Epigenetic aging differences between Wichí and Criollos from Argentina: Insights from genomic history and ecology.

Background and objectives: Epigenetic estimators based on DNA methylation levels have emerged as promising biomarkers of human aging. These estimators exhibit natural variations across human groups, but data about indigenous populations remain underrepresented in research. This study aims to investigate differences in epigenetic estimators between two distinct human populations, both residing in the Gran Chaco region of Argentina, the Native-American Wichí, and admixed Criollos who are descendants of intermarriages between Native Americans and the first European colonizers, using a population genetic approach. Methodology: We analyzed 24 Wichí (mean age: 39.2 ± 12.9 yo) and 24 Criollos (mean age: 41.1 ± 14.0 yo) for DNA methylation levels using the Infinium MethylationEPIC (Illumina) to calculate 16 epigenetic estimators. Additionally, we examined genome-wide genetic variation using the HumanOmniExpress BeadChip (Illumina) to gain insights into the genetic history of these populations. Results: Our results indicate that Native-American Wichí are epigenetically older compared to Criollos according to five epigenetic estimators. Analyses within the Criollos population reveal that global ancestry does not influence the differences observed, while local (chromosomal) ancestry shows positive associations between specific SNPs located in genomic regions over-represented by Native-American ancestry and measures of epigenetic age acceleration (AgeAccelHannum). Furthermore, we demonstrate that differences in population ecologies also contribute to observed epigenetic differences. Conclusions and implications: Overall, our study suggests that while the genomic history may partially account for the observed epigenetic differences, non-genetic factors, such as lifestyle and ecological factors, play a substantial role in the variability of epigenetic estimators, thereby contributing to variations in human epigenetic aging.

Simultaneous use of two rapid diagnostic tests for the diagnosis of Chagas disease.

The sensitivity of rapid diagnostic tests (RDT) for Chagas disease is not great enough for their single use. The aim of this paper was to evaluate the performance of two RDTs for Chagas disease, used simultaneously. Two different RDTs (A and B) were performed in 64 and 42 serum samples that were negative and positive, respectively, by conventional serological techniques. Validity and reliability of both tests were evaluated individually and simultaneously. Sensitivity was 90.5% and 97.6%, and specificity was 100% and 93.8%, for RDT A and B, respectively. The κ statistic was 0.96. When both RDTs were used simultaneously, sensitivity was 97.4%, specificity was 100% and the discordance percentage 6.6%. The combined use of two RDTs with serum samples is an acceptable application in healthcare centres.

Desafíos de la Bioquímica en la era hipertecnológica / Challenges of Biochemistry in the hyper technological era / Desafios da Bioquímica na era da hipertecnologia

En la era hipertecnológica, ¿somos asistidos por la Tecnología o asistentes de la Tecnología? La máquina inteligente, el robot ideal, ¿puede realizar todas las tareas del laboratorio, con igual o mayor eficacia que el hombre? Creemos que no, ya que la máquina puede tener solamente "pensamiento calculador". En cambio, el hombre posee "pensamiento reflexivo" y juicio ético, que le permiten un discernimiento crítico fundamental. La máquina debe asistirnos, pero es el profesional quien debe decidir lo atinente al pre y post análisis, al control del instrumental en la fase analítica, y a la atención al paciente. La simplificación de los métodos analíticos conlleva a la realización de los análisis deslocalizados, "al lado del paciente". Los progresos técnicos como la miniaturización, la automatización y la informática favorecen el proceso de deslocalización, que puede tener lugar en unidades críticas, guardias, quirófanos o, incluso, fuera del ámbito hospitalario. La rapidez de respuesta en casos críticos puede justificar los análisis deslocalizados, pero existen claras limitaciones: Aseguramiento de la Calidad, Bioseguridad y aspectos bioéticos, respeto de la confidencialidad y capacidad para brindar información adecuada al paciente. En este contexto, es imperativo repensar las Ciencias de la Salud en la importancia de la tecnología pero, también, y sobre todo, en el factor humano y en el rol social del Bioquímico integrante del equipo de salud.

In the hyper technological era, are we assisted by technology or assistants of technology? The intelligent machine, the ideal robot can perform all tasks in the laboratory, with equal or greater efficacy than man? We think not, because the machine can only have "calculating thinking". Instead, man has "reflexive thinking" and ethical judgment, which allow a fundamental critical discernment. The machine must assist professionals, but is the professional who must decide about questions relative to pre and post analysis, control of instruments in the analytical phase, and patient care. Simplification of analytical methods leads to the realization of delocalized analysis, or "point of care". Technical advances such as miniaturization, automation and computing favour delocalized analysis, which can take place in critical units, emergencies, surgeries or even outside the hospital setting. The speed of response in critical cases can justify the delocalized analysis, but there are clear limitations: Quality Assurance, biosafety and bioethical aspects: confidentiality and ability to provide adequate information to the patient. In this context, in the Health Sciences, it is imperative to rethink the importance of technology, but also, and especially, the human factor and the social role of the Biochemist as health team member.

Na era hipertecnológica, somos assistidos pela Tecnologia ou assistentes da Tecnologia? A máquina inteligente, o robô ideal: pode realizar todas as tarefas de laboratório com igual ou maior eficiência do que o homem? Acreditamos que não, visto que a máquina só pode ter "pensamento calculador". Contudo, o homem possui "pensamento reflexivo" e juízo ético que lhe permitem um discernimento crítico fundamental. A máquina deve assistir-nos, porém, é o profissional quem deve tomar as decisões a respeito das pré e pós-análises, do controle do instrumental na fase analítica e do atendimento do paciente. A simplificação dos métodos analíticos conduz à realização das análises deslocadas, "ao lado do paciente". Os avanços técnicos como a miniaturização, a automação e a informática favorecem o processo de deslocação que pode ter lugar em unidades críticas, plantões, salas de cirurgia, ou até mesmo, fora do ambiente hospitalar. A velocidade de resposta em casos críticos pode justificar as análises deslocadas, porém existem claras limitações: segurança na Qualidade, Biossegurança e aspectos bioéticos; a respeito da confidencialidade e capacidade para fornecer ao paciente informação adequada. Nesse contexto, é imperativo repensar as Ciências da Saúde não só na importância da Tecnologia, mas também, e principalmente, no fator humano e no papel social do Bioquímico como integrante da equipe de saúde.

Diagnostic reliability of an immunochromatographic test for Chagas disease screening at a primary health care centre in a rural endemic area.

Many patients with Chagas disease live in remote communities that lack both equipment and trained personnel to perform a diagnosis by conventional serology (CS). Thus, reliable tests suitable for use under difficult conditions are required. In this study, we evaluated the ability of personnel with and without laboratory skills to perform immunochromatographic (IC) tests to detect Chagas disease at a primary health care centre (PHCC). We examined whole blood samples from 241 patients and serum samples from 238 patients. Then, we calculated the percentage of overall agreement (POA) between the two groups of operators for the sensitivity (S), specificity (Sp) and positive (PPV) and negative (NPV) predictive values of IC tests compared to CS tests. We also evaluated the level of agreement between ELISAs and indirect haemagglutination (IHA) tests. The readings of the IC test results showed 100% agreement (POA = 1). The IC test on whole blood showed the following values: S = 87.3%; Sp = 98.8%; PPV = 96.9% and NPV = 95.9%. Additionally, the IC test on serum displayed the following results: S = 95.7%; Sp = 100%; PPV = 100% and NPV = 98.2%. Using whole blood, the agreement with ELISA was 96.3% and the agreement with IHA was 94.1%. Using serum, the agreement with ELISA was 97.8% and the agreement with IHA was 96.6%. The IC test performance with serum samples was excellent and demonstrated its usefulness in a PHCC with minimal equipment. If the IC test S value and NPV with whole blood are improved, then this test could also be used in areas lacking laboratories or specialised personnel.

Diagnostic reliability of an immunochromatographic test for Chagas disease screening at a primary health care centre in a rural endemic area

Many patients with Chagas disease live in remote communities that lack both equipment and trained personnel to perform a diagnosis by conventional serology (CS). Thus, reliable tests suitable for use under difficult conditions are required. In this study, we evaluated the ability of personnel with and without laboratory skills to perform immunochromatographic (IC) tests to detect Chagas disease at a primary health care centre (PHCC). We examined whole blood samples from 241 patients and serum samples from 238 patients. Then, we calculated the percentage of overall agreement (POA) between the two groups of operators for the sensitivity (S), specificity (Sp) and positive (PPV) and negative (NPV) predictive values of IC tests compared to CS tests. We also evaluated the level of agreement between ELISAs and indirect haemagglutination (IHA) tests. The readings of the IC test results showed 100% agreement (POA = 1). The IC test on whole blood showed the following values: S = 87.3%; Sp = 98.8%; PPV = 96.9% and NPV = 95.9%. Additionally, the IC test on serum displayed the following results: S = 95.7%; Sp = 100%; PPV = 100% and NPV = 98.2%. Using whole blood, the agreement with ELISA was 96.3% and the agreement with IHA was 94.1%. Using serum, the agreement with ELISA was 97.8% and the agreement with IHA was 96.6%. The IC test performance with serum samples was excellent and demonstrated its usefulness in a PHCC with minimal equipment. If the IC test S value and NPV with whole blood are improved, then this test could also be used in areas lacking laboratories or specialised personnel.

Estudio comparativo de dos métodos para la cuantificación del antígeno carcinoembrionario / Comparative study of two methods for carcinoembryonic antigen quantification / Estudo comparativo de dois métodos para a quantificação do antígeno carcinoembrionário

El antígeno carcinoembrionario (CEA) es una glicoproteína ampliamente utilizada como complemento del diagnóstico, monitoreo de tratamiento y evolución del cáncer colorrectal. El objetivo del presente trabajo fue realizar un análisis comparativo entre dos métodos para la determinación de CEA: electroquimioluminiscencia y quimioluminiscencia, en muestras de suero de 57 pacientes con diagnóstico de cáncer, principalmente colorrectal. Cuando se analizaron los datos totales se obtuvo una elevada correlación (r=0,9135, p<0,00001). Al realizar un corte de los resultados tomando como límite el valor de 4 ng/mL se observó que las mayores discrepancias entre métodos estuvieron en los valores considerados dentro del rango normal (r=0,5716, p<0,0014, n=29). Por el contrario, en concentraciones mayores al límite de corte, la correlación fue elevada (r=0,9453, p<0,00001, n=28). Estos resultados sugieren que, a diferencia de lo descripto por los fabricantes, los valores de CEA obtenidos por ambos métodos son comparables. La menor correlación observada en concentraciones inferiores a 4 ng/mL no sería tan relevante debido a que estos niveles se consideran dentro del rango de normalidad y, por lo tanto, su importancia desde el punto de vista clínico es relativa. Sin embargo, debido a que pueden detectarse con baja frecuencia diferencias individuales (atribuidas probablemente a diferencias en los epitopes detectados por cada método), para los casos con fuerte presunción clínica y un valor de CEA incongruente, se sugiere repetir la determinación por medio de otra metodología.

The carcinoembryonic antigen (CEA) is a glycoprotein widely employed in colorectal cancer, mainly as evolutive marker and as measure of therapy's ef-ficacy. The goal of this work was to perform a comparative study between two analytical methods to measure serum CEA levels: electrochemiluminescence (ECL) and chemilumines-cence (CL) in serum samples of 57 patients with diagnosis of cancer, mainly colorectal. On the whole, an elevated correlation between ECL and CL (r=0.9135; p<0.00001) was obtained. When data was analyzed with a cut-off value of 4 ng/mL, the main discrepancy between methods occurred in the range of normal values (r=0.5716; p<0.0014; n=29). On the contrary, in concentrations higher than the cut-off, the cor-relation was very high (r=0.9453; p<0.00001; n=28). These results suggest that, in spite of the reports of manufacturers, the CEA values obtained by both methods are comparable. The lower correlation observed in values below 4 ng/mL would not be significant because those values are in the normal range and, for that reason, their clinical importance is minor. However, due to the individual differences that could be detected in some patients (probably resulting from the differences in epitopes detected by each method), in cases with strong clinical evidence without concordance with the CEA result, it could be necessary to repeat the determination using another methodology.

O antígeno carcinoembrionário (CEA) é uma glicoproteína amplamente usada como complemento do diagnóstico, monitoração de tratamento e evolução do câncer colorretal. O objetivo deste trabalho foi realizar uma análise comparativa entre dois métodos para a detecção do CEA: eletroquimioluminescência e quimio-luminescência em amostras de soro de 57 pacientes com diagnóstico de câncer, principalmente colorretal. Quando analisados os dados totais, houve uma correlação elevada (r=0,9135, p<0,00001). Quando realizado um corte dos resultados tomando como valor limite 4 ng/mL, observou-se que as maiores diferenças entre ambos os métodos estiveram nos valores considerados dentro da faixa dos valores normais (r=0,5716, p<0,0014, n=29). No entanto, nas concentrações superiores respeito do limite de corte, a correlação foi elevada (r=0,9453, p<0,00001, n=28). Estes resultados sugerem que, comparado com o descrito pelos fabricantes, os valores de CEA obtidos por ambos os métodos são comparáveis. A menor correlação observada nas concentrações inferiores a 4 ng/mL não seria tão relevante devido a que estes níveis consideram-se dentro da faixa de normalidade e, portanto, sua importância, do ponto de vista clínico, é relativa. Contudo, devido a que podem ser detectados com baixa frequência diferenças individuais (atribuídas provavelmente a diferenças nos epitopos detectados por cada método), para os casos com forte suspeita clínica e um valor de CEA incongruente, sugere-se repetir a determinação através de outra metodologia.

Estudio comparativo de dos métodos para la cuantificación del antígeno carcinoembrionario / Comparative study of two methods for carcinoembryonic antigen quantification / Estudo comparativo de dois métodos para a quantificaþÒo do antígeno carcinoembrionário

El antígeno carcinoembrionario (CEA) es una glicoproteína ampliamente utilizada como complemento del diagnóstico, monitoreo de tratamiento y evolución del cáncer colorrectal. El objetivo del presente trabajo fue realizar un análisis comparativo entre dos métodos para la determinación de CEA: electroquimioluminiscencia y quimioluminiscencia, en muestras de suero de 57 pacientes con diagnóstico de cáncer, principalmente colorrectal. Cuando se analizaron los datos totales se obtuvo una elevada correlación (r=0,9135, p<0,00001). Al realizar un corte de los resultados tomando como límite el valor de 4 ng/mL se observó que las mayores discrepancias entre métodos estuvieron en los valores considerados dentro del rango normal (r=0,5716, p<0,0014, n=29). Por el contrario, en concentraciones mayores al límite de corte, la correlación fue elevada (r=0,9453, p<0,00001, n=28). Estos resultados sugieren que, a diferencia de lo descripto por los fabricantes, los valores de CEA obtenidos por ambos métodos son comparables. La menor correlación observada en concentraciones inferiores a 4 ng/mL no sería tan relevante debido a que estos niveles se consideran dentro del rango de normalidad y, por lo tanto, su importancia desde el punto de vista clínico es relativa. Sin embargo, debido a que pueden detectarse con baja frecuencia diferencias individuales (atribuidas probablemente a diferencias en los epitopes detectados por cada método), para los casos con fuerte presunción clínica y un valor de CEA incongruente, se sugiere repetir la determinación por medio de otra metodología.(AU)

The carcinoembryonic antigen (CEA) is a glycoprotein widely employed in colorectal cancer, mainly as evolutive marker and as measure of therapys ef-ficacy. The goal of this work was to perform a comparative study between two analytical methods to measure serum CEA levels: electrochemiluminescence (ECL) and chemilumines-cence (CL) in serum samples of 57 patients with diagnosis of cancer, mainly colorectal. On the whole, an elevated correlation between ECL and CL (r=0.9135; p<0.00001) was obtained. When data was analyzed with a cut-off value of 4 ng/mL, the main discrepancy between methods occurred in the range of normal values (r=0.5716; p<0.0014; n=29). On the contrary, in concentrations higher than the cut-off, the cor-relation was very high (r=0.9453; p<0.00001; n=28). These results suggest that, in spite of the reports of manufacturers, the CEA values obtained by both methods are comparable. The lower correlation observed in values below 4 ng/mL would not be significant because those values are in the normal range and, for that reason, their clinical importance is minor. However, due to the individual differences that could be detected in some patients (probably resulting from the differences in epitopes detected by each method), in cases with strong clinical evidence without concordance with the CEA result, it could be necessary to repeat the determination using another methodology.(AU)

O antígeno carcinoembrionário (CEA) é uma glicoproteína amplamente usada como complemento do diagnóstico, monitoraþÒo de tratamento e evoluþÒo do cÔncer colorretal. O objetivo deste trabalho foi realizar uma análise comparativa entre dois métodos para a detecþÒo do CEA: eletroquimioluminescÛncia e quimio-luminescÛncia em amostras de soro de 57 pacientes com diagnóstico de cÔncer, principalmente colorretal. Quando analisados os dados totais, houve uma correlaþÒo elevada (r=0,9135, p<0,00001). Quando realizado um corte dos resultados tomando como valor limite 4 ng/mL, observou-se que as maiores diferenþas entre ambos os métodos estiveram nos valores considerados dentro da faixa dos valores normais (r=0,5716, p<0,0014, n=29). No entanto, nas concentraþ§es superiores respeito do limite de corte, a correlaþÒo foi elevada (r=0,9453, p<0,00001, n=28). Estes resultados sugerem que, comparado com o descrito pelos fabricantes, os valores de CEA obtidos por ambos os métodos sÒo comparáveis. A menor correlaþÒo observada nas concentraþ§es inferiores a 4 ng/mL nÒo seria tÒo relevante devido a que estes níveis consideram-se dentro da faixa de normalidade e, portanto, sua importÔncia, do ponto de vista clínico, é relativa. Contudo, devido a que podem ser detectados com baixa frequÛncia diferenþas individuais (atribuídas provavelmente a diferenþas nos epitopos detectados por cada método), para os casos com forte suspeita clínica e um valor de CEA incongruente, sugere-se repetir a determinaþÒo através de outra metodologia.(AU)

Analysis of population substructure in two sympatric populations of Gran Chaco, Argentina.

Sub-population structure and intricate kinship dynamics might introduce biases in molecular anthropology studies and could invalidate the efforts to understand diseases in highly admixed populations. In order to clarify the previously observed distribution pattern and morbidity of Chagas disease in Gran Chaco, Argentina, we studied two populations (Wichí and Criollos) recruited following an innovative bio-cultural model considering their complex cultural interactions. By reconstructing the genetic background and the structure of these two culturally different populations, the pattern of admixture, the correspondence between genealogical and genetic relationships, this integrated perspective had the power to validate data and to link the gap usually relying on a singular discipline. Although Wichí and Criollos share the same area, these sympatric populations are differentiated from the genetic point of view as revealed by Non Recombinant Y Chromosome genotyping resulting in significantly high Fst values and in a lower genetic variability in the Wichí population. Surprisingly, the Amerindian and the European components emerged with comparable amounts (20%) among Criollos and Wichí respectively. The detailed analysis of mitochondrial DNA showed that the two populations have as much as 87% of private haplotypes. Moreover, from the maternal perspective, despite a common Amerindian origin, an Andean and an Amazonian component emerged in Criollos and in Wichí respectively. Our approach allowed us to highlight that quite frequently there is a discrepancy between self-reported and genetic kinship. Indeed, if self-reported identity and kinship are usually utilized in population genetics as a reliable proxy for genetic identity and parental relationship, in our model populations appear to be the result not only and not simply of the genetic background but also of complex cultural determinants. This integrated approach paves the way to a rigorous reconstruction of demographic and cultural history as well as of bioancestry and propensity to diseases of Wichí and Criollos.

Chagas en comunidades originarias del Monte Impenetrable chaqueño, Argentina / Chagas disease in indigenous communities of the Impenetrable Chaqueño Forest

Se demuestra la elevada prevalencia de Chagas en comunidades wichi y criolla de una zona del Gran Chaco argentino, resaltando la necesidad de un control sustentable y continuo

Vaccination with Trypanosoma rangeli modulates the profiles of immunoglobulins and IL-6 at local and systemic levels in the early phase of Trypanosoma cruzi experimental infection.

In America, there are two species of Trypanosoma that can infect humans: Trypanosoma cruzi, which is responsible for Chagas disease and Trypanosoma rangeli, which is not pathogenic. We have developed a model of vaccination in mice with T. rangeli epimastigotes that protects against T. cruzi infection. The goal of this work was to study the pattern of specific immunoglobulins in the peritoneum (the site of infection) and in the sera of mice immunized with T. rangeli before and after challenge with T. cruzi. Additionally, we studied the effects triggered by antigen-antibodies binding and the levels of key cytokines involved in the humoral response, such as IL-4, IL-5 and IL-6. The immunization triggered the production of antibodies reactive with T. cruzi in peritoneal fluid (PF) and in serum, mainly IgG1 and, to a lesser magnitude, IgG2. Only immunized mice developed specific IgG3 antibodies in their peritoneal cavities. Antibodies were able to bind to the surface of the parasites and agglutinate them. Among the cytokines studied, IL-6 was elevated in PF during early infection, with higher levels in non-immunized-infected mice. The results indicate that T. rangeli vaccination against T. cruzi infection triggers a high production of specific IgG isotypes in PF and sera before infection and modulates the levels of IL-6 in PF in the early periods of infection.

Vaccination with Trypanosoma rangeli modulates the profiles of immunoglobulins and IL-6 at local and systemic levels in the early phase of Trypanosoma cruzi experimental infection

In America, there are two species of Trypanosoma that can infect humans: Trypanosoma cruzi, which is responsible for Chagas disease and Trypanosoma rangeli, which is not pathogenic. We have developed a model of vaccination in mice with T. rangeli epimastigotes that protects against T. cruzi infection. The goal of this work was to study the pattern of specific immunoglobulins in the peritoneum (the site of infection) and in the sera of mice immunized with T. rangeli before and after challenge with T. cruzi. Additionally, we studied the effects triggered by antigen-antibodies binding and the levels of key cytokines involved in the humoral response, such as IL-4, IL-5 and IL-6. The immunization triggered the production of antibodies reactive with T. cruzi in peritoneal fluid (PF) and in serum, mainly IgG1 and, to a lesser magnitude, IgG2. Only immunized mice developed specific IgG3 antibodies in their peritoneal cavities. Antibodies were able to bind to the surface of the parasites and agglutinate them. Among the cytokines studied, IL-6 was elevated in PF during early infection, with higher levels in non-immunized-infected mice. The results indicate that T. rangeli vaccination against T. cruzi infection triggers a high production of specific IgG isotypes in PF and sera before infection and modulates the levels of IL-6 in PF in the early periods of infection.

Chagas disease: serological and electrocardiographic studies in Wichi and Creole communities of Misión Nueva Pompeya, Chaco, Argentina.

Chagas disease, which is caused by Trypanosoma cruzi, affects nearly 16 million people in Latin America and causes 75-90 million people to be at risk of infection. The disease is urbanizing and globalizing due to frequent migrations. There are regions of high prevalence of infection, including the north-eastern provinces of Argentina and the entire phytogeographic region known as the Gran Chaco. In the province of Chaco, Argentina, there are places inhabited by native populations such as the Wichi and Toba communities, among others. Many Creole populations resulting from miscegenation with European colonists and immigrants coexist within these communities. It has been widely accepted that in the chronic phase of the disease, between 25-30% of individuals develop some form of cardiac disease, with the right bundle-branch block being the most typical condition described so far. The aim of this work was to study the prevalence of Chagas infection and its electrocardiographic profile in the Wichi and Creole populations of Misión Nueva Pompeya, in the area known as Monte Impenetrable in Chaco, to determine the prevalence and the pattern of heart diseases produced by Chagas disease in this region.

Chagas disease: serological and electrocardiographic studies in Wichi and Creole communities of Misión Nueva Pompeya, Chaco, Argentina

Chagas disease, which is caused by Trypanosoma cruzi, affects nearly 16 million people in Latin America and causes 75-90 million people to be at risk of infection. The disease is urbanizing and globalizing due to frequent migrations. There are regions of high prevalence of infection, including the north-eastern provinces of Argentina and the entire phytogeographic region known as the Gran Chaco. In the province of Chaco, Argentina, there are places inhabited by native populations such as the Wichi and Toba communities, among others. Many Creole populations resulting from miscegenation with European colonists and immigrants coexist within these communities. It has been widely accepted that in the chronic phase of the disease, between 25-30 percent of individuals develop some form of cardiac disease, with the right bundle-branch block being the most typical condition described so far. The aim of this work was to study the prevalence of Chagas infection and its electrocardiographic profile in the Wichi and Creole populations of Misión Nueva Pompeya, in the area known as Monte Impenetrable in Chaco, to determine the prevalence and the pattern of heart diseases produced by Chagas disease in this region.

American tripanosomiasis: a study on the prevalence of Trypanosoma cruzi and Trypanosoma cruzi-like organisms in wild rodents in San Luis province, Argentina.

INTRODUCTION: Chagas disease is caused by Trypanosoma cruzi. Wild and perianthropic mammals maintain the infection/transmission cycle, both in their natural habitat and in the peridomestic area. The aim of this paper was to present the results from a study on wild rodents in the central and northern regions of San Luis province, Argentina, in order to evaluate the prevalence of this infection. METHODS: Sherman traps were set up in capture areas located between latitudes 32 masculine and 33 masculine S, and longitudes 65 masculine and 66 masculine W. The captured rodents were taxonomically identified and hemoflagellates were isolated. Morphological, biometric and molecular studies and in vitro cultures were performed. Infection of laboratory animals and histological examination of the cardiac muscle and inoculation area were also carried out. Parasites were detected in circulating blood in Calomys musculinus, Graomys griseoflavus, Phyllotis darwini and Akodon molinae. The parasites were identified using biological criteria. Molecular PCR studies were performed on some isolates, which confirmed the characterization of these hemoflagellates as Trypanosoma cruzi. RESULTS AND CONCLUSIONS: Forty-four percent of the 25 isolates were identified as Trypanosoma cruzi, and the remaining 56% as Trypanosoma cruzi-like. These findings provide evidence that wild rats infected with Trypanosoma cruzi and Trypanosoma cruzi-like organisms are important in areas of low endemicity.

American tripanosomiasis: a study on the prevalence of Trypanosoma cruzi and Trypanosoma cruzi-like organisms in wild rodents in San Luis province, Argentina / Tripanosomiasis americana: um estudo sobre a prevalência do Trypanosoma cruzi e Trypanosoma cruzi-like em roedores silvestres da provincia de San Luis, Argentina

INTRODUCTION: Chagas disease is caused by Trypanosoma cruzi. Wild and perianthropic mammals maintain the infection/transmission cycle, both in their natural habitat and in the peridomestic area. The aim of this paper was to present the results from a study on wild rodents in the central and northern regions of San Luis province, Argentina, in order to evaluate the prevalence of this infection. METHODS: Sherman traps were set up in capture areas located between latitudes 32º and 33º S, and longitudes 65º and 66º W. The captured rodents were taxonomically identified and hemoflagellates were isolated. Morphological, biometric and molecular studies and in vitro cultures were performed. Infection of laboratory animals and histological examination of the cardiac muscle and inoculation area were also carried out. Parasites were detected in circulating blood in Calomys musculinus, Graomys griseoflavus, Phyllotis darwini and Akodon molinae. The parasites were identified using biological criteria. Molecular PCR studies were performed on some isolates, which confirmed the characterization of these hemoflagellates as Trypanosoma cruzi. RESULTS AND CONCLUSIONS: Forty-four percent of the 25 isolates were identified as Trypanosoma cruzi, and the remaining 56 percent as Trypanosoma cruzi-like. These findings provide evidence that wild rats infected with Trypanosoma cruzi and Trypanosoma cruzi-like organisms are important in areas of low endemicity.

INTRODUÇÃO: A doença de Chagas é causada pelo Trypanosoma cruzi e os mamíferos periantrópicos e silvestres mantêm o ciclo de infecção/transmissão, tanto no ambiente natural, como no peridomicílio. O objetivo deste trabalho foi mostrar os resultados de um estudo de roedores silvestres do centro e norte da Província de San Luis, Argentina, para avaliar a prevalência da infecção. MÉTODOS: Estabeleceram-se lugares de caça com armadilhas tipo Sherman entre os 32º - 33º de latitude S e 65º - 66º de longitude W. Identificou-se taxonomicamente os roedores, isolou-se os hemoflagelados e fizeram-se estudos morfológicos, biométricos, moleculares, cultivo in vitro, infecção a animais de laboratório, histologia de músculo cardíaco e de zona de inoculação. Observou-se parasitas em sangue circulante: Calomys musculinus, Graomys griseoflavus, Phyllotis darwini e Akodon molinae. A identificação dos parasitas foi feita utilizando critérios biológicos e, em alguns, realizou estudos moleculares por PCR que confirmaram a caracterização desses hemoflagelados como Trypanosoma cruzi. RESULTADOS E CONCLUSÕES: Dos 25 isolados, 44 por cento foram identificados como Trypanosoma cruzi e 56 por cento como Trypanosoma cruzi like. Este achado nos induz a considerar a importância dos ratos do mato infectados com Trypanosoma cruzi y Trypanosoma cruzi like, em área de baixa endemicidade.