The tissue specific tropism in Trypanosoma cruzi. Is it true?

Systematic microscopical observations on tissues from mice, inoculated with different Trypanosoma cruzi isolates, were carried out in order to assess whether the parasite expresses tissue-specific tropism, or if it can invade tissues pervasively within the mammal host. A total of ninety mice were included in the study. Sixty, subcutaneously-inoculated with 15 × 104T. cruzi-blood trypomastigotes were dissected and examined daily for detecting and counting parasites during 12 days of acute infection. Additionally, two long-term experiments using mice inoculated with 5 × 103 metacyclic-forms were performed. A group of 10 mice inoculated intraperitoneally and another group of 20 mice inoculated intradermally. Results demonstrated that T. cruzi does not exhibit a tissue-specific tropism, revealing characteristics of a paninfective species able to invade tissues of ectodermal, mesodermal, and endodermal embryonic origin, irrespective of the parasite's lineage, infective form, route of entry, or size of the inoculum causing the host's infection. Details on T. cruzi-tissue invasion, tissue-parasite load during the course time, and the hypothetical potential pseudocyst/amastigote whole-body burden in the murine model is analyzed. The importance of the findings and its interpretation related to human Chagas disease and the tissue-parasite persistence is also discussed.

Localization and developmental regulation of a dispersed gene family 1 protein in Trypanosoma cruzi.

The dispersed gene family 1 (DGF-1) is the fifth largest gene family in the Trypanosoma cruzi genome, with over 500 members (11). Many of the predicted DGF-1 protein products have several transmembrane domains and N-glycosylation and phosphorylation sites and were thought to localize in the plasma membrane. Here, we report that affinity-purified antibodies against a region of one of these proteins (DGF-1.2) localized it intracellularly in different stages of the parasite. DGF-1.2 is more abundant in the amastigote stage than in trypomastigotes and epimastigotes, as detected by immunofluorescence and Western blot analyses. The protein changed localization during intracellular or extracellular differentiation from the trypomastigote to the amastigote stage, where it finally localized to small bodies in close contact with the inner side of the amastigote plasma membrane. DGF-1.2 did not colocalize with markers of other subcellular organelles, such as acidocalcisomes, glycosomes, reservosomes, lipid droplets, or endocytic vesicles. During extracellular differentiation, the protein was detected in the culture medium from 0 to 22 h, peaking at 14 h. The presence of DGF-1.2 in the differentiation culture medium was confirmed by mass spectrometry analysis. Finally, when epimastigotes were subjected to starvation, there was a decrease in the labeling of the cells and, in Western blots, the appearance of bands of lower molecular mass, suggesting its cleavage. These results represent the first report of direct immunodetection and developmental expression and secretion of a DGF-1 protein.

Update on Chagas disease in Venezuela during the period 2003-2018. A review.

The present article reviews the status of Chagas disease in Venezuela during the period 2003-2018, based on the detection of Trypanosoma cruzi-infection in 3,343 blood samples of individuals from rural localities and 182 patients referred from health centers to confirm presumptive clinical diagnostic. The study involved samples from 81 rural localities of 17 states located at different regions and ecological life zones of the country. Analysis by parasitological (fresh microscopic observation, hemoculture and Giemsa stained blood smears), serological (DAT, IFAT-polyvalent, IgM, IgG tests) and molecular (PCR) tests, revealed 10.7% seroprevalence and 42.8% T. cruzi-infection, in individuals from rural localities and referred patients, respectively. In both groups T. cruzi-infection was detected at any age, revealing active transmission in children under 10-years-old. Clinical profile detected in referred patients, showed significantly major number of symptoms in orally infected patients than in infected by vectorial route (P<0.01). Genetic characterization of T. cruzi isolates obtained from orally and vectorial transmitted acute Chagas disease in western Venezuela, revealed the circulation of DTUI and DTUIII in the former, and DTUI, DTUII and DTUIII in patients infected by vectorial route. DTUI predominated in both cases, and haplotype Ib was the most frequently found in this genotype. Statistical analysis of clinical profile - T. cruzi DTUs - transmission route relationships did not show association among these variables and, consequently, chagasic patient's clinical condition did not depend of T. cruzi genotype or its route of transmission. In addition, differences in clinical severity may be associated with host susceptibility and/or parasite load received by the human receptor in spite of the T. cruzi genotype itself. The epidemiological implications of the present findings are discussed, and the need for developing efficient tools as well as implementation of urgent and radical changes in the public health policy to control Chagas disease transmission in the Venezuelan territory are suggested.

Isolation, purification, characterization and antigenic evaluation of GPI-anchored membrane proteins from Leishmania (Viannia) braziliensis.

GPI-anchored proteins from the plasma membrane of Leishmania (Viannia) braziliensis promastigotes were isolated, characterized and their migration pattern compared with those from other Leishmania species. In all cases the SDS-PAGE migration patterns were obtained under reducing and non-reducing conditions, using DL-dithiothreitol (DTT) as a reducer agent. Our results reveal that under reducing conditions the SDS-PAGE migration pattern is modified as a consequence of the disruption of disulphur-bonds and protein transformation. This is demonstrated when in non-reducing conditions the L. (V.) braziliensis-GPI-anchored proteins pattern showed a group of bands over the 100kDa, and two more bands of 52kDa and 50kDa in four different isolates, whereas under reducing conditions the major GPI-anchored protein fractions were detected as bands of 63kDa, 50kDa and an increase of peptides between 34kDa and 22kDa. Similar modifications were detected in the SDS-PAGE migration patterns of GPI-anchored protein fractions from L. (Leishmania) donovani, L. (L.) mexicana and L. (L.) amazonensis run under the same reducing conditions. Antigenic evaluation carried out by Western blot revealed the presence of two very specific L. (V.) braziliensis-GPI-anchored protein bands of 50kDa and 28kDa. These bands were specifically recognized by anti-L. (V.) braziliensis-GPI-anchored protein serum from experimentally immunized animals. These two peptides were not detected when GPI-anchored protein fractions from L. (L.) donovani, L. (L.) mexicana and L. (L.) amazonensis, were challenged with the same anti-serum. The present results lead us to suggest the use of these two peptides as biochemical markers to identify and differentiate leishmaniasis caused by L. (V.) braziliensis. The lack of immunogenicity observed here with the peptide gp63, a very common protein detected in Leishmania species, is considered.

Expression of GP82 and GP90 surface glycoprotein genes of Trypanosoma cruzi during in vivo metacyclogenesis in the insect vector Rhodnius prolixus.

Trypanosoma cruzi, the parasite causing Chagas' disease, relies on triatomines for its transmission. T. cruzi metacyclic trypomastigotes express GP82 and GP90, which are developmentally regulated surface proteins that have been implicated in host cell invasion. We used quantitative RT-PCR to quantify GP90 and GP82 mRNA levels expressed by T. cruzi in the digestive tract of experimentally infected Rhodnius prolixus at different times post infection. Translation of these transcripts was assessed by immunofluorescence using specific monoclonal antibodies against GP90 and GP82. We found that although GP82 and GP90 proteins were not detected in epimastigote cells by immunofluorescence, transcripts were present at lower levels. Increased levels of GP90 and GP82 transcripts and the appearance of these proteins on the parasite surface were accompanied by morphological differentiation from epimastigotes into metacyclic forms. Our data suggest that during in vivo metacyclogenesis there is a coordinated mechanism that links stabilization of GP90 and GP82 mRNAs with their translation.

Successful treatment against American cutaneous leishmaniasis by intralesional infiltration of a generic antimonial compound-lidocaine combination. A follow up study.

One hundred and twenty-two lesions caused by Leishmania braziliensis in 92 patients were treated using weekly intralesional (IL) infiltrations of a generic pentavalent antimonial compound, combined with local anesthetics. The topical therapy produced satisfactory healing in all the included patients, bearing from single-small ulcers to multiple or big lesions, after receiving an average 6 ±â€¯3 IL infiltrations (90 mgSb5+each). The rapid effect of this compound was demonstrated by the observed decrease of the Leishmania-amastigote population following microscopical grading in complicated ulcers after receiving two infiltrations. Neither discomfort nor side effects after infiltrations were recorded from the treated patients at any time. In addition, no signs of cutaneous relapse or mucosal lesion were detected during follow up after a decade clinical healing in 22% of the treated patients. Investment to produce the generic antimonial-IL treatment resulted significantly lower than the standard antimonial systemic therapy, and its cost/risk is discussed. The minimal dose of Sb5+ causing non-side effects or patient discomfort, the low production cost and the here demonstrated successful results, lead us to propose this generic antimonial compound as an alternative therapy for leishmanial-control in areas where American cutaneous leishmaniasis is endemic.

Genetic Diversity and Phylogenetic Relationships of Coevolving Symbiont-Harboring Insect Trypanosomatids, and Their Neotropical Dispersal by Invader African Blowflies (Calliphoridae).

This study is about the inter- and intra-specific genetic diversity of trypanosomatids of the genus Angomonas, and their association with Calliphoridae (blowflies) in Neotropical and Afrotropical regions. Microscopic examination of 3,900 flies of various families, mostly Calliphoridae, revealed that 31% of them harbored trypanosomatids. Small subunit rRNA (SSU rRNA) barcoding showed that Angomonas predominated (46%) over the other common trypanosomatids of blowflies of genera Herpetomonas and Wallacemonas. Among Angomonas spp., A. deanei was much more common than the two-other species, A. desouzai and A. ambiguus. Phylogenetic analyses based on SSU rRNA, glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) and internal transcribed spacer rDNA (ITS rDNA) sequences revealed a marked genetic diversity within A. deanei, which comprised four infraspecific genotypes (Dea1-Dea4), and four corresponding symbiont genotypes (Kcr1-Kcr4). Host and symbiont phylogenies were highly congruent corroborating their co-divergence, consistent with host-symbiont interdependent metabolism and symbiont reduced genomes shaped by a long coevolutionary history. We compared the diversity of Angomonas/symbionts from three genera of blowflies, Lucilia, Chrysomya and Cochliomyia. A. deanei, A. desouzai, and A. ambiguus were found in the three genera of blowflies in South America. In Africa, A. deanei and A. ambiguus were identified in Chrysomya. The absence of A. desouzai in Africa and its presence in Neotropical Cochliomyia and Lucilia suggests parasite spillback of A. desouzai into Chrysomya, which was most likely introduced four decades ago from Africa into the Neotropic. The absence of correlation between parasite diversity and geographic and genetic distances, with identical genotypes of A. deanei found in the Neotropic and Afrotropic, is consistent with disjunct distribution due to the recent human-mediated transoceanic dispersal of Angomonas by Chrysomya. This study provides the most comprehensive data gathered so far on the genetic repertoires of a genus of trypanosomatids found in flies from a wide geographical range.

Isolation, purification and characterization of GPI-anchored membrane proteins from Trypanosoma rangeli and Trypanosoma cruzi.

GPI-anchored proteins from plasma membrane of Trypanosoma rangeli and Trypanosoma cruzi epimastigotes were isolated and characterized using the partition Triton X-114 method. The detection by Western blot of specific proteins of 90, 85 and 56 kDa molecular mass in T. rangeli compared to those of 30, 70 and 100 kDa detected in T. cruzi demonstrates specific discrimination between these two species of Trypanosoma. The potential diagnostic value of the here reported proteins to differentiate mixed infections by T. cruzi and T. rangeli is evaluated and its potential for epidemiological studies of Chagas disease in endemic areas is also discussed.

Infected dogs as a risk factor in the transmission of human Trypanosoma cruzi infection in western Venezuela.

A total of 565 mongrel dogs from rural localities of Venezuela were examined by serological (DAT, IFAT and ELISA) and parasitological tests to address the status of Trypanosoma cruzi infection and to evaluate their role in the transmission of the infection to human population. The overall percentage of sero-positive infected dogs shown to be 67.6% (382/565):253 (61.7%) from 47 villages belonging to 8 states located at 4 different geographical regions of western Venezuela and 129 (33.5%) dogs from 48 households located in areas where Chagas disease is endemic. From 101 sampled dogs living in close proximity to 30 acute chagasic patients, 84% expressed specific anti-T. cruzi antibodies (Ab) with 12 of them (14%) showing blood circulating parasites (BCP). In these houses a high proportion of sero-positive people (20%) and frequent indoor infestation by triatomine-bugs (70%) was also recorded. The analysis revealed that from the 47 rural villages sampled during the study, 91.5% had the presence of T. cruzi sero-positive dogs, ranging from 62% positive localities at the states of Falcon and Cojedes to 100% in the other six studied Venezuelan states. This demonstrates that T. cruzi-infected dogs are found throughout all the geographical regions of western Venezuela irrespective of their ecological differences. Molecular typing of T. cruzi isolates from infected dogs using ribosomal and mini-exon gene markers, revealed the presence of both T. cruzi I and T. cruzi II lineages. The coincidence in the circulation of T. cruzi II in dog and human populations at the same locality and at the same time is reported and its significance is discussed. The combined serological, parasitological, epidemiological and molecular data is gathered here to call the attention on the presence of infected dogs as a risk factor in the maintenance of T. cruzi as a source for infection to humans.

Nestedness patterns of sand fly (Diptera: Psychodidae) species in a neotropical semi-arid environment.

A common pattern in neotropical Leishmania spp. transmission is the co-occurrence of several sand fly (SF) species at endemic foci. We collected 13 SF spp. by direct aspiration in natural resting places (NRP) and 10 SF spp. with Shannon traps (ST), totaling 15 spp. with both methods, at 6 locations within a semi-arid region with endemic visceral leishmaniasis transmission in Falcón State, Northwestern Venezuela. We used null model testing of species co-occurrence and nestedness metrics estimated with our field data to ask whether SF species composition was segregated/aggregated, and if aggregated whether there was nestedness, i.e., whether species composition across sampling locations could be described by ordered subsets of species from the most species rich location in a landscape. Results showed that SF species were aggregated (P<0.05), i.e., most species were present in species rich locations. Similarly, SF species were significantly nested (P<0.05). Differences in pairwise Sørensen and Simpson indices, estimated with the ST data and the combined ST and NRP data, were positively associated with the distance between sampling locations, suggesting that species nestedness might be partially shaped by dispersal limitation. Our data showed that three species of medical importance were common across the sampling locations: Lutzomyia gomezi, Lutzomyia panamensis and Lutzomyia evansi, suporting that vector species do not turnover in the studied setting.

Expression of fluorescent genes in Trypanosoma cruzi and Trypanosoma rangeli (Kinetoplastida: Trypanosomatidae): its application to parasite-vector biology.

Two Trypanosoma cruzi-derived cloning vectors, pTREX-n and pBs:CalB1/CUB01, were used to drive the expression of green fluorescent protein (GFP) and DsRed in Trypanosoma rangeli Tejera, 1920, and Trypanosoma cruzi Chagas, 1909, isolates, respectively. Regardless of the species, group, or strain, parasites harboring the transfected constructs as either episomes or stable chromosomal integrations showed high-level expression of fluorescent proteins. Tagged flagellates of both species were used to experimentally infect Rhodnius prolixus Stal, 1953. In infected bugs, single or mixed infections of T. cruzi and T. rangeli displayed the typical cycle of each species, with no apparent interspecies interactions. In addition, infection of kidney monkey cells (LLC-MK2) with GFP-T. cruzi showed that the parasite retained its fluorescent tag while carrying out its life cycle within cultured cells. The use of GFP-tagged parasites as a tool for biological studies in experimental hosts is discussed, as is the application of this method for copopulation studies of same-host parasites.

Chagas' disease diagnosis: a multicentric evaluation of Chagas Stat-Pak, a rapid immunochromatographic assay with recombinant proteins of Trypanosoma cruzi.

A rapid serologic test for diagnosis of T. cruzi infection (Chagas Stat Pak) was developed using recombinant proteins in an immunochromatographic assay. This cassette format test was evaluated first in blind with a panel of 393 coded serum samples. The Chagas Stat-Pak identified 197 infected (98.5% sensitivity) and 183 non-infected individuals (94.8% specificity). A second evaluation was performed with 352 sera from four Latin America countries tested independently in each country, showing a sensitivity of 100% and specificity of 98.6%. A third set of tests comparing sera with plasma and eluates from filter paper as well as serum preserved in 50% glycerol did show identical results as those obtained with serum. This rapid test (15 min) uses one device per sample, does not require refrigeration nor a laboratory structure or specialized skills to be performed, accepts different types of samples and may be stored for long periods of time for result checking and documentation. These attributes together with the high sensitivity and specificity demonstrated herein, make this test a suitable tool for field studies, small laboratories and emergencies at blood banks in the countryside of endemic areas.

Species co-occurrence and feeding behavior in sand fly transmission of American cutaneous leishmaniasis in western Venezuela.

The structure of the Phlebotomine sand fly community from the Venezuelan Andes was studied using null-model tests. The analyses, at the living zones and altitudes scales, revealed C-scores larger than those expected by random, independently of the collection technique (P < 0.05). These results imply that sand fly species are non-aggregated at both scales. Random results for the variance of C-score and for the favored states hypothesis suggest that sand fly species belong to an unique guild. The latter is reinforced by the fact that anthropophilic and zoophilic species use in the same way a common resource (blood). Finally, we suggest additional approaches to study the role of the sand fly community structure on the genesis and dynamics of transmission of American cutaneous leishmaniasis.

Aneurisma cardíaco apical en paciente chagásico agudo de avanzada edad: Reporte de un caso / Apical cardiac aneurism in acute chagasic aged patient: A case report

Se presenta el caso de un paciente de la tercera edad mostrando cuadro agudo sintomático con complicaciones cardiacas evidenciadas por detección de fibrilación auricular, miopericarditis, derrame pericárdico moderado, sin signos de taponamiento cardíaco, fracción de eyección del ventrículo izquierdo (FEVI) < 30% y aneurisma, detectados mediante estudios electro y eco cardiográficos, respectivamente. El despistaje parasitológico reveló la presencia de Trypanosoma cruzi en muestra de sangre circulante y líquido pericárdico, con hemocultivo positivo y detección de ADN específico del parásito por ensayos de PCR. Asimismo, la presencia de altos niveles de anticuerpos circulantes anti-T. cruzi detectados con dos pruebas serológicas (TAD, IFI) y la observación de altos niveles IgM, corroboran el diagnóstico de un cuadro de enfermedad de Chagas en fase aguda de la infección. Además, la procedencia del paciente de una localidad andina del occidente de Venezuela, donde la enfermedad de Chagas es endémica, unido al hallazgo de ejemplares adultos de triatominos en la vivienda del paciente confirman el diagnóstico. Se discute la significación del presente hallazgo y se detallan las observaciones durante la re-evaluación en el seguimiento post tratamiento.

A Clinical case from an aged patient with evidence of suffering heart failure showing arrhythmia, atrial fibrillation and pericarditis, pericardial effusion and left ventricle aneurism detected by electrocardiogram and echocardiogram respectively, is reported. Parasitological examination revealed presence of Trypanosoma cruzi in blood and pericardial fluid samples. In addition, hemoculture was positive and PCR assay revealed specific T. cruzi DNA. Serological techniques (DAT, IFAT) showed anti-T.cruzi circulating antibodies, including high level IgM. The sero-parasitological and molecular (PCR) findings confirmed the presumptive clinical diagnosis for Chagas disease acute infection. The significance of the present findings is discussed and clinical details observed during re-evaluation post-treatment, are included.

Trypanosoma cruzi persistence at oral inflammatory foci in chronic chagasic patients.

The persistence of Trypanosoma cruzi in seropositive individuals, previously diagnosed as chronic chagasic patients (CCP), was detected for the first time in biopsies taken from gingival inflammatory foci processed by polymerase chain reaction (PCR). Seven out of 31 (22.5%) gum samples from selected unquestionably CCP showing different degrees of gingival inflammation revealed T. cruzi-DNA using 3 specific PCR assays. All the included CCP had been diagnosed in previous studies carried out over the last 19 years. Samples of inflamed gums were recently taken from the indicated patients at: an outpatient hospital cardiac unit; a village where Chagas disease is endemic; and a specialized diagnostic research center, showing molecular evidence of parasite persistence in 17.6%, 42.8% and 14.3% of them, respectively. The relatively frequent parasite persistence, demonstrated here in oral inflammatory processes of treated and/or untreated patients bearing long term T. cruzi-infection, suggests the establishment of secondary small foci for the maintenance of hidden or inapparent chagasic infection. The easy and low-risk, non-invasive method to get the sample may add the use of gingival biopsy as a potential alternative diagnostic tool to confirm T. cruzi-infection in CCP. The significance of T. cruzi persistence as a primary cause of chronic Chagas disease and the proposal of this mechanism to explain the pathogenesis in CCP are considered.

International study to evaluate PCR methods for detection of Trypanosoma cruzi DNA in blood samples from Chagas disease patients.

BACKGROUND: A century after its discovery, Chagas disease still represents a major neglected tropical threat. Accurate diagnostics tools as well as surrogate markers of parasitological response to treatment are research priorities in the field. The purpose of this study was to evaluate the performance of PCR methods in detection of Trypanosoma cruzi DNA by an external quality evaluation. METHODOLOGY/FINDINGS: An international collaborative study was launched by expert PCR laboratories from 16 countries. Currently used strategies were challenged against serial dilutions of purified DNA from stocks representing T. cruzi discrete typing units (DTU) I, IV and VI (set A), human blood spiked with parasite cells (set B) and Guanidine Hidrochloride-EDTA blood samples from 32 seropositive and 10 seronegative patients from Southern Cone countries (set C). Forty eight PCR tests were reported for set A and 44 for sets B and C; 28 targeted minicircle DNA (kDNA), 13 satellite DNA (Sat-DNA) and the remainder low copy number sequences. In set A, commercial master mixes and Sat-DNA Real Time PCR showed better specificity, but kDNA-PCR was more sensitive to detect DTU I DNA. In set B, commercial DNA extraction kits presented better specificity than solvent extraction protocols. Sat-DNA PCR tests had higher specificity, with sensitivities of 0.05-0.5 parasites/mL whereas specific kDNA tests detected 5.10(-3) par/mL. Sixteen specific and coherent methods had a Good Performance in both sets A and B (10 fg/µl of DNA from all stocks, 5 par/mL spiked blood). The median values of sensitivities, specificities and accuracies obtained in testing the Set C samples with the 16 tests determined to be good performing by analyzing Sets A and B samples varied considerably. Out of them, four methods depicted the best performing parameters in all three sets of samples, detecting at least 10 fg/µl for each DNA stock, 0.5 par/mL and a sensitivity between 83.3-94.4%, specificity of 85-95%, accuracy of 86.8-89.5% and kappa index of 0.7-0.8 compared to consensus PCR reports of the 16 good performing tests and 63-69%, 100%, 71.4-76.2% and 0.4-0.5, respectively compared to serodiagnosis. Method LbD2 used solvent extraction followed by Sybr-Green based Real time PCR targeted to Sat-DNA; method LbD3 used solvent DNA extraction followed by conventional PCR targeted to Sat-DNA. The third method (LbF1) used glass fiber column based DNA extraction followed by TaqMan Real Time PCR targeted to Sat-DNA (cruzi 1/cruzi 2 and cruzi 3 TaqMan probe) and the fourth method (LbQ) used solvent DNA extraction followed by conventional hot-start PCR targeted to kDNA (primer pairs 121/122). These four methods were further evaluated at the coordinating laboratory in a subset of human blood samples, confirming the performance obtained by the participating laboratories. CONCLUSION/SIGNIFICANCE: This study represents a first crucial step towards international validation of PCR procedures for detection of T. cruzi in human blood samples.

Trypanosoma cruzi congenital transmission in wild bats.

Trypanosoma cruzi congenital transmission in wild bats (Molossus molossus), associated with infected Rhodnius prolixus in a natural habitat from a rural locality in western Venezuela, is reported. T. cruzi blood circulating trypomastigotes in a pregnant bat were detected by parasitological methods. Polymerase chain reaction (PCR) assays carried out in samples from the heart and the fetus of the same infected female, revealed the presence of T. cruzi-specific DNA in both of the tissues, demonstrating transmission of the infection from the mother to the offspring. Eighty percent of the captured bats and 100% of the examined fetuses from pregnant specimens were shown to be infected by T. cruzi, indicating that M. molossus is a very susceptible species for this parasite, and that T. cruzi congenital transmission is a common phenomenon in nature. To our knowledge, this seems to be the first report on congenital T. cruzi transmission in wild bats in Venezuela. The circulation of T. cruzi lineage I in the study area was demonstrated by typing the isolates from bats and triatomine bugs captured in the same habitat. The potential epidemiological implication of these findings in areas where Chagas disease is endemic is discussed.

Brote de enfermedad de Chagas agudo de posible transmisión oral en Mérida, Venezuela / Acute Chagas disease outbreak of possible oral transmission in Merida, Venezuela

Se registra un brote de enfermedad de chagas agudo, en una localidad rural de Mérida-Venezuela, asociado con transmisión oral por ingesta contaminada con trypanosoma cruzi dada la masiva y simultanea infección detectada en 5 miembros de una familia. La masiva transmisión de T. cruzi generó cuadros clínicos severos causando miocarditis aguda en 2 pacientes (40%) incluyendo un caso fatal. La severidad clínica en todos los pacientes involucrados mostró correspondencia con los hallazgos parasitológicos, serológicos y moleculares (PCR) con los cuales se evidenció presencia de tripomastigotes sanguícolas de T. cruzi, anticuerpos anti-T. cruzi con niveles variables de IgM e IgG específicas y ADN de T. cruzi, respectivamente. Asimismo, el perfil clínico reveló 17 signos o síntomas con un promedio por paciente de 12±3 (rango=9-16) con simultaneidad en 8 de los síntomas más frecuentemente detectados. Resalta en la sintomatología la presencia de edema facial interno con manifiesta tumefacción y parestesia lingual en ausencia del cuadro típico de edema bipalpebral (signo de Romaña) y/o chagoma de inoculación comúnmente registrados en la infección chagásica por vía vectorial. Se argumenta la posibilidad de la transmisión oral y se discute la potencial importancia epidemiológica del presente hallazgo.

An acute Chagas disease outbreak associated with oral transmission, detected in a rural village of Merida- Venezuela, is reported. The massive transmission due to ingestion of food contaminated with Trypanosoma cruzi generated, in 5 members of the same family, severe clinical features causing acute myocarditis in two of them (40%) including a fatal case. Parasitological, serological and molecular (PCR) examination of samples from the 5 patients involved in the outbreak, revealed T.cruzi blood circulating tripomastigotes, anti-T. cruzi specific antibodies (IgM; IgG) and the presence of T. cruzi respectively. The recorded clinical pattern detected a total of 17 signs or symptoms with an average ± SD 12±3 per patients (range = 9-16) showing simultaneity in 8 symptoms and a 20% mortality. A remarkable characteristic detected during the study was the presence of internal facial swollen with paresthesia in tongue in absence of the typical Romaña's sign or chagoma commonly found in Chagas disease-infection caused by vector transmission. The possible oral transmission and the potential of the findings from the epidemiological viewpoint are discussed.

Detección de Leishmania braziliensis en lesión mucosa con 16 años de evolución: Registro de un caso / Detection of Leishmania braziliensis in a mucosal lesion with 16 years of evolution: A case report

Se registra, en un paciente masculino de 48 años, la detección de Leishmania (Viannia) braziliensis en muestra de lesión mucosa crónica con 16 años de evolución clínica. El caso presentado cursa con perforación del tabique nasal no evidenciándose lesión cutánea primaria sugestiva de leishmaniasis. Por su ocupación el paciente ha frecuentado, por largos períodos, bosques en áreas endémicas para leishmaniasis en el occidente de Venezuela. Continuas evaluaciones clínicas, inmunológicas e histopatológicas realizadas durante varios años fallaron en establecer un diagnóstico certero incrementando la severidad del caso. Exámenes recientes realizados en nuestro laboratorio revelan la presencia de amastigotes en muestras de la lesión nasal activa en extendidos coloreados con tinción de Giemsa. La identificación del parásito como L. braziliensis y la verificación de la infección por este parásito en el paciente, fue lograda por ensayos de PCR y Western Blot, respectivamente. Se concluye que el caso presentado sufre una leishmaniasis mucocutánea de vieja data con una baja respuesta inmunológica, a juzgar por la frecuente negatividad en pruebas de IDR y/o la detección de anticuerpos circulantes anti-Leishmania. Se discute sobre la imprecisión diagnóstica en el caso presentado y se advierte sobre el riesgo epidemiológico potencial de casos similares.

The detection of Leishmania (Viannia) braziliensis from a chronic mucosal lesion with 16 years of clinical evolution in a 48 years old male patient is reported. The patient showed destruction of the nasal septal cartilage with no evidence of primary leishmanial lesion. Due to his professional work he frequently visited areas of western Venezuela where leishmaniasis is endemic. Frequent clinical, immunologic and histopathologic evaluations carried out during several years failed to establish a right diagnosis, increasing the severity of the mucosal lesion. The finding of a sparse number of amastigotes in a sample from the mucosal lesion stained by Giemsa stain, suggested a mucosal infection by Leishmania. The identification of the parasite as L. braziliensis and the verification of the infection by this parasite in the reported case were carried out using a PCR assay and a Western Blot test, respectively. It is concluded that the patient was suffering a long-lasting, reluctant to heal and severe lesion with a low immunological response due to infection by L. braziliensis causing mucocutaneous leishmaniasis (MCL). The fail in the diagnosis of this particular case of MCL and the potential epidemiological risk in similar cases are discussed.