Correction: Vector mapping and bloodmeal metabarcoding demonstrate risk of urban Chagas disease transmission in Caracas, Venezuela.

[This corrects the article DOI: 10.1371/journal.pntd.0010613.].

Vector mapping and bloodmeal metabarcoding demonstrate risk of urban Chagas disease transmission in Caracas, Venezuela.

Chagas disease is a significant public health risk in rural and semi-rural areas of Venezuela. Triatomine infection by the aetiological agent Trypanosoma cruzi is also observed in the Metropolitan District of Caracas (MDC), where foodborne T. cruzi outbreaks occasionally occur but active vector-to-human transmission (infection during triatomine bloodmeal) is considered absent. Citizen science-based domiciliary triatomine collection carried out between 2007 and 2013 in the MDC has advanced understanding of urban T. cruzi prevalence patterns and represents an important public awareness-building tool. The present study reports on the extension of this triatomine collection program from 2014 to 2019 and uses mitochondrial metabarcoding to assess feeding behavior in a subset of specimens. The combined, thirteen-year dataset (n = 4872) shows a high rate of T. cruzi infection (75.2%) and a predominance of Panstrongylus geniculatus (99.01%) among triatomines collected in domiciliary areas by MDC inhabitants. Collection also involved nymphal stages of P. geniculatus in 18 of 32 MDC parishes. Other collected species included Triatoma nigromaculata, Triatoma maculata, Rhodnius prolixus, and Panstrongylus rufotuberculatus. Liquid intestinal content indicative of bloodmeal was observed in 53.4% of analyzed specimens. Dissection pools representing 108 such visually blooded P. geniculatus specimens predominantly tested positive for human cytochrome b DNA (22 of 24 pools). Additional bloodmeal sources detected via metabarcoding analysis included key sylvatic T. cruzi reservoirs (opossum and armadillo), rodents, and various other synanthropic and domesticated animals. Results suggest a porous sylvatic-domiciliary transmission interface and ongoing adaptation of P. geniculatus to the urban ecotope. Although P. geniculatus defecation traits greatly limit the possibility of active T. cruzi transmission for any individual biting event, the cumulation of this low risk across a vast metropolitan population warrants further investigation. Efforts to prevent triatomine contact with human food sources also clearly require greater attention to protect Venezuela's capital from Chagas disease.

Intraspecific and Interspecific Phenotypic Differences Confirm the Absence of Cryptic Speciation in Triatoma sordida (Hemiptera, Triatominae).

Triatoma sordida is an endemic Chagas disease vector in South America, distributed in Brazil, Bolivia, Paraguay, and Uruguay. Chromosomal, molecular, isoenzymatic, and cuticular hydrocarbon pattern studies indicate cryptic speciation in T. sordida. Recently, T. rosai was described from specimens from Argentina initially characterized as T. sordida. Although several authors assume that the speciation process that supports this differentiation in T. sordida is the result of cryptic speciation, further morphological and/or morphometric studies are necessary to prove the application of this evolutionary event, because the only morphological intraspecific comparison performed in T. sordida is based on geometric morphometry and the only interspecific comparison made is between T. rosai and T. sordida from Brazil that evaluated morphological and morphometric differences. Based on this, morphological analyses of thorax and abdomen using Scanning Electron Microscopy and morphometric analyses of the head, thorax, and abdomen among T. sordida from Brazil, Bolivia, and Paraguay, as well as T. rosai, were performed to assess whether the evolutionary process responsible for variations is the cryptic speciation phenomenon. Morphological differences in the thorax and female external genitalia, as well as morphometric differences in the head, thorax, abdomen, pronotum, and scutellum structures, were observed. Based on this, the evolutionary process that supports, so far, these divergences observed for T. sordida populations/T. sordida subcomplex is not cryptic speciation. Moreover, we draw attention to the necessity for morphological/morphometric studies to correctly apply the cryptic species/speciation terms in triatomines.

Chagas Disease Vectors of Paraguay: Entomoepidemiological Aspects of Triatoma sordida (Stål, 1859) and Development of an Identification Key for Paraguayan Triatomines Based on Cytogenetics Data.

Approximately 150,000 people are living with Chagas disease in Paraguay. Although the country has been since 2008 considered as one of the countries that succeeded in interrupted the vector transmission of Chagas by Triatoma infestans in houses of the eastern region, there are nine other species notified in the country that are potential vectors and also deserve attention from vector control programs. Thus, we carried out an entomoepidemiological study of T. sordida in the eastern and western regions of the country and we developed an identification key for Paraguay's triatomines based on cytogenetic data. Between the years 2003 to 2004, 271 specimens of T. sordida were captured in domestic, peridomestic, and wild ecotopes, with 131 insects caught in the eastern (Alto Paraguay, Boquerón and Pte. Hayes) and 140 in the western region of Paraguay (Guairá and Paraguarí). High rates of peridomicillary infestation were observed for both regions. Besides that, the natural infection of the captured insects was detected by optical microscopy in 12% and 10%, and by PCR in 21% and 20% in the eastern and western regions, respectively. Based on cytogenetic data from nine of ten species notified in Paraguay, an identification key was developed to differentiate all taxa. Thus, given the vectorial importance of T. sordida, we highlight the need for continued attention from Paraguay's vector control programs for this species. Further, we provide a taxonomic key that assists in the correct classification of Paraguayan triatomines.

Repeat-Driven Generation of Antigenic Diversity in a Major Human Pathogen, Trypanosoma cruzi.

Trypanosoma cruzi, a zoonotic kinetoplastid protozoan parasite, is the causative agent of American trypanosomiasis (Chagas disease). Having a very plastic, repetitive and complex genome, the parasite displays a highly diverse repertoire of surface molecules, with pivotal roles in cell invasion, immune evasion and pathogenesis. Before 2016, the complexity of the genomic regions containing these genes impaired the assembly of a genome at chromosomal level, making it impossible to study the structure and function of the several thousand repetitive genes encoding the surface molecules of the parasite. We here describe the genome assembly of the Sylvio X10/1 genome sequence, which since 2016 has been used as a reference genome sequence for T. cruzi clade I (TcI), produced using high coverage PacBio single-molecule sequencing. It was used to analyze deep Illumina sequence data from 34 T. cruzi TcI isolates and clones from different geographic locations, sample sources and clinical outcomes. Resolution of the surface molecule gene distribution showed the unusual duality in the organization of the parasite genome, a synteny of the core genomic region with related protozoa flanked by unique and highly plastic multigene family clusters encoding surface antigens. The presence of abundant interspersed retrotransposons in these multigene family clusters suggests that these elements are involved in a recombination mechanism for the generation of antigenic variation and evasion of the host immune response on these TcI strains. The comparative genomic analysis of the cohort of TcI strains revealed multiple cases of such recombination events involving surface molecule genes and has provided new insights into T. cruzi population structure.

Culture-free genome-wide locus sequence typing (GLST) provides new perspectives on Trypanosoma cruzi dispersal and infection complexity.

Analysis of genetic polymorphism is a powerful tool for epidemiological surveillance and research. Powerful inference from pathogen genetic variation, however, is often restrained by limited access to representative target DNA, especially in the study of obligate parasitic species for which ex vivo culture is resource-intensive or bias-prone. Modern sequence capture methods enable pathogen genetic variation to be analyzed directly from host/vector material but are often too complex and expensive for resource-poor settings where infectious diseases prevail. This study proposes a simple, cost-effective 'genome-wide locus sequence typing' (GLST) tool based on massive parallel amplification of information hotspots throughout the target pathogen genome. The multiplexed polymerase chain reaction amplifies hundreds of different, user-defined genetic targets in a single reaction tube, and subsequent agarose gel-based clean-up and barcoding completes library preparation at under 4 USD per sample. Our study generates a flexible GLST primer panel design workflow for Trypanosoma cruzi, the parasitic agent of Chagas disease. We successfully apply our 203-target GLST panel to direct, culture-free metagenomic extracts from triatomine vectors containing a minimum of 3.69 pg/µl T. cruzi DNA and further elaborate on method performance by sequencing GLST libraries from T. cruzi reference clones representing discrete typing units (DTUs) TcI, TcIII, TcIV, TcV and TcVI. The 780 SNP sites we identify in the sample set repeatably distinguish parasites infecting sympatric vectors and detect correlations between genetic and geographic distances at regional (< 150 km) as well as continental scales. The markers also clearly separate TcI, TcIII, TcIV and TcV + TcVI and appear to distinguish multiclonal infections within TcI. We discuss the advantages, limitations and prospects of our method across a spectrum of epidemiological research.

Estado nutricional, síndrome metabólico e inflamación en pacientes con enfermedad de Chagas / Nutritional condition, metabolic syndrome and inflammation in patients with Chagas disease

El propósito de este estudio fue describir la asociación entre el estado nutricional, la presencia de síndrome metabólico (SM), y el estado inflamatorio, en pacientes con Enfermedad de Chagas (ECh), atendidos en la consulta externa del Instituto de Medicina Tropical en Caracas. El estudio fue de tipo transversal y correlacional, en el cual se seleccionaron 34 pacientes a los cuales se les realizó un diagnóstico parasitológico, inmunológico y molecular de la ECh. Se evaluaron variables antropométricas, clínicas y bioquímicas, así como el SM el cual fue determinado por los criterios del III Panel estadounidense para el Tratamiento de Adultos del Programa Nacional de Educación sobre el Colesterol (ATP-III, por sus siglas en inglés). Se encontró que la mayoría de los pacientes presentaron sobrepeso u obesidad (73,5%), un porcentaje de grasa corporal (% GC) alto o muy alto (82,3%), y obesidad abdominal (61,8 %). La frecuencia de SM fue de 29,4% y más del 90% mostraron valores elevados de Proteína C Reactiva ultrasensible (PCRus). Valores más elevados del IMC se asociaron con un estadio más avanzado de la ECh. Los sujetos con presencia de ADN de Tripanosoma cruzi (T. cruzi) circulante en sangre, presentaron mayor % GC, y en su mayoría, fueron diagnosticados con SM. En conclusión, los pacientes evaluados mostraron un exceso de adiposidad, que puede favorecer el estado inflamatorio, el desarrollo de SM y la progresión de la ECh(AU)

The purpose of the study was to describe the association between nutritional and inflammatory status and the presence of metabolic syndrome (MS) on patients with Chagas disease (CD) treated at the Outpatient Services of the Tropical Medicine Institute in Caracas, Venezuela. The study was cross-sectional and correlational. Thirty-four (34) patients were selected and a molecular, immunological, and parasitological diagnostic test was ran for Chagas disease. Anthropometric, clinic, and biochemical variables were evaluated, and the MS was determined using National Cholesterol Education Program Expert/Adult Treatment Panel III (ATP-III) criteria. The results showed a high percentage of patients overweight or presenting obesity (73.5%), a high and very high percentage of body fat (82.3%), and abdominal obesity (61.8%). The prevalence of MS was 29,4% and more than 90% of patients showed elevated values of high sensitivity C-reactive protein (hsCRP). Higher body-mass index values were associated with advanced stages of the CD. Subjects in the presence of T. cruzi DNA in the blood showed a greater percentage of body fat and, most of them, were diagnosed with MS. In conclusion, the evaluated patients showed an excess of adiposity which may favor an inflammatory status, the development of the MS, and the progress of the CD(AU)

Genetic diversification of Panstrongylus geniculatus (Reduviidae: Triatominae) in northern South America.

Triatomines are the vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. Although Triatoma and Rhodnius are the most-studied vector genera, other triatomines, such as Panstrongylus, also transmit T. cruzi, creating new epidemiological scenarios. Panstrongylus has at least 13 reported species but there is limited information about its intraspecific genetic variation and patterns of diversification. Here, we begin to fill this gap by studying populations of P. geniculatus from Colombia and Venezuela and including other epidemiologically important species from the region. We examined the pattern of diversification of P. geniculatus in Colombia using mitochondrial and nuclear ribosomal data. Genetic diversity and differentiation were calculated within and among populations of P. geniculatus. Moreover, we constructed maximum likelihood and Bayesian inference phylogenies and haplotype networks using P. geniculatus and other species from the genus (P. megistus, P. lignarius, P. lutzi, P. tupynambai, P. chinai, P. rufotuberculatus and P. howardi). Using a coalescence framework, we also dated the P. geniculatus lineages. The total evidence tree showed that P. geniculatus is a monophyletic species, with four clades that are concordant with its geographic distribution and are partly explained by the Andes orogeny. However, other factors, including anthropogenic and eco-epidemiological effects must be investigated to explain the existence of recent geographic P. geniculatus lineages. The epidemiological dynamics in structured vector populations, such as those found here, warrant further investigation. Extending our knowledge of P. geniculatus is necessary for the accurate development of effective strategies for the control of Chagas disease vectors.

Venezuela's humanitarian crisis, resurgence of vector-borne diseases, and implications for spillover in the region.

In the past 5-10 years, Venezuela has faced a severe economic crisis, precipitated by political instability and declining oil revenue. Public health provision has been affected particularly. In this Review, we assess the impact of Venezuela's health-care crisis on vector-borne diseases, and the spillover into neighbouring countries. Between 2000 and 2015, Venezuela witnessed a 359% increase in malaria cases, followed by a 71% increase in 2017 (411 586 cases) compared with 2016 (240 613). Neighbouring countries, such as Brazil, have reported an escalating trend of imported malaria cases from Venezuela, from 1538 in 2014 to 3129 in 2017. In Venezuela, active Chagas disease transmission has been reported, with seroprevalence in children (<10 years), estimated to be as high as 12·5% in one community tested (n=64). Dengue incidence increased by more than four times between 1990 and 2016. The estimated incidence of chikungunya during its epidemic peak is 6975 cases per 100 000 people and that of Zika virus is 2057 cases per 100 000 people. The re-emergence of many vector-borne diseases represents a public health crisis in Venezuela and has the possibility of severely undermining regional disease elimination efforts. National, regional, and global authorities must take action to address these worsening epidemics and prevent their expansion beyond Venezuelan borders.

Histopathologic study from a colorectal cancer screening in Chile: results from the first 2 years of an international collaboration between Chile and Japan.

A national colorectal cancer (CRC) screening program began in Chile in 2012, which is an international collaboration between Japan and Chile and is based on a standardized protocol supported by Tokyo Medical and Dental University. We describe the results from the first 2 years of screening at one public hospital in Punta Arenas, Chile. Of 4124 asymptomatic individuals aged between 50 and 75 years, 485 participants with immunological fecal occult blood test values of at least 100 ng/ml and/or those with family histories of CRC underwent colonoscopies. Lesions were found in 291 participants, and 642 histologic samples were obtained. Chilean pathologists made the initial histologic diagnoses, and a Japanese pathologist reviewed the histologic slides and analyzed the results. Of the 291 participants with lesions, 60 (20.6%) were diagnosed with adenocarcinomas, of which 50 (83.3%) were early-phase adenocarcinomas (pTis or pT1), and 163 (56.0%) were diagnosed with conventional adenomas, of which 96 (58.9%) were high-risk adenomas. The cancer prevalence within the screened population was 1.5% (60 of 4124). The colonoscopy cancer detection rate was 12.4% (60 of 485). Notably, we detected one flat-depressed (0-IIc) lesion that measured 5 mm and had invaded the submucosa. The findings from this screening program are the first to show the histopathologic distributions of consecutive lesions and the high incidence of CRC in Chile. The high detection rates for high-risk adenomas and cancer support the feasibility of early CRC screening and its potential to reduce the mortality associated with CRC.

Genetic variability of Panstrongylus geniculatus (Reduviidae: Triatominae) in the Metropolitan District of Caracas, Venezuela.

Panstrongylus geniculatus has become the most frequently registered vector of Chagas disease in the metropolitan area of Caracas, Venezuela. This triatomine species has invaded urban areas in recent years and has been implicated in multiple oral outbreaks of Chagas disease in the region. The study of genetic variability and spatial structure in P. geniculatus populations can provide information about possible events of domiciliation and aid intervention programs against triatomine species rapidly adapting to urban ecotopes. We sequenced a region of the cytochrome-b gene in 114 specimens of P. geniculatus from the Metropolitan District of Caracas and assessed patterns of gene flow and phylogenetic relationships among these individuals. A total of 29 haplotypes were detected in the two sampled municipalities, Sucre and Libertador. Though high genetic connectivity was observed between the municipalities (FST = 0.10796; Nm = 11.20), subtle genetic structuring was also observed in particular geographic sub regions. Based on neutrality tests and the observed allele-frequency distribution, the Panstrongylus geniculatus population appears to be expanding and adapting to different microhabitats present in the study area. Our findings affirm the capacity of this insect to adapt to different environments and emphasize its principal role in the epidemiology of Chagas disease in northern Venezuela.

A Pilot Trial to Quantify Plasma Exosomes in Colorectal Cancer Screening from the International Collaborative Study between Chile and Japan.

BACKGROUND: In Chile, a national colorectal cancer (CRC) screening program using immunochemical fecal occult blood tests and colonoscopy was started in 2012 as an international collaboration between Chile and Japan. In the present study, we quantified exosomes in the peripheral blood and evaluated the implication of the results for CRC screening. METHODS: A total of 25 peripheral plasma samples from the participants of CRC screening in Punta Arenas, Chile, were analyzed for exosomes. RESULTS: Plasma exosomes were obtained from 5 participants with adenocarcinoma (4 pTis and 1 pT1), 8 with high-grade adenoma, 4 with low-grade adenoma, 4 with hyperplastic polyps, and 4 with normal findings. Participants with adenocarcinoma had significantly higher amounts of plasma exosomes (2.1-3.2 fold) than participants with normal findings, hyperplastic polyps, or low-grade adenoma (p = 0.016, p = 0.0034, and p = 0.0042 respectively; Tukey's multiple comparisons test). The size of the representative lesion, the number of lesions, and the sum of those 2 factors in each participant correlated significantly with the exosome amounts (r = 0.56, r = 0.58, and r = 0.72, respectively; p < 0.01; Spearman's correlation coefficient test). CONCLUSIONS: This pilot study demonstrated that quantification of plasma exosomes is a potential alternative screening method for detecting individuals with a high risk of colorectal malignancy.

Panstrongylus geniculatus and four other species of triatomine bug involved in the Trypanosoma cruzi enzootic cycle: high risk factors for Chagas' disease transmission in the Metropolitan District of Caracas, Venezuela.

BACKGROUND: Chagas' disease is caused by the protozoan Trypanosoma cruzi and is autochthonous to the Americas. Its distribution depends on triatomine bugs that are responsible for the transmission of the disease. In 2005, we reported the presence of Panstrongylus geniculatus as a risk for Chagas' disease transmission in Caracas and neighboring areas. Three massive oral outbreaks occurred in the following years. Here we report the results of a 7-year study on triatomine species found in the Metropolitan District of Caracas (MDC), Venezuela. METHODS: Triatomine species collected by inhabitants of Caracas during 7 years were analyzed for parasite infection and blood meal. Triatomines were found in 31 of the 32 parishes surveyed. Traitomines were examined for the presence of blood and parasites in the digestive tract. Molecular techniques were used for the typing of parasites. RESULTS: A total of 3551 triatomines were captured from 31 of the 32 parishes surveyed. The vast majority of these were identified as P. geniculatus (98.96%), followed by Triatoma nigromaculata (0.59%), Triatoma maculata (0.39%) and Rhodnius prolixus (0.06%). Triatomines were always most abundant between April and June, and 2010 showed the highest number. We found that 54% of the specimens were females, 42.5% males and 3.5% nymphs. Overall, 75.2% of the insects were naturally infected with T. cruzi and 48.7% had fed on blood. Analysis of the adult forms showed that 60% of the females and 31.9 % of the males had blood in their stomachs, and 77.5% of the females and 73.3% of the males were naturally infected with T. cruzi. Nearly all, 99.6% of the T. cruzi isolates analyzed belonged to the TcI genotype. CONCLUSIONS: Blood-fed triatomine bugs infected with T. cruzi were distributed throughout Caracas. Four different species of triatomines were identified of which P. geniculatus was by far the most predominant. Our previous report of Eratyrus mucronatus raises the number of triatomine species in the MDC to 5. Dramatic modifications to the surrounding natural habitats have led to the establishment of a T. cruzi urban enzootic cycle, resulting in a high risk for Chagas' disease transmission in this capital city.

Genetic and Morphometric Variability of Triatoma sordida (Hemiptera: Reduviidae) from the Eastern and Western Regions of Paraguay.

Triatoma sordida is widely distributed throughout the Chaco and the Eastern Region of Paraguay. It is associated to palm trees and artificial ecotopes located in peridomestic environments. The aim of this work was to determine genetic and morphometric variability and feeding behavior among population of T. sordida captured in domicile and peridomicile areas of Paraguay. Feeding contents and levels of genetic and morphometric variation were determined in 124 T. sordida from domicile and peridomicile populations of San Pedro and Paraguarí departments of the Eastern Region and Boquerón and Presidente Hayes departments of the Western region using Double Diffusion Gel, random amplified polymorphic DNA (RAPD), and head and wings morphometry. Morphometric analysis revealed isolation of populations by geographic region and larger size in triatomine populations from the Western Region. RAPD showed no specific patterns for domicile and peridomicile populations. The estimator of diversity (F ST; 0.08) and high gene flow obtained (N m; 5.7) did not allow the establishment of genetic differentiation within the same region. The blood meal source showed that poultry feeding was 38% of host preferences, and human blood was the second feeding preference (24%) in the insects from the Eastern Region while poultry feeding was predominant in those from the Western Region (30%). This work showed homogeneity between T. sordida populations of the same region and between domicile and peridomicile. The genetic diversity was determined among T. sordida populations of both geographical regions suggesting differentiation associated to eco-geographical isolation by distance. It is important to notice that pattern feedings were different between the two regions. Further studies should be focused on how phenetic and genetic variations could be related to the adaptation capacity of these triatomine populations to domicile, increasing their vector potentiality in the transmission of Chagas disease.

Development of peptide-based lineage-specific serology for chronic Chagas disease: geographical and clinical distribution of epitope recognition.

BACKGROUND: Chagas disease, caused by infection with the protozoan Trypanosoma cruzi, remains a serious public health issue in Latin America. Genetically diverse, the species is sub-divided into six lineages, known as TcI-TcVI, which have disparate geographical and ecological distributions. TcII, TcV, and TcVI are associated with severe human disease in the Southern Cone countries, whereas TcI is associated with cardiomyopathy north of the Amazon. T. cruzi persists as a chronic infection, with cardiac and/or gastrointestinal symptoms developing years or decades after initial infection. Identifying an individual's history of T. cruzi lineage infection directly by genotyping of the parasite is complicated by the low parasitaemia and sequestration in the host tissues. METHODOLOGY/PRINCIPAL FINDINGS: We have applied here serology against lineage-specific epitopes of the T. cruzi surface antigen TSSA, as an indirect approach to allow identification of infecting lineage. Chagasic sera from chronic patients from a range of endemic countries were tested by ELISA against synthetic peptides representing lineage-specific TSSA epitopes bound to avidin-coated ELISA plates via a biotin labelled polyethylene glycol-glycine spacer to increase rotation and ensure each amino acid side chain could freely interact with their antibodies. 79/113 (70%) of samples from Brazil, Bolivia, and Argentina recognised the TSSA epitope common to lineages TcII/TcV/TcVI. Comparison with clinical information showed that a higher proportion of Brazilian TSSApep-II/V/VI responders had ECG abnormalities than non-responders (38% vs 17%; p<0.0001). Among northern chagasic sera 4/20 (20%) from Ecuador reacted with this peptide; 1/12 Venezuelan and 1/34 Colombian samples reacted with TSSApep-IV. In addition, a proposed TcI-specific epitope, described elsewhere, was demonstrated here to be highly conserved across lineages and therefore not applicable to lineage-specific serology. CONCLUSIONS/SIGNIFICANCE: These results demonstrate the considerable potential for synthetic peptide serology to investigate the infection history of individuals, geographical and clinical associations of T. cruzi lineages.

Proliferación de trypanosoma cruzi en la membrana peritoneal y líquido ascítico de ratones con infección aguda / Proliferation of trypanosoma cruzi in the peritoneal membrane and ascitic liquid of mice with acute infection

En este estudio fue analizada la parasitemia y el parasitismo en el líquido ascítico (LA), membrana peritoneal (MP) y en otros tejidos de 40 ratones machos NMRI durante la infección aguda. Los ratones (20 ratones por grupo) fueron inoculados por vía intradérmica con tripomastigotos metacíclicos linaje T.cr I de las cepas P6 y P11 obtenidos de Rhodnius prolixus. Formas delgadas y gruesas de tripomastigotos fueron encontradas en la sangre de todos los ratones. En los ratones infectados con la cepa P6 los tripomastigotos aparecieron primero en él LA a los 13 días pi y en la sangre a los 18 días pi, en los ratones infectados con la cepa P11 los parásitos se observaron primero en la sangre a los 15 días pi y en él LA a los 22 días pi. Los ratones desarrollaron emaciación, disnea, hirsutismo, pérdida de la actividad motora de las patas posteriores y hepatoesplenomegalia. Los ratones fueron sacrificados a los 39 días pi. El estudio histológico mostró que T. cruzi prolifera formando nidos de amastigotos y tripomastigotos en la MP. Los parásitos también fueron encontrados en el músculo esquelético y en el corazón de los ratones infectados con la cepa P6. La inmunotinción con PAP reveló antígeno de T. cruzi en las secciones de esófago, estómago, intestino delgado y grueso, bazo, riñón, hígado, próstata y pene de los ratones. Estos resultados confirmaron que las cepas P6 y P11 desarrollaron anormalidades histopatológicas en el tracto gastrointestinal, renal y órgano reproductivo. La localización intra-peritoneal de los parásitos y la acumulación de fluido peritoneal, reveló ascitis y peritonitis causada por el incremento de líquido en la cavidad peritoneal y destrucción del tejido peritoneal de los ratones. El presente estudio reporta por primera vez la proliferación de tripomastigotos en la cavidad peritoneal cinco días antes de encontrarse en la sangre periférica para la cepa P6 causando daño intraperitoneal y muerte del modelo murino utilizado.

In this study we analyzed the parasitemia and parasitism in the ascitic fluid (AF), peritoneal membrane (PM) and in other tissues of 40 NMRI male mice during acute infection. Mice (20 mice per group) were inoculated by intradermal route with metacyclic trypomastigotes T.cI lineage of P6 or P11 strains obtained from Rhodnius prolixus. Slender and stout forms were observed in the blood of all mice. In infected mice with P6 strain the trypomastigotes were observed first in the AF at day 13 pi and in blood at day 18 pi. Meanwhile in infected mice with P11 strain trypomastigotes were observed first in the blood at day 15 pi and in the AF at day 22 pi. Infected mice showed emaciation, dyspnea, bristled hair, loss of motor activities in the rear limbs and hepatosplenomegaly. Mice were sacrificed at day 39 pi. Histological finding indicated that T. cruzi proliferates forming amastigotes and trypomastigotes nests in the PM. Parasites were also observed in skeletal muscle of the mice and in the heart of infected mice with P6 strain. Imunostaining with PAP revealed T. cruzi antigen in esophagus, stomach, thin and thick intestine, spleen, and kidney, liver, prostate and penis. The results show that P6 and P11 colonized and produced abnormalities in the gastrointestinal tract, renal and reproductive organs. Intra-peritoneal localization of parasites and accumulation of peritoneal fluid, revealed ascites and peritonitis caused by increase of fluid in the peritoneal cavity and destruction of the membrane peritoneal of the mice. This study reports for the first time the proliferation of trypomastigotes in the peritoneal cavity five days earlier than in peripheral blood for the P6 strain causing intra-peritoneal damage and death in the murine model used.

Tripanosomiasis en el embarazo / Trypanosomiasis in pregnancy

OBJETIVO: describir la morbimortalidad materna y perinatal causada por la tripanosomiasis en las gestantes que asisten a control en el Servicio Prenatal de la Maternidad “Concepción Palacios” y al Hospital Central de Biscucuy. MÉTODOS: Se incluyó una muestra de 828 pacientes, 178 de la zona rural y 650 de la urbana. Se realizó la pesquisa para tripanosomiasis mediante prueba rápida y confirmación por serología, de las madres positivas para tripanosomiasis. Se tomó muestra de la sangre del cordón umbilical para determinar la transmisión congénita de la enfermedad. RESULTADOS: Fueron positivas para enfermedad de Chagas 6 pacientes, para una frecuencia global de 0,72 %. Cinco de las pacientes provenían de la zona rural (2,8.%) y una del medio urbano (0,15 %). Entre las 6 pacientes positivas, 83,3 % provenía de la zona rural y 16,7 % de la urbana. La serología de los recién nacidos fue positiva en cuatro casos del medio rural y un caso del medio urbano. La reacción en cadena de la polimerasa fue positiva en 2 de los 6 neonatos de madres con la enfermedad. Las pruebas parasitológicas fueron negativas en el 100.% de los neonatos en riesgo. CONCLUSIONES: La frecuencia de tripanosomiasis fue de 0,72 %. No hubo transmisión congénita de la enfermedad.

OBJECTIVE: to describe maternal and perinatal morbidity and mortality caused by trypanosomiasis in pregnant women attending prenatal control in the obstetric service of Maternidad “Concepcion Palacios” and Hospital Central de Biscucuy. METHODS: A sample of 828 patients was included from both areas, 178 in rural and 650 urban. Research was performed by rapid test for trypanosomiasis and confirmation by serology, from mothers positive for trypanosomiasis. Sample was taken from the umbilical cord blood to determine congenital transmission of the disease. RESULTS: Were positive for Chagas disease 6 patients, for an overall frequency of 0.72 %. Five of the patients were from rural areas (2.8 %) and in urban areas (0.15 %). Between 6 positive patients, 83.3 % came from rural and 16.7 % urban areas. The newborns serology was positive in four cases of rural and urban case. The chain reaction polymerase was positive in 2 of the 6 infants of mothers with the disease. Parasitological tests were negative in 100 % of infants at risk. CONCLUSIONS: The frequency of trypanosomiasis was 0.72 %. There was not congenital transmission of the disease.

Molecular epidemiologic source tracking of orally transmitted Chagas disease, Venezuela.

Oral outbreaks of Chagas disease are increasingly reported in Latin America. The transitory presence of Trypanosoma cruzi parasites within contaminated foods, and the rapid consumption of those foods, precludes precise identification of outbreak origin. We report source attribution for 2 peri-urban oral outbreaks of Chagas disease in Venezuela via high resolution microsatellite typing.

Electrocardiography repolarization abnormalities are characteristic signs of acute chagasic cardiomyopathy / Los trastornos de la repolarización ventricular son signos característicos de la cardiomiopatía chagásica aguda

Chagas disease is a tropical parasitic disease caused by the protozoan Trypanosoma cruzi (T. cruzi), whose reemergence as oral outbreaks is currently a public health problem in Venezuela. T. cruzi infection induces myocardial damage; which according to the microvascular theory, is derived from parasite-mediated disruption of the endothelium, inducing platelet aggregation and ischemia. In order to determine whether ventricular repolarization disorders observed in human patients are characteristic signs of the disease that can be reproduced in NMRI mice; we studied 12 patients with a well documented diagnosis of acute Chagas disease, based on epidemiological, clinical, parasitological and molecular data. Also, T. cruzi isolates from the blood of human patients from other Venezuelan geographical regions were characterized and inoculated in albino NMRI mice. A standard 12-lead and bipolar electrocardiogram configuration were done in human patients during the acute phase of the disease and in mice, after three weeks of infection. Results in human showed repolarization disorders, characterized by: negative, bimodal or biphasic T waves, ST segment depression or elevation and early repolarization. In mice a significant increase in T wave amplitude, increased QT interval duration and elevation or depression of ST segment were observed. These findings were evidenced in all infected mice, suggesting that electrocardiographic repolarization abnormalities in a well documented clinical and epidemiological context are signs that increase the sensitivity for the diagnosis of acute Chagas´ disease.

La enfermedad de Chagas es una hemoparasitosis causada por Trypanosoma cruzi (T. cruzi), cuya re-emergencia como epidemias por contaminación oral es actualmente un problema de salud pública en Venezuela. La infección por T. cruzi causa miocarditis; que de acuerdo con la teoría microvascular deriva del daño del endotelio vascular, al inducir agregación plaquetaria e isquemia. Con el objetivo de demostrar que los trastornos de repolarización son signos propios de la miocarditis chagásica aguda (MChA) reproducibles en modelos animales, estudiamos 12 pacientes humanos con diagnostico bien documentado de MChA, basado en datos epidemiológicos, clínicos, parasitológicos y moleculares. A partir de la sangre de los pacientes obtuvimos los aislados de T cruzi, los caracterizamos molecularmente y los inoculamos en ratones albinos NMRI; paralelamente, aislados de T cruzi provenientes de otras regiones de Venezuela fueron también ensayados. Tanto en los pacientes humanos como en los ratones con Chagas agudo, se realizaron estudios electrocardiográficos en 12 derivaciones estándares y en configuración bipolar, respectivamente. En humanos observamos trastornos de la repolarización ventricular caracterizados por: onda T negativa, bimodal o bifásica; elevación o depresión del segmento ST y despolarizaciones tempranas. En ratones observamos incrementos en la amplitud de la onda T, aumento en la duración del intervalo QT y elevación o depresión del segmento ST. Estos hallazgos fueron evidenciados en todos los ratones infectados con los diferentes aislados, sugiriendo que los trastornos de repolarización, en un adecuado y bien documentado contexto epidemiológico y clínico, son signos que aumentan la sensibilidad para el diagnóstico de MChA.

North American import? Charting the origins of an enigmatic Trypanosoma cruzi domestic genotype.

BACKGROUND: Trypanosoma cruzi, the agent of Chagas disease, is currently recognized as a complex of six lineages or Discrete Typing Units (DTU): TcI-TcVI. Recent studies have identified a divergent group within TcI - TcI(DOM). TcI(DOM). is associated with a significant proportion of human TcI infections in South America, largely absent from local wild mammals and vectors, yet closely related to sylvatic strains in North/Central America. Our aim was to examine hypotheses describing the origin of the TcI(DOM) genotype. We propose two possible scenarios: an emergence of TcI(DOM) in northern South America as a sister group of North American strain progenitors and dispersal among domestic transmission cycles, or an origin in North America, prior to dispersal back into South American domestic cycles. To provide further insight we undertook high resolution nuclear and mitochondrial genotyping of multiple Central American strains (from areas of México and Guatemala) and included them in an analysis with other published data. FINDINGS: Mitochondrial sequence and nuclear microsatellite data revealed a cline in genetic diversity across isolates grouped into three populations: South America, North/Central America and TcI(DOM). As such, greatest diversity was observed in South America (A(r) = 4.851, π = 0.00712) and lowest in TcI(DOM) (Ar = 1.813, π = 0.00071). Nuclear genetic clustering (genetic distance based) analyses suggest that TcI(DOM) is nested within the North/Central American clade. CONCLUSIONS: Declining genetic diversity across the populations, and corresponding hierarchical clustering suggest that emergence of this important human genotype most likely occurred in North/Central America before moving southwards. These data are consistent with early patterns of human dispersal into South America.