded for the afoxolaner treated group (p < 0.01). The insecticidal efficacy was 100%, 95.9% and 75.2% at 48 h post Days 1, 14 and 28 exposures, respectively, and 100%, 100% and 86.3% at 72 h post Days 1, 14, and 28 exposures, respectively. A single administration of oral afoxolaner (NexGard®) to dogs significantly killed P. perniciosus sandflies 48 and 72 h after blood feeding for 1 month.

scholarly journals Effects of betamethasone on the course of experimentai. Infection with Trypanosoma cruzi

1986 ◽  
Vol 19 (3) ◽  
pp. 161-164 ◽  
Author(s):  
Frederico G.C. Abath ◽  
Yara M. Gomes ◽  
Eridan M. Coutinho ◽  
Silvia M.L. Montenegro ◽  
Maria E.B. Melo ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Acute Phase ◽  
Bacterial Infections ◽  
Acute Infection ◽  
Chronic Phase ◽  
Control Group ◽  
Cumulative Mortality ◽  
Histopathological Findings ◽  
Experimental Group

In this experiment, the effect of betamethasone administered in the early post- acute infection of mice by Trypanosoma cruzi was studied. This drug was administered during 30 days after the 42nd day of infection in a dose of 0.15 mg/day. The betamethasone treatment did not cause fresh outbreaks of parasitemia and the histopathological findings in the chronic phase were not different from those in the control group. The higher cumulative mortality after treatment in the experimental group was due to superimposed bacterial infections. Outbred albino mice infected with low numbers ofY strain Trypanosoma cruzi trypomastigotes were not suitable models for Chagas' disease, since after 7 months of observation only mild histological lesions developed in all the animais. Prolonged betamethasone treatment of mice infected with low numbers o/Trypanosoma cruzi of the Y strain, during the post-acute phase did not aggravate the course of infection.

Changes of RAPD profile of Trypanosoma cruzi II with Canova and Benznidazole

Homeopathy ◽  
2008 ◽  
Vol 97 (02) ◽  
pp. 59-64 ◽  
Author(s):  
Denise Lessa Aleixo ◽  
Fabiana Nabarro Ferraz ◽  
Carolina Sundin de Melo ◽  
Mônica Lúcia Gomes ◽  
Max Jean Toledo ◽  
...  
Keyword(s):  
Immune System ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Saline Solution ◽  
Polyacrylamide Gel ◽  
Control Group ◽  
Genetic Lineage ◽  
Rapd Profile ◽  
Random Amplification ◽  
Liver Infusion Tryptose

Chagas disease, caused by the protozoan Trypanosoma cruzi, involves immunomediated processes. Canova (CA) is a homeopathic treatment indicated in the diseases in which the immune system is depressed. This study evaluated the Random Amplification of Polymorphic DNA (RAPD) profile of T. cruzi under the influence of CA and Benznidazole (BZ). Mice infected with the genetic lineage of T. cruzi II (Y strain) were divided into 4 groups:Infected animals treated with saline solution (control group); treated with CA; treated with BZ; treated with CA and BZ combined.Treatment was given at the 5th–25th days of infection (D5–25). The parasites were isolated by haemoculture in Liver Infusion Tryptose (LIT) medium: at D5 (before treatment), D13, 15 and 25 (during treatment) and D55 and 295 (after treatment). DNA was extracted from the mass of parasites. RAPD was done with the primers λgt11-F, M13F-40 and L15996, the amplified products were eletrophoresed through a 4% polyacrylamide gel. Data were analyzed by the coefficient of similarity using the DNA-POP program.163 markers were identified, 5 of them monomorphic. CA did not act against the parasites when used alone. The RAPD profiles of parasites treated with BZ and CA + BZ were different from those in the control group and in the group treated with CA. The actions of the CA and BZ were different and the action of BZ was different from the action of CA + BZ. These data suggest that CA may interact with BZ. The differences in the RAPD profile of the Y strain of T. cruzi produced by BZ, CA + BZ and the natural course of the infection suggest selection/suppression of populations.

scholarly journals Dispersal patterns of Trypanosoma cruzi in Arequipa, Peru

2019 ◽  
Author(s):  
Alexander S.F. Berry ◽  
Renzo Salazar-Sánchez ◽  
Ricardo Castillo-Neyra ◽  
Katty Borrini-Mayorí ◽  
Claudia Arevalo-Nieto ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Causative Agent ◽  
Animal Movement ◽  
Protozoan Parasite ◽  
Domestic Animal ◽  
Urban Environments ◽  
Urban Landscapes ◽  
Population Genomic ◽  
The City

AbstractAnthropogenic environmental alterations such as urbanization can threaten native populations as well as create novel environments that allow human pests and pathogens to thrive. As the number and size of urban environments increase globally, it is more important than ever to understand the dispersal dynamics of hosts, vectors and pathogens of zoonotic disease systems. For example, a protozoan parasite and the causative agent of Chagas disease in humans, Trypanosoma cruzi, recently colonized and spread through the city of Arequipa, Peru. We used population genomic and phylogenomic tools to analyze whole genomes of 123 T. cruzi isolates collected throughout Arequipa to determine patterns of T. cruzi dispersal. The data show significant population genetic structure within city blocks-parasites in the same block tend to be very closely related - but no population structure among blocks within districts - parasites in neighboring blocks are no more closely related to one another than to parasites in distant districts. These data suggest that T. cruzi dispersal within a block occurs regularly and that occasional long-range dispersal events allow the establishment of new T. cruzi populations in distant blocks. Movement of domestic animals may be the primary mechanism of inter-block and inter-district T. cruzi dispersal.Author SummaryUrbanization creates environments that are ideal for some human pests and pathogens. As the number and size of urban environments increases globally, it is becoming vital to understand how human disease-causing pathogens, their vectors, and their non-human hosts disperse through urban landscapes. Here we study a population of Trypanosoma cruzi – the protozoan parasite and causative agent of Chagas disease in humans – that recently colonized the city of Arequipa, Peru. We use population genomic and phylogenomic tools to understand how this parasite population dispersed through the city to achieve its current distribution and abundance. We show that T. cruzi collected from the same city block tend to be very closely related, while those from neighboring blocks are often as distantly related as those from blocks in distant districts. The data suggest that vectors facilitate frequent within-block dispersal of the parasite, while domestic animal movement may facilitate the relatively infrequent inter-block and interdistrict dispersal.

scholarly journals Biotherapic of Trypanosoma cruzi 17d increases apoptosis in experimentally infected mice

2021 ◽  
Vol 10 (36) ◽  
pp. 119-124
Author(s):  
Patrícia Flora Sandri ◽  
Gislaine Janaina Sanchez Falkowski ◽  
Luzmarina Hernandes ◽  
Márcia Machado de Oliveira Dalálio ◽  
Denise Lessa Aleixo ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Controlled Trial ◽  
Basic Research ◽  
Treated Group ◽  
Oral Route ◽  
Control Group ◽  
Phagocytic Cells ◽  
Number Of Cells

Introduction: the mechanism of action of ultradiluted medicines has not yet been established[1,3]. Many basic research studies have focused on isopathic models using in vitro or in vivo designs [4,5]. Recent studies indicate that an ultradiluted (isopathic) antigen can transfer signals to the immune system and modulate its response when an organism is challenged against this same antigen [6]. Some studies on experimental infection of mice by T. cruzi identified apoptotic cells and showed that the increase of their number is associated with an increase also in the number of parasites in the blood of the infected animals, while blockage of apoptosis can be the target of therapeutic intervention [7,8]. Aim: to evaluate the development of apoptosis in mice treated with biotherapic of Trypanosoma cruzi in dilution 17d through in situ detection of fragmented DNA. Method: in a blind randomized controlled trial, 36 male Swiss mice age 4 or 8 weeks were distributed in groups control - treated with 7% hydroalcoholic solution(CI-4=9 animals or CI-8=9 animals); and treated with biotherapic 17d (BIOT-4=9 animals or BIOT-8=9 animals). Infection was performed with 1,400 trypomastigotes T. cruzi-strain Y via intraperitoneal. Biotherapic 17d was prepared through the addition of 0.9ml of concentrated T. cruzi (10E+7 trypomastigotes/ml) to 9.1 ml of distilled water. The following dilutions were prepared in 86% hydroalcoholic solution until dilution 16d. Dilution 17d was prepared with 7% hydroalcoholic solution. It was performed microbiological control and biological risk in vivo. Treatment: 0.2 ml in 3 consecutive days, oral route, from the moment infection was verified. Animals were sacrificed on the 3rd day of treatment in a chamber saturated with ether. The liver and spleen were removed and fixated in 4% paraformaldehyde for 24 hours and then included in paraffin. Apoptosis was evaluated through DNA fragmentation – TUNEL technique (TdT dUTP-biotin Nick End Labeling (ApopTag® Peroxidade-Chemicon). For statistical analysis software Statistica 8.0 was used. This study was approved by the Ethics Committee for Animal Experimentation of UEM. Results and Discussion: in the samples of liver of animals age 4 and 8 weeks either treated or not with biotherapic 17d it was found cells parasitized by amastigotes of T. cruzi with apoptotic bodies, or phagocytic cells with phagocytic vacuole with apoptotic marked material inside them. The number of cells in apoptosis in animals age 4 weeks was not significantly (p=0.03) larger in treated group BIOT-C4 than in control group CI-4 (Figure 1). In animals age 8 weeks, the number of cells in apoptosis was significantly (p

scholarly journals Identification of Inhibitors to Trypanosoma cruzi Sirtuins Based on Compounds Developed to Human Enzymes

2020 ◽  
Vol 21 (10) ◽  
pp. 3659
Author(s):  
Tanira Matutino Bastos ◽  
Milena Botelho Pereira Soares ◽  
Caio Haddad Franco ◽  
Laura Alcântara ◽  
Lorenzo Antonini ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Mammalian Cells ◽  
Drug Target ◽  
Drug Targets ◽  
Synergistic Effects ◽  
Protozoan Parasite ◽  
Disease Treatment ◽  
Specific Parasite ◽  
Specific Inhibitors

Chagas disease is an illness caused by the protozoan parasite Trypanosoma cruzi, affecting more than 7 million people in the world. Benznidazole and nifurtimox are the only drugs available for treatment and in addition to causing several side effects, are only satisfactory in the acute phase of the disease. Sirtuins are NAD+-dependent deacetylases involved in several biological processes, which have become drug target candidates in various disease settings. T. cruzi presents two sirtuins, one cytosolic (TcSir2rp1) and the latter mitochondrial (TcSir2rp3). Here, we characterized the effects of human sirtuin inhibitors against T. cruzi sirtuins as an initial approach to develop specific parasite inhibitors. We found that, of 33 compounds tested, two inhibited TcSir2rp1 (15 and 17), while other five inhibited TcSir2rp3 (8, 12, 13, 30, and 32), indicating that specific inhibitors can be devised for each one of the enzymes. Furthermore, all inhibiting compounds prevented parasite proliferation in cultured mammalian cells. When combining the most effective inhibitors with benznidazole at least two compounds, 17 and 32, demonstrated synergistic effects. Altogether, these results support the importance of exploring T. cruzi sirtuins as drug targets and provide key elements to develop specific inhibitors for these enzymes as potential targets for Chagas disease treatment.

scholarly journals Lipophilic Antifolate Trimetrexate Is a Potent Inhibitor of Trypanosoma cruzi: Prospect for Chemotherapy of Chagas' Disease

2005 ◽  
Vol 49 (8) ◽  
pp. 3234-3238 ◽  
Author(s):  
Olga Senkovich ◽  
Vandanajay Bhatia ◽  
Nisha Garg ◽  
Debasish Chattopadhyay
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Dihydrofolate Reductase ◽  
Drug Target ◽  
Potent Inhibitor ◽  
Pneumocystis Carinii ◽  
Lethal Dose ◽  
Public Health Problem ◽  
Protozoan Parasite ◽  
Track Record

ABSTRACT Trypanosoma cruzi, a protozoan parasite, is the causative agent for Chagas' disease, which poses serious public health problem in Latin America. The two drugs available for the treatment of this disease are effective only against recent infections and are toxic. Dihydrofolate reductase (DHFR) has a proven track record as a drug target. The lipophilic antifolate trimetrexate (TMQ), which is an FDA-approved drug for the treatment of Pneumocystis carinii infection in AIDS patients, is a potent inhibitor of T. cruzi DHFR activity, with an inhibitory constant of 6.6 nM. The compound is also highly effective in killing T. cruzi parasites. The 50 and 90% lethal dose values against the trypomastigote are 19 and 36 nM, and the corresponding values for the amastigote form are 26 and 72 nM, respectively. However, as TMQ is also a good inhibitor of human DHFR, further improvement of the selectivity of this drug would be preferable. Identification of a novel antifolate selective against T. cruzi would open up new therapeutic avenues for treatment of Chagas' disease.

scholarly journals Insecticidal efficacy of afoxolaner against bedbugs, Cimex lectularius, when administered orally to dogs

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 7 ◽  
Author(s):  
Frederic Beugnet ◽  
Carin Rautenbach ◽  
Luther van der Mescht ◽  
Wilfried Lebon ◽  
Nesrine Aouiche ◽  
...  
Keyword(s):  
Experimental Study ◽  
Treated Group ◽  
Cimex Lectularius ◽  
Control Group ◽  
Bed Bug ◽  
Time Points ◽  
Insecticidal Efficacy

The objective of this experimental study was to assess the insecticidal efficacy of afoxolaner (NexGard®) against bedbugs (Cimex lectularius) on dogs. For each challenge, 20 bedbugs were placed in two chambers positioned in contact to the dog’s skin for 15 min, after which live fed parasites were counted and incubated for survival evaluations. On Day 0, 7 dogs assigned to the treated group were administered afoxolaner orally at the registered dose. All 14 dogs were challenged on Days 1, 7, 14, 21 and 28, and the collected live fed C. lectularius incubated for 72 h (Day 1), and 72 h and 96 h (Days 7, 14, 21 and 28) for survival evaluation. The percent feeding in the control group ranged from 95% to 98.6% and the percent of live fed bedbugs at 96 h ranged from 99.3% to 100% in the control group, demonstrating the viability of the strain and their capacity to feed on dogs. Significantly fewer live fed bedbugs were counted in the treated group, compared to the control group, at all time-points. The reduction of live fed C. lectularius in the afoxolaner group was 41.4% at 72 h after the Day 1 challenge, and 77.2%, 82.7%, 85.0% and 63.5% at 96 h after the Days 7, 14, 21 and 28 challenges, respectively. It is hypothesized that monthly treatment of dogs with afoxolaner could help in preventing a bed bug population from installing in a household if bedbugs bite dogs in the presence of humans.

scholarly journals LEVANTAMENTO DA OCORRÊNCIA DE TRIATOMÍNEOS EM ÁREA PERIURBANA NA CIDADE DE PORTO VELHO – RO

2016 ◽  
Vol 5 (2) ◽  
pp. 9
Author(s):  
Paulo de Tarso Nunes Silva da Costa Júnior ◽  
Alda E. F. Lobato da Cunha
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Insect Vector ◽  
Control Center ◽  
Medical Entomology ◽  
Molecular Tests ◽  
Two Stages ◽  
The City ◽  
Rhodnius Robustus ◽  
Porto Velho

Os triatomíneos, popularmente conhecido como barbeiro, sendo tal o agente transmissor da doença de Chagas no Brasil e nas Américas. Em Porto Velho, município de Rondônia, ainda não se tem estudos de notificações que venha divulgar números de casos da doença de Chagas notificado. O objetivo do estudo foi realizar um levantamento da ocorrência do vetor da doença de Chagas em uma área periurbana da cidade Porto Velho, no bairro Ronaldo Aragão, na linha Progresso. Esta localidade foi selecionada por constante ocorrência do inseto vetor, os quais após coletados por moradores do domicilio foram enviados ao laboratório de entomologia do Centro de Controle de Zoonoses e posteriormente ao LACEN-RO. As coletas entomológicas tiveram duas etapas, em campo e em laboratório, a análise do material coletado foi no laboratório de entomologia médica no LACEN-RO. Os resultados obtidos das 16 coletas, através de busca ativa, com nenhum registro do vetor da Chagas. Mas das buscas passivas, obteve-se um total de 14 exemplares de triatomíneos, das quais houve prevalência da espécie Rhodnius robustus e apenas 01 exemplar de Rhodnius pictipes, e dentre estes, um triatomíneo estava positivo com Trypanosoma cruzi. Sugerimos novas coletas entomológicas, objetivando um maior numero de exemplares de triatomíneos, tanto na área deste estudo, como em outras localidades neste município e outros ecótopos, e ainda realizar o isolamento das amostras de Trypanosoma cruzi para fins da possibilidade da realização de testes moleculares.ABSTRAT The triatomíneos, popularly are known as barber, being such the transmitter agent of the Chagas disease in Brazil and in the Americas. In Porto Velho, city of Rondonia, there are not studies of notifications that come to divulge numbers of cases of chagas notified. The objective of the study was to do a survey of the occurrence for Chagas’ disease vector in the suburbs of the city of Porto Velho, in the Ronaldo Aragao, neighborhood ,in the line Progress. This locality was selected by constant occurrence of the insect vector, which after collected for inhabitants of the home are sent to the laboratory of entomology of the Control Center of Zoonoses and later to the LACEN-RO. The entomologicals collections had two stages, in field and in laboratory, the analysis of the collected material was in the laboratory of medical entomology in the LACEN-RO. The obtained results of the 16 collections, through passive searches, it was obtained a total of 14 types of of triatomíneos , of which had prevalence of the Rhodnius robustus species and only 01 type of Rhodnius pictipes, and among these, a triatomíneo was positive with Trypanosoma cruzi. We suggested new entomologicals collections, objectifying a larger number of triatomíneos types, so much in the area of this study, as in other localities in this city and other environments, and still to do through the isolation of the samples of Trypanosoma cruzi for ends of the possibility of accomplishment of molecular tests.

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