Paleoparasitology of Chagas disease: a review

Wildlife parasitology: sample collection and processing, diagnostic constraints, and methodological challenges in terrestrial carnivores

Wild terrestrial carnivores play a crucial role as reservoir, maintenance, and spillover hosts for a wide parasite variety. They may harbor, shed, and transmit zoonotic parasites and parasites of veterinary importance for domestic hosts. Although wild carnivores are globally distributed and comprise many different species, some living in close proximity to human settlements, only a few studies have investigated parasites of wild terrestrial carnivores using non-specific techniques. Access to samples of wild carnivores may be challenging as some species are protected, and others are secretive, possibly explaining the data paucity. Considering the importance of wild carnivores' health and ecological role, combined with the lack of specific diagnostic methodologies, this review aims to offer an overview of the diagnostic methods for parasite investigation in wild terrestrial carnivores, providing the precise techniques for collection and analysis of fecal, blood, and tissue samples, the environmental impact on said samples, and the limitations researchers currently face in analyzing samples of wild terrestrial carnivores. In addition, this paper offers some crucial information on how different environmental factors affect parasite detection postmortem and how insects can be used to estimate the time of death with a specific highlight on insect larvae. The paper contains a literature review of available procedures and emphasizes the need for diagnostic method standardization in wild terrestrial carnivores.

Vector species richness predicts local mortality rates from Chagas disease

Vector species richness may drive the prevalence of vector-borne diseases by influencing pathogen transmission rates. The dilution effect hypothesis predicts that higher biodiversity reduces disease prevalence, but with inconclusive evidence. In contrast, the amplification effect hypothesis suggests that higher vector diversity may result in greater disease transmission by increasing and diversifying the transmission pathways. The relationship between vector diversity and pathogen transmission remains unclear and requires further study. Chagas disease is a vector-borne disease most prevalent in Brazil and transmitted by multiple species of insect vectors of the subfamily Triatominae, yet the drivers of spatial variation in its impact on human populations remain unresolved. We tested whether triatomine species richness, latitude, bioclimatic variables, human host population density, and socioeconomic variables predict Chagas disease mortality rates across over 5000 spatial grid cells covering all of Brazil. Results show that species richness of triatomine vectors is a good predictor of mortality rates caused by Chagas disease, which supports the amplification effect hypothesis. Vector richness and the impact of Chagas disease may also be driven by latitudinal components of climate and human socioeconomic factors. We provide evidence that vector diversity is a strong predictor of disease prevalence and give support to the amplification effect hypothesis.

Antiparasitic Activity of Plumbago auriculata Extracts and Its Naphthoquinone Plumbagin against Trypanosoma cruzi

Chagas disease (CD) caused by the protozoan Trypanosoma cruzi affects more than six million people worldwide. Treatment is restricted to benznidazole (Bz) and nifurtimox (Nf) that display low activity in the later chronic stage besides triggering toxic events that result in treatment abandonment. Therefore, new therapeutic options are necessary. In this scenario, natural products emerge as promising alternatives to treat CD. In the family Plumbaginaceae, Plumbago sp. exhibits a broad spectrum of biological and pharmacological activities. Thus, our main objective was to evaluate, in vitro and in silico, the biological effect of crude extracts of root and of aerial parts of P. auriculata, as well as its naphthoquinone Plumbagin (Pb) against T. cruzi. The phenotypic assays revealed potent activity of the root extract against different forms (trypomastigote and intracellular forms) and strains (Y and Tulahuen), with a compound concentration that reduced 50% of the number of the parasite (EC₅₀) values ranging from 1.9 to 3.9 µg/mL. In silico analysis showed that Pb is predicted to have good oral absorption and permeability in Caco2 cells, besides excellent probability of absorption by human intestinal cells, without toxic or mutagenic potential effects, not being predicted as a substrate or inhibitor of P-glycoprotein. Pb was as potent as Bz against intracellular forms and displayed a superior trypanosomicidal effect (about 10-fold) in bloodstream forms (EC₅₀ = 0.8 µM) as compared to the reference drug (8.5 µM). The cellular targets of Pb on T. cruzi were evaluated using electron microscopy assays and the findings on bloodstream trypomastigotes showed several cellular insults related to the autophagic process. Regarding toxicity in mammalian cells, the root extracts and the naphthoquinone present a moderate toxic profile on fibroblasts and cardiac cell lines. Then, aiming to reduce host toxicity, the root extract and Pb were tested in combination with Bz, and the data showed additive profiles with the sum of the fractional inhibitory concentration indexes (ΣFICIs) being 1.45 and 0.87, respectively. Thus, our work reveals the promising antiparasitic activity of Plumbago auriculata crude extracts and its purified naphthoquinone Plumbagin against different forms and strains of Trypanosoma cruzi in vitro.

Aktuelle Handlungsempfehlungen für die amerikanische Trypanosomiasis oder Chagas-Krankheit

Die amerikanische Trypanosomiasis oder auch Chagas-Krankheit wird durch das Protozoon Trypanosoma cruzi verursacht. Vor allem unerkannt und unbehandelt kann sie zu schwerwiegenden Organschäden bis hin zum Tod führen. Weltweit geht man aktuell von 6–7 Mio. Infizierten aus. Initial eher auf ländliche Gebiete in Lateinamerika beschränkt, breitete sich die Infektion durch Populationsbewegungen und nichtvektorielle Übertragungswege auf große Städte sowie in nichtendemische Regionen weltweit aus. Die WHO zählt die Chagas-Krankheit zu den sog. vernachlässigten Tropenerkrankungen und nur ein kleiner Bruchteil der Betroffenen erhält eine adäquate Versorgung. Im Herbst 2022 wurden erstmals Handlungsempfehlungen für Deutschland veröffentlicht. Sie sollen der Vernachlässigung entgegenwirken, nichtvektorielle Übertragungswege unterbinden und durch adäquates Management die assoziierte sozio-ökonomische Belastung, Morbidität und Mortalität verringern.

Genomic palaeoparasitology traced the occurrence of Taenia asiatica in ancient Iran (Sassanid Empire, 2th cent. CE-6th cent. CE)

Palaeoparasitology investigates parasitological infections in animals and humans of past distance by examining biological remains. Palaeofaeces (or coprolites) are biological remains that provide valuable information on the disease, diet, and population movements in ancient times. Today, advances in detecting ancient DNA have cast light on dark corners that microscopy could never reach. The archaeological site of the Chehrabad salt mine of Achaemenid (550–330 BC) and Sassanid (third–seventh century AD) provides remains of various biotic and abiotic samples, including animal coprolites, for multidisciplinary studies. In the present work, we investigated coprolites for helminth eggs and larvae by microscopy and traced their biological agents’ DNA by Next Generation Sequencing. Our results revealed various helminths, including Taenia asiatica, the species introduced in the 1990s. Implementing advanced modern molecular techniques like NGS gives a paramount view of pathogenic agents in space and time.

Socioecological vulnerability and the risk of zoonotic disease emergence in Brazil

In developing countries, outbreaks of zoonotic diseases (ZDs) result from intertwined ecological, socioeconomic, and demographic processes that shape conditions for (i) increased contact between vulnerable human population and wildlife in areas undergoing environmental degradation and (ii) the rapid geographic spread of infections across socially vulnerable regions. In Brazil, recent increases in environmental and social vulnerabilities, amplified by economic and political crises, are potential triggers for outbreaks. We discuss Brazilian features that favor outbreaks and show a novel quantitative method for zoonotic risk assessment. Using data on nine ZDs from 2001 to 2019, we found that the most significant causal variables were vegetation cover and city remoteness. Furthermore, 8 of 27 states presented low-level risk of ZD outbreaks. Given the ZD-bushmeat connection, we identified central hunted mammals that should be surveilled to prevent spillover events. The current challenge is to coordinate intersectoral collaboration for effective One Health management in megadiverse countries with high social vulnerability and growing environmental degradation like Brazil.

Thiosemicarbazone derivatives: Evaluation as cruzipain inhibitors and molecular modeling study of complexes with cruzain

The development of cruzipain inhibitors represents one of the most attractive challenges in the search for drugs for the treatment of Chagas disease. A recombinant form of this enzyme, cruzain, has been crystallized with numerous inhibitors, excluding thiosemicarbazones. These compounds have been established as potent inhibitors of cruzain, although there is very little data in the literature of thiosemicarbazones tested on cruzipain. In this work, we present the results of the evaluation of eleven thiosemicarbazones on cruzipain, isolated from T. cruzi epimastigotes, six of them previously evaluated on cruzain. For these latter, we studied through computational methods, the mode of interaction with the active site of cruzain and the contribution of geometric parameters to the possible mechanism of action involved in the observed inhibition. Finally, from some geometric parameters analyzed on modeled TSC-cruzain complexes, a semi-quantitative relationship was established that could explain the inhibitory activity of thiosemicarbazones on cruzipain, the enzyme actually present in the parasite.

The Politics of (Non)endemicity: Chagas Disease in the United States

Chagas disease (CD) is a vector-borne parasitic disease endemic to Latin America. The US has established populations of vectors, parasites, and animal hosts, but because of the low frequency of locally acquired human infections CD is not classified as endemic there. I present a narrative review of the literature of autochthonous cases of CD in the US and analyze it with a co-productionist framework focused on material politics. I underscore the need for an ethnographic approach to the category of endemicity as not only an issue of knowledge and evidence but also as a practiced condition infused with power.

Utility of a Fluid Library with Samples of Humans, Reservoirs and Vectors Collected in Filter Paper, for Retrospective Diagnosis of American Trypanosomiasis in Endemic Areas of Venezuela

INTRODUCTION

We define a fluid library as a library of samples of different biological fluids (from humans, animals or vectors) collected and properly stored on filter paper, which allows retrospective studies, especially of diagnosis or detection of infectious agents in these samples, using different techniques. The objective of this work was the retrospective diagnosis of American trypanosomiasis by PCR in a Venezuelan endemic area using a fluid library.

METHODS

A fluid library with samples that had been collected on filter paper, 5 years ago, was used for the detection of Trypanosoma cruzi DNA. 165 blood samples of humans, 30 samples of 25 animals (Didelphis marsupialis, Canis familiaris, Equus asinus and Felis catus) and 8 samples of vectors from endemic areas of Anzoátegui state, were analysed by PCR.

RESULTS

The results revealed that 16.4% of the humans samples were positive, 11.1% of those detected positive were children younger than 10 years old, and 26.72% young people aged 11-20 years, suggesting that T. cruzi infection has been active for the past two decades. 56% of the animal samples showed amplification; Didelphis marsupialis 66%, Canis familiaris 54.5%, Equus asinus 50%, and Felis catus 33.3%. On the other hand, positivity (50%) was detected in the studied vectors, of which the 3 most important species in Venezuela (Rhodnius prolixus, Triatoma maculata and Panstrongylus geniculatus) were involved.

CONCLUSIONS

The PCR using a fluid library allowed the detection of T. cruzi DNA in old samples from the three host of the epidemiological chain, suggesting that retrospective diagnosis can be made through this strategy and demonstrate that there has been active transmission, which helps to clarify the epidemiological situation in areas where there are no previous reports.

Chagas bugs and trypanosoma cruzi: Puppets and puppeteer?

A widely accepted idea in parasite-host relationships is that the former manipulates the latter so that it increases its own success. In the case of complex life cycles, this means that the parasite is able to manipulate the first host which allows its transmission to the second host. In this paper, I formalize the idea that this may be the case for the Trypanosoma cruzi parasite and its vectors, bugs of the subfamily Triatominae. I discuss the sources of existing evidence and propose some types of manipulation. This manipulation could also occur in the second host, that is, a vertebrate. Here, I emphasize humans and domesticated animals. I also discuss how global change and insecticide resistance may drive the arms race between both, triatomines and T. cruzi, and host manipulation.

The current drug discovery landscape for trypanosomiasis and leishmaniasis: Challenges and strategies to identify drug targets

Human trypanosomiasis and leishmaniasis are vector-borne neglected tropical diseases caused by infection with the protozoan parasites Trypanosoma spp. and Leishmania spp., respectively. Once restricted to endemic areas, these diseases are now distributed worldwide due to human migration, climate change, and anthropogenic disturbance, causing significant health and economic burden globally. The current chemotherapy used to treat these diseases has limited efficacy, and drug resistance is spreading. Hence, new drugs are urgently needed. Phenotypic compound screenings have prevailed as the leading method to discover new drug candidates against these diseases. However, the publication of the complete genome sequences of multiple strains, advances in the application of CRISPR/Cas9 technology, and in vivo bioluminescence-based imaging have set the stage for advancing target-based drug discovery. This review analyses the limitations of the narrow pool of available drugs presently used for treating these diseases. It describes the current drug-based clinical trials highlighting the most promising leads. Furthermore, the review presents a focused discussion on the most important biological and pharmacological challenges that target-based drug discovery programs must overcome to advance drug candidates. Finally, it examines the advantages and limitations of modern research tools designed to identify and validate essential genes as drug targets, including genomic editing applications and in vivo imaging.

Noninvasive Biological Samples to Detect and Diagnose Infections due to Trypanosomatidae Parasites: A Systematic Review and Meta-Analysis

Unicellular eukaryotes of the Trypanosomatidae family include human and animal pathogens that belong to the Trypanosoma and Leishmania genera. Diagnosis of the diseases they cause requires the sampling of body fluids (e.g., blood, lymph, peritoneal fluid, cerebrospinal fluid) or organ biopsies (e.g., bone marrow, spleen), which are mostly obtained through invasive methods. Body fluids or appendages can be alternatives to these invasive biopsies but appropriateness remains poorly studied. To further address this question, we perform a systematic review on clues evidencing the presence of parasites, genetic material, antibodies, and antigens in body secretions, appendages, or the organs or proximal tissues that produce these materials. Paper selection was based on searches in PubMed, Web of Science, WorldWideScience, SciELO, Embase, and Google. The information of each selected article (n = 333) was classified into different sections and data were extracted from 77 papers. The presence of Trypanosomatidae parasites has been tracked in most of organs or proximal tissues that produce body secretions or appendages, in naturally or experimentally infected hosts. The meta-analysis highlights the paucity of studies on human African trypanosomiasis and an absence on animal trypanosomiasis. Among the collected data high heterogeneity in terms of the I2 statistic (100%) is recorded. A high positivity is recorded for antibody and genetic material detection in urine of patients and dogs suffering leishmaniasis, and of antigens for leishmaniasis and Chagas disease. Data on conjunctival swabs can be analyzed with molecular methods solely for dogs suffering canine visceral leishmaniasis. Saliva and hair/bristles showed a pretty good positivity that support their potential to be used for leishmaniasis diagnosis. In conclusion, our study pinpoints significant gaps that need to be filled in order to properly address the interest of body secretion and hair or bristles for the diagnosis of infections caused by Leishmania and by other Trypanosomatidae parasites.

Trypanosoma cruzi transmission dynamics in a synanthropic and domesticated host community

Trypanosoma cruzi is the causative agent of Chagas disease, a Neglected Tropical Disease affecting 8 million people in the Americas. Triatomine hematophagous vectors feed on a high diversity of vertebrate species that can be reservoirs or dead-end hosts, such as avian species refractory to T. cruzi. To understand its transmission dynamics in synanthropic and domesticated species living within villages is essential to quantify disease risk and assess the potential of zooprophylaxis. We developed a SI model of T. cruzi transmission in a multi-host community where vector reproduction and parasite transmission depend on a triatomine blood-feeding rate accounting for vector host preferences and interference while feeding. The model was parameterized to describe T. cruzi transmission in villages of the Yucatan peninsula, Mexico, using the information about Triatoma dimidiata vectors and host populations accumulated over the past 15 years. Extensive analyses of the model showed that dogs are key reservoirs and contributors to human infection, as compared to synanthropic rodents and cats, while chickens or other domesticated avian hosts dilute T. cruzi transmission despite increasing vector abundance. In this context, reducing the number of dogs or increasing avian hosts abundance decreases incidence in humans by up to 56% and 39%, respectively, while combining such changes reduces incidence by 71%. Although such effects are only reached over >10-years periods, they represent important considerations to be included in the design of cost-effective Integrated Vector Management. The concomitant reduction in T. cruzi vector prevalence estimated by simulating these zooprophylactic interventions could indeed complement the removal of colonies from the peridomiciles or the use of insect screens that lower vector indoor abundance by ~60% and ~80%. These new findings reinforce the idea that education and community empowerment to reduce basic risk factors is a cornerstone to reach and sustain the key objective of interrupting Chagas disease intra-domiciliary transmission.

Chagas Disease: From Discovery to a Worldwide Health Problem

Carlos Chagas discovered American trypanosomiasis, also named Chagas disease (CD) in his honor, just over a century ago. He described the clinical aspects of the disease, characterized by its etiological agent (Trypanosoma cruzi) and identified its insect vector. Initially, CD occurred only in Latin America and was considered a silent and poorly visible disease. More recently, CD became a neglected worldwide disease with a high morbimortality rate and substantial social impact, emerging as a significant public health threat. In this context, it is crucial to better understand better the epidemiological scenarios of CD and its transmission dynamics, involving people infected and at risk of infection, diversity of the parasite, vector species, and T. cruzi reservoirs. Although efforts have been made by endemic and non-endemic countries to control, treat, and interrupt disease transmission, the cure or complete eradication of CD are still topics of great concern and require global attention. Considering the current scenario of CD, also affecting non-endemic places such as Canada, USA, Europe, Australia, and Japan, in this review we aim to describe the spread of CD cases worldwide since its discovery until it has become a global public health concern.

Mummy studies and the bioarchaeology of care

The bioarchaeology of care is a framework through which researchers can begin to infer the level of care an individual may have required based on the presence of paleopathological evidence. To date, all of the research that has employed the framework has been based on evidence derived from skeletal material. This special issue was organized in order to highlight how the analysis of mummified soft tissue, as well as other sources of data commonly associated with mummified remains, such as coprolites and intestinal contents, has the potential to provide valuable insight into the reconstruction of care in the past.

Parasitic interactions among Trypanosoma cruzi, triatomine vectors, domestic animals, and wildlife in Big Bend National Park along the Texas-Mexico border

National parks attract millions of visitors each year. Park visitors, employees, and pets are at risk of infection with various zoonotic pathogens, including Trypanosoma cruzi, causative agent of Chagas disease. Big Bend National Park is located along the Texas-Mexico border in a region with endemic triatomine insects- vectors of T. cruzi- yet the degree to which the parasite is transmitted in this region is unknown. We collected triatomines for T. cruzi detection and discrete typing unit (DTU) determination, and conducted blood meal analyses to determine recent hosts. As an index of domestic/peridomestic transmission, we tested residential dogs in the Park for exposure to T. cruzi. From 2015 to 2017, 461 triatomines of three species-Triatoma rubida, Triatoma gerstaeckeri, and Triatoma protracta-were collected in and around the Park. Adult triatomine encounters peaked in June of each year (52.8% of collections). We detected an overall infection prevalence of 23.1% in adult triatomines (n = 320) and 4.2% in nymph triatomines (n = 24). DTU TcI was the only T. cruzi strain detected. Of 89 triatomines subjected to blood meal analyses, vertebrate host DNA was successfully amplified from 42 (47.2%); blood meal sources included humans, domestic animals, and avian and mammalian wildlife species. Tested dogs were considered positive if reactive on at least two independent serologic assays; we found 28.6% seroprevalence in 14 dogs. These findings reveal interactions between infected triatomines, humans, dogs, and wildlife in and around Big Bend National Park, with potential risk of human disease.

Trypanosoma cruzi infection in naturally infected dogs from an endemic region of Cundinamarca, Colombia

The seropositivity and risk factors for Trypanosoma cruzi infection in dogs from a municipality of Cundinamarca, a central state of Colombia were studied. A total of 356 client-owned dogs from urban, peri-urban and rural areas of La Mesa municipality, (Cundinamarca, Colombia) were randomly selected. Blood samples were collected by venipuncture. Anti-T. cruzi antibodies were determined using the enzyme-linked immunosorbent assay (ELISA) method. Reactive ELISA sera were processed by indirect immunofluorescence to confirm the presence of anti-T. cruzi antibodies. Chi-square tests were conducted for statistical analysis. Serologic tests for T. cruzi infection showed a prevalence of 29.49% (105/356), the rural area show a highest T. cruzi infection pattern in comparison with the other zone locations. Two triatomine species were found through the study: Panstrongylus geniculatus (53.4%) and Rhodnius colombiensis (46.6%). The prevalence of positive vectors for parasite was of 52.1% (38/73). Additionally, a very close relation between triatomine bugs and dogs in the rural zone (1:3.1) was observed. These results are the first report of natural infection by T. cruzi in domestic dogs in La Mesa municipality. In conclusion, the presence of anti-T. cruzi antibodies in dogs in this area suggest vector transmission. There is a need for active surveillance programs throughout the La Mesa municipality and vector control strategies should also be implemented.

Chagas Cardiomyopathy: An Update of Current Clinical Knowledge and Management: A Scientific Statement From the American Heart Association

Background:

Chagas disease, resulting from the protozoan Trypanosoma cruzi , is an important cause of heart failure, stroke, arrhythmia, and sudden death. Traditionally regarded as a tropical disease found only in Central America and South America, Chagas disease now affects at least 300 000 residents of the United States and is growing in prevalence in other traditionally nonendemic areas. Healthcare providers and health systems outside of Latin America need to be equipped to recognize, diagnose, and treat Chagas disease and to prevent further disease transmission.

Methods and Results:

The American Heart Association and the Inter-American Society of Cardiology commissioned this statement to increase global awareness among providers who may encounter patients with Chagas disease outside of traditionally endemic environments. In this document, we summarize the most updated information on diagnosis, screening, and treatment of T cruzi infection, focusing primarily on its cardiovascular aspects. This document also provides quick reference tables, highlighting salient considerations for a patient with suspected or confirmed Chagas disease.

Conclusions:

This statement provides a broad summary of current knowledge and practice in the diagnosis and management of Chagas cardiomyopathy. It is our intent that this document will serve to increase the recognition of Chagas cardiomyopathy in low-prevalence areas and to improve care for patients with Chagas heart disease around the world.

Reestablishing rigor in archaeological parasitology

Archaeological parasitology originated in the mid-twentieth century with interdisciplinary teams of specialists directed by archaeologists. The goals of such studies were detailed analyses of dietary, medicinal, and environmental factors that shaped the patterns of infection. By the 1970s, a cadre of unique coprolite analysts was trained to analyze macroscopic and microscopic remains for integrated reconstructions of the cultural determinants of parasitism. During these first phases of research, diagnostic rigor was maintained by direct training of specialists in parasitology and archaeology sub-disciplines including archaeobotany and archaeopalynology. Near the end of the twentieth century, however, "paleoparasitology" was defined as a separate field focusing on defining parasite distribution through time and space. Ironically, this focus resulted in an increase in misdiagnosis, especially prominent after 2000. Paleoparasitology does not explicitly include other specialized studies in it research design. Thus, dietary, environmental and medicinal inferences have been neglected or lost as samples were destroyed solely for the purpose of parasitological analysis. Without ancillary archaeological studies, paleoparasitology runs the risk of separation from archaeological context, thereby reducing its value to the archaeologists who recover samples for analysis.

Drug repurposing strategy against Trypanosoma cruzi infection: In vitro and in vivo assessment of the activity of metronidazole in mono- and combined therapy

Metronidazole (Mtz) is a commercial broad-spectrum nitroimidazolic derivative with relevant antimicrobial activity and relative safety profile. Therefore, it is fair to consider Mtz a candidate for drug repurposing for other neglected conditions such as Chagas disease (CD), a parasitic pathology caused by Trypanosoma cruzi. CD is treated only with benznidazole (Bz) and nifurtimox, both introduced in clinics decades ago despite important limitations, including low efficacy on the later disease stage (chronic form) and severe side effects. New cheap and fast alternative treatments for CD are needed, thus the repurposing of Mtz was assessed in vitro and in vivo in mono- and combined therapy. In vitro assays demonstrated EC₅₀>200µM for Mtz, while for Bz the values ranged from 2.51µM (intracellular forms) to 11.5µM (bloodstream trypomastigotes). When both drugs were combined in fixed-ratio proportions, Mtz promoted Bz potency (lower EC₅₀ values). In vivo toxicity assays for Mtz in mice showed no adverse effects neither histopathological alterations up to 2000mg/kg. Regarding experimental T. cruzi infection, Bz 100mg/kg suppressed parasitemia while Mtz (up to 1000mg/kg) in monotherapy did not, but prolonged animal survival at 250 and 500 regimen doses. The combination of both drugs (Bz 10+Mtz 250) prevented mortality (70%) besides protected against electric cardiac alterations triggered by the parasite infection. Although not able to reduce parasite load, the combination therapy prevented animal mortality; this was possibly due to a protection of the electric cardiac physiology that is normally altered in experimental infection of T. cruzi. It also suggested that the interaction with Mtz could have improved the pharmacokinetics of Bz. Our study emphasizes the importance of drug repurposing and combined therapy for CD to contribute to alternative therapies for this neglected and silent pathology.

Transmissão da doença de Chagas por consumo de carne de caça: revisão sistemática

RESUMO: Objetivo: Avaliar a influência do consumo de carne de caça na transmissão da doença de Chagas (DC), assim como as condições em que ela ocorre e a frequência de relatos na literatura. Métodos: Mediante revisão sistemática, foram consultadas as bases PubMed, LILACS, MEDLINE e SciELO, sendo incluídos artigos escritos em português, inglês e espanhol, sem limitação do ano de publicação. Os descritores utilizados foram: oral, transmission, meat, wild animals, hunt, carnivory e Chagas disease, sendo inseridos na análise os artigos que mencionavam o consumo de carne de animais como forma de transmissão humana da DC. Foram utilizados critérios de evidência epidemiológico, clínico e laboratorial. Resultados: Entre os 298 artigos identificados, apenas seis preencheram os critérios de elegibilidade. Foram identificados somente cinco episódios de transmissão oral por consumo de carne ou sangue de animais silvestres, porém em dois deles não foi possível afastar a possibilidade de transmissão vetorial. A maior parte dos relatos preencheu os critérios de evidência epidemiológico, clínico e laboratorial, estabelecidos para sustentar a transmissão. Conclusão: Apesar da transmissão de DC ser incomum, a caça e o consumo de mamíferos silvestres reservatórios devem ser desestimulados nos países endêmicos em função dos riscos inerentes a essas práticas.

Assessing the Archaeoparasitological Potential of Quids As a Source Material for Immunodiagnostic Analyses

In the present study, quids from La Cueva de los Muertos Chiquitos (CMC) were subjected to ELISA tests for 2 protozoan parasites, Toxoplasma gondii (n=45) and Trypanosoma cruzi (n=43). The people who occupied CMC, the Loma San Gabriel, lived throughout much of present-day Durango and Zacatecas in Mexico. The known pathoecology of these people puts them into at-risk categories for the transmission of T. gondii and T. cruzi. Human antibodies created in response to these 2 parasites can be detected in modern saliva using ELISA kits intended for use with human serum. For these reasons, quids were reconstituted and subjected to ELISA testing. All test wells yielded negative results. These results could be a factor of improper methods because there is no precedence for this work in the existing literature. The results could equally be a simple matter of parasite absence among those people who occupied CMC. A final consideration is the taphonomy of human antibodies and whether or not ELISA is a sufficient method for recovering antibodies from archaeological contexts. An additional ELISA test targeting secretory IgA (sIgA) was conducted to further examine the failure to detect parasite-induced antibodies from quids. Herein, the methods used for quid preparation and ELISA procedures are described so that they can be further developed by future researchers. The results are discussed in light of the potential future of quid analysis.

Complexity and multi-factoriality of Trypanosoma cruzi sylvatic cycle in coatis, Nasua nasua (Procyonidae), and triatomine bugs in the Brazilian Pantanal

Background

Trypanosoma cruzi is dispersed in nature through many transmission mechanisms among a high diversity of vectors and mammalian species, representing particular behaviors and habitats. Thus, each locality has a unique set of conditions underlying the maintenance of this parasite in the wild. The aim of the present study was to evaluate the life-cycle of T. cruzi in free-ranging coatis from the central region of the Brazilian Pantanal using a multi-factorial approach.

Methods

Three methodological blocks were used in the present study: (i) We evaluated T. cruzi infection using serological (ELISA) and parasitological (hemoculture) tests in free-ranging coatis captured from October 2010 to March 2012. In addition, we characterized T. cruzi isolates as DTUs (Discrete Typing Units); (ii) We evaluated Trypanosoma infection in species of Triatoma and Rhodnius inhabiting coati arboreal nests from May to September 2012 using parasitological and molecular assays; and (iii) We analyzed a set of longitudinal data (from 2005 to 2012) concerning the effects of T. cruzi infection on this coati population. Herein, we investigated whether seasonality, host sex, and host age influence T. cruzi prevalence and patterns of infection.

Results

The 2010–2012 period presented high seroprevalence on coatis (72.0 % ELISA) and a high percentage of individuals with infectivity competence (20.5 % positive hemoculture). All isolates presented TcI band patterns, occurring in single (n = 3) and mixed infections (1 TcI/T. rangeli; 4 with undefined characterization). Both male and female individuals presented the same transmission potential, expressed as positive hemoculture, which was only detected in the summer. However, overall, the data (2005–2012) highlighted the importance of females for T. cruzi maintenance in the winter. Moreover, twenty-three (67.6 %) bugs from five coati nests (71.4 %) were infected with flagellated forms. Seventeen samples were characterized as T. cruzi (TcI and TcIII genotypes).

Conclusion

In the Pantanal region, T. cruzi is transmitted in a complex, multifactorial, dynamic and non-linear transmission web. The coati nests might be inserted in this web, acting as important transmission foci at the arboreal stratum to different mammal species with arboreal or scansorial behavior.

Insights from paleomicrobiology into the indigenous peoples of pre-colonial America - a review

This review investigates ancient infectious diseases in the Americas dated to the pre-colonial period and considers what these findings can tell us about the history of the indigenous peoples of the Americas. It gives an overview, but focuses on four microbial pathogens from this period: Helicobacter pylori, Mycobacterium tuberculosis, Trypanosoma cruzi and Coccidioides immitis, which cause stomach ulceration and gastric cancer, tuberculosis, Chagas disease and valley fever, respectively. These pathogens were selected as H. pylori can give insight into ancient human migrations into the Americas, M. tuberculosis is associated with population density and urban development, T. cruzi can elucidate human living conditions and C. immitis can indicate agricultural development. A range of methods are used to diagnose infectious disease in ancient human remains, with DNA analysis by polymerase chain reaction one of the most reliable, provided strict precautions are taken against cross contamination. The review concludes with a brief summary of the changes that took place after European exploration and colonisation.

Arthropods of the great indoors: characterizing diversity inside urban and suburban homes

Although humans and arthropods have been living and evolving together for all of our history, we know very little about the arthropods we share our homes with apart from major pest groups. Here we surveyed, for the first time, the complete arthropod fauna of the indoor biome in 50 houses (located in and around Raleigh, North Carolina, USA). We discovered high diversity, with a conservative estimate range of 32-211 morphospecies, and 24-128 distinct arthropod families per house. The majority of this indoor diversity (73%) was made up of true flies (Diptera), spiders (Araneae), beetles (Coleoptera), and wasps and kin (Hymenoptera, especially ants: Formicidae). Much of the arthropod diversity within houses did not consist of synanthropic species, but instead included arthropods that were filtered from the surrounding landscape. As such, common pest species were found less frequently than benign species. Some of the most frequently found arthropods in houses, such as gall midges (Cecidomyiidae) and book lice (Liposcelididae), are unfamiliar to the general public despite their ubiquity. These findings present a new understanding of the diversity, prevalence, and distribution of the arthropods in our daily lives. Considering their impact as household pests, disease vectors, generators of allergens, and facilitators of the indoor microbiome, advancing our knowledge of the ecology and evolution of arthropods in homes has major economic and human health implications.

[Frontier, sugarcane and trafficking: slavery, disease and death in Capivari, São Paulo, 1821-1869]

The deaths and diseases of slaves in the São Paulo State sugarcane municipality of Capivari are addressed, associating the causes attributed to these deaths to the social and economic context and characteristics of the local slave communities. The impact of malaria, relating it to the age brackets, the environment created by work on the sugarcane plantations and the evolution of the occupation of the area, initially by expanding frontiers, is emphasized. The relationship between illness and work processes, as well as the post-disembarkation mortality of Africans and the possibility of mortality crises among the sugarcane captives is explored. The results lead to a discussion of the impact of habitat and Atlantic displacement and the difficulty in acclimatizing.

Palaeoparasitology - Human Parasites in Ancient Material

Parasite finds in ancient material launched a new field of science: palaeoparasitology. Ever since the pioneering studies, parasites were identified in archaeological and palaeontological remains, some preserved for millions of years by fossilization. However, the palaeoparasitological record consists mainly of parasites found specifically in human archaeological material, preserved in ancient occupation sites, from prehistory until closer to 2015. The results include some helminth intestinal parasites still commonly found in 2015, such as Ascaris lumbricoides, Trichuris trichiura and hookworms, besides others such as Amoebidae and Giardia intestinalis, as well as viruses, bacteria, fungi and arthropods. These parasites as a whole provide important data on health, diet, climate and living conditions among ancient populations. This chapter describes the principal findings and their importance for knowledge on the origin and dispersal of infectious diseases.

Domestic, peridomestic and wild hosts in the transmission of Trypanosoma cruzi in the Caatinga area colonised by Triatoma brasiliensis

The role played by different mammal species in the maintenance of Trypanosoma cruzi is not constant and varies in time and place. This study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of T. cruzi in Tauá, state of Ceará, Caatinga area, Brazil, with an emphasis on those environments colonised by Triatoma brasiliensis. Direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and outdoor mammals and multiplex polymerase chain reaction was used on wild mammals. Cytochrome b was used as a food source for wild insects. The serum prevalence in dogs was 38% (20/53), while in pigs it was 6% (2/34). The percentages of the most abundantly infected wild animals were as follows: Thrichomys laurentius 74% (83/112) and Kerodon rupestris 10% (11/112). Of the 749 triatomines collected in the household research, 49.3% (369/749) were positive for T. brasiliensis, while 6.8% were infected with T. cruzi (25/369). In captured animals, T. brasiliensis shares a natural environment with T. laurentius, K. rupestris, Didelphis albiventris, Monodelphis domestica, Galea spixii, Wiedomys pyrrhorhinos, Conepatus semistriatus and Mus musculus. In animals identified via their food source, T. brasiliensis shares a natural environment with G. spixii, K. rupestris, Capra hircus, Gallus gallus, Tropidurus oreadicus and Tupinambis merianae. The high prevalence of T. cruzi in household and peridomiciliar animals reinforces the narrow relationship between the enzootic cycle and humans in environments with T. brasiliensis and characterises it as ubiquitous.

The history of Chagas disease

The ancestor of Trypanosome cruzi was probably introduced to South American via bats approximately 7-10 million years ago. When the first humans arrived in the New World, a sylvatic cycle of Chagas disease was then already well established. Paleoparasitological data suggests that human American trypanosomiasis originated in the Andean area when people founded the first settlements in the coastal region of the Atacama Desert. Identification of T. cruzi as the etiological agent and triatome bugs as the transmission vector of Chagas disease occurred within a few years at the beginning of the 20th century. History also teaches us that human activity leading to environmental changes, in particular deforestation, is the main cause for the spread of Chagas disease. Recently, migration of T. cruzi-infected patients has led to a distribution of Chagas disease from Latin America to non-endemic countries in Europe, North America and western Pacific region.

Seroprevalence of T. cruzi infection in blood donors and Chagas cardiomyopathy in patients from the coal mining region of Coahuila, Mexico

Context and Objective: Chagas disease is considered a worldwide emerging disease; it is endemic in Mexico and the state of Coahuila and is considered of little relevance. The objective of this study was to determine the seroprevalence of T. cruzi infection in blood donors and Chagas cardiomyopathy in patients from the coal mining region of Coahuila, Mexico.

Design and Setting: Epidemiological, exploratory and prospective study in a general hospital during the period January to June 2011.

Methods: We performed laboratory tests ELISA and indirect hemagglutination in three groups of individuals: 1) asymptomatic voluntary blood donors, 2) patients hospitalized in the cardiology department and 3) patients with dilated cardiomyopathy.

Results: There were three levels of seroprevalence: 0.31% in asymptomatic individuals, 1.25% in cardiac patients and in patients with dilated cardiomyopathy in 21.14%.

Conclusions: In spite of having detected autochthonous cases of Chagas disease, its importance to local public health remains to be established as well as the details of the dynamics of transmission so that the study is still in progress.

Studies on protozoa in ancient remains--a review

Paleoparasitological research has made important contributions to the understanding of parasite evolution and ecology. Although parasitic protozoa exhibit a worldwide distribution, recovering these organisms from an archaeological context is still exceptional and relies on the availability and distribution of evidence, the ecology of infectious diseases and adequate detection techniques. Here, we present a review of the findings related to protozoa in ancient remains, with an emphasis on their geographical distribution in the past and the methodologies used for their retrieval. The development of more sensitive detection methods has increased the number of identified parasitic species, promising interesting insights from research in the future.

Transmission and epidemiology of zoonotic protozoal diseases of companion animals

Over 77 million dogs and 93 million cats share our households in the United States. Multiple studies have demonstrated the importance of pets in their owners' physical and mental health. Given the large number of companion animals in the United States and the proximity and bond of these animals with their owners, understanding and preventing the diseases that these companions bring with them are of paramount importance. Zoonotic protozoal parasites, including toxoplasmosis, Chagas' disease, babesiosis, giardiasis, and leishmaniasis, can cause insidious infections, with asymptomatic animals being capable of transmitting disease. Giardia and Toxoplasma gondii, endemic to the United States, have high prevalences in companion animals. Leishmania and Trypanosoma cruzi are found regionally within the United States. These diseases have lower prevalences but are significant sources of human disease globally and are expanding their companion animal distribution. Thankfully, healthy individuals in the United States are protected by intact immune systems and bolstered by good nutrition, sanitation, and hygiene. Immunocompromised individuals, including the growing number of obese and/or diabetic people, are at a much higher risk of developing zoonoses. Awareness of these often neglected diseases in all health communities is important for protecting pets and owners. To provide this awareness, this review is focused on zoonotic protozoal mechanisms of virulence, epidemiology, and the transmission of pathogens of consequence to pet owners in the United States.

Current understanding of immunity to Trypanosoma cruzi infection and pathogenesis of Chagas disease

Chagas disease caused by Trypanosoma cruzi remains an important neglected tropical disease and a cause of significant morbidity and mortality. No longer confined to endemic areas of Latin America, it is now found in non-endemic areas due to immigration. The parasite may persist in any tissue, but in recent years, there has been increased recognition of adipose tissue both as an early target of infection and a reservoir of chronic infection. The major complications of this disease are cardiomyopathy and megasyndromes involving the gastrointestinal tract. The pathogenesis of Chagas disease is complex and multifactorial involving many interactive pathways. The significance of innate immunity, including the contributions of cytokines, chemokines, reactive oxygen species, and oxidative stress, has been emphasized. The role of the components of the eicosanoid pathway such as thromboxane A(2) and the lipoxins has been demonstrated to have profound effects as both pro- and anti-inflammatory factors. Additionally, we discuss the vasoconstrictive actions of thromboxane A(2) and endothelin-1 in Chagas disease. Human immunity to T. cruzi infection and its role in pathogen control and disease progression have not been fully investigated. However, recently, it was demonstrated that a reduction in the anti-inflammatory cytokine IL-10 was associated with clinically significant chronic chagasic cardiomyopathy.

Chagas heart disease: report on recent developments

Chagas disease, caused by the parasite Trypanosoma cruzi, is an important cause of cardiac disease in endemic areas of Latin America. It is now being diagnosed in nonendemic areas because of immigration. Typical cardiac manifestations of Chagas disease include dilated cardiomyopathy, congestive heart failure, arrhythmias, cardioembolism, and stroke. Clinical and laboratory-based research to define the pathology resulting from T. cruzi infection has shed light on many of the cellular and molecular mechanisms leading to these manifestations. Antiparasitic treatment may not be appropriate for patients with advanced cardiac disease. Clinical management of Chagas heart disease is similar to that used for cardiomyopathies caused by other processes. Cardiac transplantation has been successfully performed in a small number of patients with Chagas heart disease.

Reorganization of extracellular matrix in placentas from women with asymptomatic chagas disease: mechanism of parasite invasion or local placental defense?

Chagas disease, produced by the protozoan Trypanosoma cruzi (T. cruzi), is one of the most frequent endemic diseases in Latin America. In spite the fact that in the past few years T. cruzi congenital transmission has become of epidemiological importance, studies about this mechanism of infection are scarce. In order to explore some morphological aspects of this infection in the placenta, we analyzed placentas from T. cruzi-infected mothers by immunohistochemical and histochemical methods. Infection in mothers, newborns, and placentas was confirmed by PCR and by immunofluorescence in the placenta. T. cruzi-infected placentas present destruction of the syncytiotrophoblast and villous stroma, selective disorganization of the basal lamina, and disorganization of collagen I in villous stroma. Our results suggest that the parasite induces reorganization of this tissue component and in this way may regulate both inflammatory and immune responses in the host. Changes in the ECM of placental tissues, together with the immunological status of mother and fetus, and parasite load may determine the probability of congenital transmission of T. cruzi.

Chagas disease in prehistory

The classical hypothesis proposes that Chagas disease has been originated in the Andean region among prehistoric people when they started domesticating animals, changing to sedentary habits, and adopting agriculture. These changes in their way of life happened nearly 6,000 years ago. However, paleoparasitological data based on molecular tools showed that Trypanosoma cruzi infection and Chagas disease were commonly found both in South and North American prehistoric populations long before that time, suggesting that Chagas disease may be as old as the human presence in the American continent. The study of the origin and dispersion of Trypanosoma cruzi infection among prehistoric human populations may help in the comprehension of the clinical and epidemiological questions on Chagas disease that still remain unanswered.

Pathogenesis of chagas' disease: parasite persistence and autoimmunity

Acute Trypanosoma cruzi infections can be asymptomatic, but chronically infected individuals can die of Chagas' disease. The transfer of the parasite mitochondrial kinetoplast DNA (kDNA) minicircle to the genome of chagasic patients can explain the pathogenesis of the disease; in cases of Chagas' disease with evident cardiomyopathy, the kDNA minicircles integrate mainly into retrotransposons at several chromosomes, but the minicircles are also detected in coding regions of genes that regulate cell growth, differentiation, and immune responses. An accurate evaluation of the role played by the genotype alterations in the autoimmune rejection of self-tissues in Chagas' disease is achieved with the cross-kingdom chicken model system, which is refractory to T. cruzi infections. The inoculation of T. cruzi into embryonated eggs prior to incubation generates parasite-free chicks, which retain the kDNA minicircle sequence mainly in the macrochromosome coding genes. Crossbreeding transfers the kDNA mutations to the chicken progeny. The kDNA-mutated chickens develop severe cardiomyopathy in adult life and die of heart failure. The phenotyping of the lesions revealed that cytotoxic CD45, CD8(+) γδ, and CD8α(+) T lymphocytes carry out the rejection of the chicken heart. These results suggest that the inflammatory cardiomyopathy of Chagas' disease is a genetically driven autoimmune disease.

Chagas disease: coming to a place near you

Chagas disease, or American trypanosomiasis, is a parasitic infection caused by the flagellate protozoan Trypanosoma cruzi, an organism that is endemic to Latin America. While Chagas disease is primarily a vector-borne illness, new cases are emerging in non-endemic areas due to globalization of immigration and non-vectorial transmission routes. This article discusses the mode of transmission, evolving epidemiology, pathogenesis, diagnosis, treatment and prevention and control of the disease.

Natural products and Chagas' disease: a review of plant compounds studied for activity against Trypanosoma cruzi

Here, we review studies that have investigated the activity of plant-derived compounds against Trypanosoma cruzi, the etiologic agent of Chagas’ disease. In the last decade, more than 300 species belonging to almost 100 families have been evaluated for activity, and here we describe the compounds isolated; 85 references are cited.

Epidemiology of American trypanosomiasis (Chagas disease)

Trypanosoma cruzi, the cause of American trypanosomiasis, or Chagas disease, is a protozoan parasite that is enzootic and endemic in much of the Americas, where it infects a wide variety of wild and domestic mammals as well as many species of triatomine vectors, in addition to humans. Historically, vector-borne transmission of T. cruzi has been the most important mechanism through which humans have become infected with the parasite, but transmission by blood transfusion and congenital transmission also have been important. In many of the endemic countries transmission of T. cruzi has improved markedly in recent years as vector control and donor screening programs have been implemented on a widespread basis. In the United States autochthonous transmission of T. cruzi appears to be extremely rare. Five persons are known to have become infected with T. cruzi through organ transplants here, and prior to the implementation of blood donor screening in 2007 five instances of transmission by transfusion had been reported. Current estimates put the total number of T. cruzi-infected persons living in the United States at 300,000, essentially all of whom are immigrants from the endemic countries. The obstacles that stand in the way of the total elimination of T. cruzi transmission throughout the endemic range are economic and political, and no major technological advances are needed to accomplish this goal.

Trypanosomiasis, cardiomyopathy and the risk of ischemic stroke

American (Chagas disease) and African (sleeping sickness) trypanosomiasis are neglected tropical diseases and are a heavy burden in Latin America and Africa, respectively. Chagas disease is an independent risk factor for stroke. Apical aneurysm, heart failure and cardiac arrhythmias are associated with ischemic stroke in chagasic cardiomyopathy. Not all chagasic patients who suffer an ischemic stroke have a severe cardiomyopathy, and stroke may be the first manifestation of Chagas disease. Cardioembolism affecting the middle cerebral artery is the most common stroke subtype. Risk of recurrence is high and careful evaluation of recurrence risk should be addressed. Repolarization changes, low voltage and prolonged QT interval are common electrocardiography alterations in human African trypanosomiasis, and can be found in more than 70% of patients. Epidemiological studies are needed to asses the risk of stroke in African trypanosomiasis perimyocarditis.

Transmission of chagas disease (American trypanosomiasis) by food

In April 2009, the centenary of the discovery of the American trypanosomiasis, or Chagas disease, was celebrated. A hundred years after the discovery, little has been invested in diagnostics and treatment because the disease affects mainly poor people in developing countries. However, some changes in the epidemiology of the disease are of great importance today. Chagas disease transmitted through food is a public health concern in all areas where there is a reservoir of Trypanosoma cruzi in wild animals (e.g., mammals and marsupials) and/or where infected triatomine bugs are in contact with human food source items (especially fruits and vegetables). Recently, several outbreaks of illness related to the ingestion of food contaminated with T. cruzi have been recorded in Brazil, Colombia, and Venezuela.