Identification of a Western blot pattern for the specific diagnosis of Trypanosoma cruzi infection in human sera

Characterization of Novel Trypanosoma cruzi-Specific Antigen with Potential Use in the Diagnosis of Chagas Disease

Chagas disease is caused by the parasite Trypanosoma cruzi. In humans, it evolves into a chronic disease, eventually resulting in cardiac, digestive, and/or neurological disorders. In the present study, we characterized a novel T. cruzi antigen named Tc323 (TcCLB.504087.20), recognized by a single-chain monoclonal antibody (scFv 6B6) isolated from the B cells of patients with cardiomyopathy related to chronic Chagas disease. Tc323, a ~323 kDa protein, is an uncharacterized protein showing putative quinoprotein alcohol dehydrogenase-like domains. A computational molecular docking study revealed that the scFv 6B6 binds to an internal domain of Tc323. Immunofluorescence microscopy and Western Blot showed that Tc323 is expressed in the main developmental forms of T. cruzi, localized intracellularly and exhibiting a membrane-associated pattern. According to phylogenetic analysis, Tc323 is highly conserved throughout evolution in all the lineages of T. cruzi so far identified, but it is absent in Leishmania spp. and Trypanosoma brucei. Most interestingly, only plasma samples from patients infected with T. cruzi and those with mixed infection with Leishmania spp. reacted against Tc323. Collectively, our findings demonstrate that Tc323 is a promising candidate for the differential serodiagnosis of chronic Chagas disease in areas where T. cruzi and Leishmania spp. infections coexist.

Characterization of Latin American migrants at risk for Trypanosoma cruzi infection in a non-endemic setting. Insights into initial evaluation of cardiac and digestive involvement

BACKGROUND

Trypanosoma cruzi causes Chagas disease (CD), a potentially fatal disease characterized by cardiac disorders and digestive, neurological or mixed alterations. T. cruzi is transmitted to humans by the bite of triatomine vectors; both the parasite and disease are endemic in Latin America and the United States. In the last decades, population migration has changed the classic epidemiology of T. cruzi, contributing to its global spread to traditionally non-endemic countries. Screening is recommended for Latin American populations residing in non-endemic countries.

METHODS

The present study analyzes the epidemiological characteristics of 2,820 Latin American individuals who attended the International Health Service (IHS) of the Hospital Clinic de Barcelona between 2002 and 2019. The initial assessment of organ damage among positive cases of T. cruzi infection was analyzed, including the results of electrocardiogram (ECG), echocardiogram, barium enema and esophagogram.

RESULTS

Among all the screened individuals attending the clinic, 2,441 (86.6%) were born in Bolivia and 1,993 (70.7%) were female. Of individuals, 1,517 (81.5%) reported previous exposure to the vector, which is a strong risk factor associated with T. cruzi infection; 1,382 individuals were positive for T. cruzi infection. The first evaluation of individuals with confirmed T. cruzi infection, showed 148 (17.1%) individuals with Chagasic cardiomyopathy, the main diagnostic method being an ECG and the right bundle branch block (RBBB) for the most frequent disorder; 16 (10.8%) individuals had a normal ECG and were diagnosed of Chagasic cardiomyopathy by echocardiogram.

CONCLUSIONS

We still observe many Latin American individuals who were at risk of T. cruzi infection in highly endemic areas in their countries of origin, and who have not been previously tested for T. cruzi infection. In fact, even in Spain, a country with one of the highest proportion of diagnosis of Latin American populations, T. cruzi infection remains underdiagnosed. The screening of Latin American populations presenting with a similar profile as reported here should be promoted. ECG is considered necessary to assess Chagasic cardiomyopathy in positive individuals, but echocardiograms should also be considered as a diagnostic approach given that it can detect cardiac abnormalities when the ECG is normal.

Western blot using Trypanosoma cruzi chimeric recombinant proteins for the serodiagnosis of chronic Chagas disease: A proof-of-concept study

BACKGROUND

Chagas disease (CD) is caused by Trypanosoma cruzi. The chronic phase of CD is characterized by the presence of IgG anti-T. cruzi antibodies; and diagnosis is performed by serological methods. Because there is no reliable test that can be used as a reference test, WHO recommends the parallel use of two different tests for CD serodiagnosis. If results are inconclusive, samples should be subjected to a confirmatory test, e.g., Western blot (WB) or PCR. PCR offers low sensitivity in the chronic phase, whereas few confirmatory tests based on the WB method are commercially available worldwide. Therefore, new diagnostic tools should be evaluated to fill the gap in CD confirmatory tests. In recent years, four chimeric recombinant antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4) have been evaluated in phase I, II and III studies using ELISA, liquid microarray and immunochromatography with 95-100% accuracy. Given the high diagnostic performance of these antigens, the present study investigated the ability of these molecules to diagnose chronic CD using a WB testing platform.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, we analyzed the diagnostic potential of four chimeric antigens using 40 T. cruzi-positive, 24-negative, and three additional positive samples for visceral leishmaniasis (i.e., potentially cross-reactive) using WB as the diagnostic platform. Checkerboard titration with different dilutions of antigens, conjugated antigens, and serum samples was performed to standardize all assays. All IBMP antigens achieved 100% sensitivity, specificity, and accuracy, with the exception of IBMP-8.3, which had 100% specificity despite lack of significance, but lower sensitivity (95%) and accuracy (96.9%). No cross-reactivity was observed in samples positive for leishmaniasis.

CONCLUSIONS/SIGNIFICANCE

The present phase I (proof-of-concept) study demonstrated the high diagnostic potential of these four IBMP antigens to discriminate between T. cruzi-positive and -negative samples, making them candidates for phase II and confirmatory testing with WB.

Critical analysis of Chagas disease treatment in different countries

As a result of globalization and constant migratory flows, Chagas disease is now present in almost all continents. The management and treatment of the disease is often influenced by the economic and social context of the societies that host patients. In this manuscript, we aim to provide a comparative review of approaches to patients with Chagas disease in the Americas and Europe.

Worldwide Control and Management of Chagas Disease in a New Era of Globalization: a Close Look at Congenital Trypanosoma cruzi Infection

Population movements have turned Chagas disease (CD) into a global public health problem. Despite the successful implementation of subregional initiatives to control vectorial and transfusional Trypanosoma cruzi transmission in Latin American settings where the disease is endemic, congenital CD (cCD) remains a significant challenge. In countries where the disease is not endemic, vertical transmission plays a key role in CD expansion and is the main focus of its control. Although several health organizations provide general protocols for cCD control, its management in each geopolitical region depends on local authorities, which has resulted in a multitude of approaches. The aims of this review are to (i) describe the current global situation in CD management, with emphasis on congenital infection, and (ii) summarize the spectrum of available strategies, both official and unofficial, for cCD prevention and control in countries of endemicity and nonendemicity. From an economic point of view, the early detection and treatment of cCD are cost-effective. However, in countries where the disease is not endemic, national health policies for cCD control are nonexistent, and official regional protocols are scarce and restricted to Europe. Countries of endemicity have more protocols in place, but the implementation of diagnostic methods is hampered by economic constraints. Moreover, most protocols in both countries where the disease is endemic and those where it is not endemic have yet to incorporate recently developed technologies. The wide methodological diversity in cCD diagnostic algorithms reflects the lack of a consensus. This review may represent a first step toward the development of a common strategy, which will require the collaboration of health organizations, governments, and experts in the field.

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

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

Update on the major imported protozoan infections in travelers and migrants

Globalization has contributed to the emergence of specific parasitic diseases in novel geographical areas, and in these regions, these infections in travelers and immigrants may cause a considerable burden of disease. Timely diagnosis and treatment of protozoan infections to decrease mortality and prevent associated complications are essential. In this respect, the increased availability of specific DNA-detection procedures has improved the diagnosis of many imported parasitic infections. Travelers and immigrants with associated comorbidities or immunosuppression may pose a special challenge regarding management. An updated review of the main protozoan infections in mobile populations (malaria, Chagas disease, leishmaniasis, enteric protozoan infections) is provided, focusing on the changing epidemiology of these diseases, recent developments in diagnosis and management and the possibility of local transmission of imported infections.

Overcoming challenges in the diagnosis and treatment of parasitic infectious diseases in migrants

Introduction: Recent increases in population movements have created novel health challenges in many areas of the World, and health policies have been adapted accordingly in several countries. However, screening guidelines for infectious diseases are not standardized and generally do not include comprehensive screening for parasitic infections.Areas covered: Malaria, Chagas disease, leishmaniasis, amebiasis, filariases, strongyloidiasis, and schistosomiasis are reviewed, focusing on the challenges posed for their diagnosis and management in vulnerable populations such as migrants. The methodology included literature searches in public databases such as PubMed.gov and Google Scholar and search of the US National Library of Medicine online database of privately and publicly funded clinical studies (ClinicalTrials.gov) until November 2019.Expert opinion: Parasitic infections which may remain asymptomatic for prolonged periods, leading to chronic infection and complications, and/or may be transmitted in non-endemic areas are ideal candidates for screening. Proposed strategies to improve diagnosis in vulnerable groups such as migrants include facilitating access to healthcare in a multi-dimensional manner considering location, individual characteristics, and timing. Limitations and availability of specific diagnostic techniques should be addressed and focus on drug and vaccine development for these neglected infections should be prioritized through collaborative initiatives with public disclosure of results.

A retrospective study on the influence of siblings' relatedness in Bolivian patients with chronic Chagas disease

BACKGROUND

Chagas disease is a protozoan infection caused by Trypanosoma cruzi. The disease has a chronic course in which 20-30% of the patients would develop progressive damage to the cardiovascular system and the gastrointestinal tube. We are still unable to predict who will develop end-organ damage but there are some acquired and genetic risk factors already known.

RESULTS

We reviewed data from 833 patients with serologically confirmed Chagas disease in this retrospective study. Patients were classified as siblings or non-siblings (controls) and the results of pre-treatment blood PCR assay, end-organ damage (cardiac and/or gastrointestinal), and the presence of delayed type hypersensitivity (DTH) skin involvement in patients treated with benznidazole were analyzed. Siblings were grouped by family and we randomly generated groups of 2 or 3 persons with the remaining controls. We classified the results of each variable as concordant or discordant and compared the concordance in these results among the sibling groups with that among control groups. We identified 71 groups of siblings and randomly generated 299 groups of non-related patients. Pre-treatment blood PCR concordance was significantly higher (19%) among siblings compared to controls (P = 0.02), probably due to a higher frequency in pre-treatment positive results. No other statistically significant differences were found.

CONCLUSIONS

A significant difference was found in the concordance of pre-treatment blood PCR for T. cruzi among siblings compared to non-related controls.

First report of family clusters of Chagas disease seropositive blood donors in Mexico City and their epidemiological relevance

BACKGROUND

Chagas disease is an important health problem in Latin America. Relatives of T. cruzi seropositive donors could also test positive in serological assays. Therefore, the study of Chagas diseases in family clusters has become important to accurately evaluate the problem that this infectious disease represents.

OBJECTIVE

to investigate family cluster from blood donors, their serological, clinical and epidemiological status.

METHODS

53 family clusters consisting of index case and a variable number of relatives were studied. All the participants had ELISA and Western blot assays, as well as, clinical tests including an electrocardiogram and chest x ray.

RESULTS

We found that 24.52% of the family clusters had at least one T. cruzi seropositive family member, in addition to the blood donor. Importantly, 20.75% of the index cases and 5.0% of the relatives presented pathological manifestations associated to Chagas disease. Several epidemiological conditions are associated to being T. cruzi seropositive.

CONCLUSION

blood donor's family clusters have several seropositive to T. cruzi members. Mother-child pairs were also seropositive, suggesting vertical transmition. Pathological symptom associated to Chagas Diseases were present in index cases and family member. These results highlight the importance of studying family clusters to clarify the true magnitude of Chagas disease in Mexico.

The challenge of discordant serology in Chagas disease: The role of two confirmatory techniques in inconclusive cases

Serodiscordance in Chagas disease (CD) remains a challenge since individuals with inconclusive results are clinically complicated to manage. This work, conducted outside the endemic area, aims to compare two different confirmatory techniques for the diagnosis of CD in individuals without a definitive diagnosis, to analyze the performance of the screening techniques in this group of patients, and to describe the serological follow-up of these subjects over time. Sera from 48 individuals with repeatedly discordant results by one recombinant enzyme immunoassay (r-ELISA) and one native ELISA (n-ELISA), were included in the study. Confirmatory procedures were performed through TESA-blot, using trypomastigote antigens of Trypanosoma cruzi, and in-house WB (IH-WB) using a lysate from T. cruzi epimastigotes. Of the 48 sera, TESA-blot confirmed 22 (45.8%) cases and IH-WB 17 (35.4%). Both techniques showed a substantial agreement (k = 0.604). Confirmation defined as the positivity of one of the ELISA and at least one of the confirmatory tests was reached in 24/48 (50%) cases. We found a great dispersion of r-ELISA index values, especially among individuals with confirmatory negative results, ranging from 0.03-6.2. Additionally, n-ELISA yielded a better performance than r-ELISA in this cohort of patients, showing a significantly greater agreement with the confirmatory methods. Our results indicate that either confirmatory test could be an efficient tool to solve inconclusive cases regardless of which form of the parasite's life cycle they use. Also, most individuals remain with discordant serology throughout the short-term follow-up period time of study. Finally, we consider that it is necessary to establish a reference test feasible and commercialized in all areas to solve the problem of inconclusive results.

Immunodetection and molecular determination of visceral and cutaneous Leishmania infection using patients' urine

The diagnosis of leishmaniasis relies mainly on the use of invasive processes, to collect the biological material for detecting Leishmania parasites. Body fluids, which can be collected by non-invasive process, would greatly facilitate the leishmaniasis diagnosis. In the present study, we investigated the potency of urine immunoblotting to diagnose cutaneous and visceral leishmaniasis and we compared with routine molecular methods. A total of 80 samples, including 40 sera and their 40 corresponding urine samples were collected from 37 suspected patients with cutaneous and visceral leishmaniasis, and 3 healthy individuals (as control), in Ilam and Ardabil provinces of Iran. All sera and urine samples were analyzed, using immunoblotting. The confirmation of leishmaniasis infection was performed, using conventional and quantitative PCRs as well as by sequencing the amplicons. Among 37 suspected patients, 23 patients presented cutaneous lesions (CL) and 14 exhibited clinical symptoms reminiscent of visceral leishmaniasis (L. infantum). Among cutaneous patients, 15 were positive for zoonotic cutaneous leishmaniasis (L. major), and eight for anthroponotic cutaneous leishmaniasis (L. tropica). Molecular quantification of Leishmania parasites was performed on sera, urines and cutaneous biopsies of CL and VL patients, demonstrating that parasite load is lower in urines, compared to sera or biopsy. DNA can be detected in 20 out of 23 (86.9%) CL urine samples and in 13 out of 14 (92.8%) VL urine samples. Immunodetection analysis demonstrates that 22 out of 23 (95.6%) sera from CL patients and all patients suspected with VL are positive. For urine samples, 18 out of 23 (78.2%) urine of CL patients and 13 out of 14 (92.8%) urine of VL patients were positive, using Western blot. Therefore, immunodetection and molecular analysis using urine samples can be used as a diagnostic tool for surveying cutaneous and visceral leishmaniasis.

Chagas disease

Chagas disease is an anthropozoonosis from the American continent that has spread from its original boundaries through migration. It is caused by the protozoan Trypanosoma cruzi, which was identified in the first decade of the 20th century. Once acute infection resolves, patients can develop chronic disease, which in up to 30-40% of cases is characterised by cardiomyopathy, arrhythmias, megaviscera, and, more rarely, polyneuropathy and stroke. Even after more than a century, many challenges remain unresolved, since epidemiological control and diagnostic, therapeutic, and prognostic methods must be improved. In particular, the efficacy and tolerability profile of therapeutic agents is far from ideal. Furthermore, the population affected is older and more complex (eg, immunosuppressed patients and patients with cancer). Nevertheless, in recent years, our knowledge of Chagas disease has expanded, and the international networking needed to change the course of this deadly disease during the 21st century has begun.

Towards a New Strategy for Diagnosis of Congenital Trypanosoma cruzi Infection

The immigration of Latin American women of childbearing age has spread the congenital transmission of Chagas disease to areas of nonendemicity, and the disease is now a worldwide problem. Some European health authorities have implemented screening programs to prevent vertical transmission, but the lack of a uniform protocol calls for the urgent establishment of a new strategy common to all laboratories. Our aims were to (i) analyze the trend of passive IgG antibodies in the newborn by means of five serological tests for the diagnosis and follow-up of congenital Trypanosoma cruzi infection, (ii) assess the utility of these techniques for diagnosing a congenital transmission, and (iii) propose a strategy for a prompt, efficient, and cost-effective diagnosis of T. cruzi infection. In noninfected newborns, a continuous decreasing trend of passive IgG antibodies was observed, but none of the serological assays seroreverted in any the infants before 12 months. From 12 months onwards, serological tests achieved negative results in all the samples analyzed, with the exception of the highly sensitive chemiluminescent microparticle immunoassay (CMIA). In contrast, in congenitally infected infants, the antibody decline was detected only after treatment initiation. In order to improve the diagnosis of congenital T. cruzi infection, we propose a new strategy involving fewer tests that allows significant cost savings. The protocol could start 1 month after birth with a parasitological test and/or a PCR. If negative, a serological test would be carried out at 9 months, which if positive, would be followed by another at around 12 months for confirmation.

Serodiscordance in chronic Chagas disease diagnosis: a real problem in non-endemic countries

According to the WHO, chronic Chagas disease (CD) diagnosis is based on two serological techniques. To establish a definitive diagnosis, the results must be concordant. In cases of discordances, the WHO proposes repeating serology in a new sample, and if results remain inconclusive, a confirmatory test should be performed. This study, conducted at two Tropical Medicine Units in Europe over 4 years, aims to assess the diagnostic yield of TESA- (trypomastigote excreted-secreted antigens) blot as a confirmatory technique in patients with inconclusive and discordant results. Of 4939 individuals screened, 1124 (22.7%) obtained positive results and 165 (3.3%) discordant results. Serology was repeated in 88/165 sera and discrepancies were solved in 25/88 (28.4%) cases. Patients without a definitive diagnosis were classified in two different groups: Group 1, including patients with inconclusive results despite retesting (n = 63), and Group 2, including patients with discordant results not retested (n = 77). TESA-blot was performed for all of Group 1 and 39/77 of Group 2 and was positive for 33/63 (52.4%) and 21/39 (53.8%), respectively. Analysis of Group 1 results showed a moderate agreement between results of the ELISA based on native antigen and TESA-blot (κ 0.53). In contrast, a clear disagreement was observed between the ELISA based on recombinant antigens and TESA-blot (κ <0). A sizeable proportion of patients are suspected to have CD with inconclusive results or in whom re-testing is not feasible. TESA-blot was positive in half of these patients, highlighting the need for a confirmatory assay in European centres caring for exposed individuals.

Chagas Cardiomyopathy: Usefulness of EKG and Echocardiogram in a Non-Endemic Country

BACKGROUND

Chagas disease (CD) is a major cause of cardiomyopathy in Latin America, and migration movements have now spread the disease worldwide. However, data regarding Chagas cardiomyopathy (CC) and the usefulness of echocardiography in non endemic countries are still scarce.

METHODS AND RESULTS

We selected 485 patients in the chronic phase of CD from two Spanish settings. Data from physical examination, electrocardiogram (EKG), x-ray, and two dimensional transthoracic echocardiogram were recorded. Trypanosoma cruzi DNA was assessed by PCR in peripheral blood. Patients were stratified according to the Kuschnir classification and a combination of echocardiogram and electrocardiogram findings. Patients mainly came from Bolivia (459; 94.6%). One hundred and forty three patients (31.5%) had at least one electrocardiogram abnormality. Twenty seven patients (5.3%) had an abnormal echocardiography. Patients with abnormal echocardiography were older (47 (IQR 38-57) years vs 41 (IQR 38-57) years); p = 0.019) and there was a greater proportion of males (66.7% vs 29.7%); p<0.001). Among echocardiographic variables, diastolic dysfunction was associated with poor cardiac status. In the multivariate analysis, abnormal EKG and gender were associated with abnormal echocardiography. Echocardiography may be spared for males under 30 and females under 45 years old with normal EKG as the likelihood of having an abnormal echocardiography is minimal. Association between T. cruzi DNA in the peripheral blood and cardiac involvement was not observed.

CONCLUSION

CC rates in the studied population are low. Age and sex are important determinants for the development of CC, and with the EKG should guide echocardiogram performance.

Serological Diagnosis of Chronic Chagas Disease: Is It Time for a Change?

Chagas disease has spread to areas that are nonendemic for the disease with human migration. Since no single reference standard test is available, serological diagnosis of chronic Chagas disease requires at least two tests. New-generation techniques have significantly improved the accuracy of Chagas disease diagnosis by the use of a large mixture of recombinant antigens with different detection systems, such as chemiluminescence. The aim of the present study was to assess the overall accuracy of a new-generation kit, the Architect Chagas (cutoff, ≥1 sample relative light units/cutoff value [S/CO]), as a single technique for the diagnosis of chronic Chagas disease. The Architect Chagas showed a sensitivity of 100% (95% confidence interval [CI], 99.5 to 100%) and a specificity of 97.6% (95% CI, 95.2 to 99.9%). Five out of six false-positive serum samples were a consequence of cross-reactivity with Leishmania spp., and all of them achieved results of <5 S/CO. We propose the Architect Chagas as a single technique for screening in blood banks and for routine diagnosis in clinical laboratories. Only gray-zone and positive sera with a result of ≤6 S/CO would need to be confirmed by a second serological assay, thus avoiding false-positive sera and the problem of cross-reactivity with Leishmania species. The application of this proposal would result in important savings in the cost of Chagas disease diagnosis and therefore in the management and control of the disease.

[Update Chagas disease]

The constant migration flows have favored the presence of people with Chagas disease in regions traditionally regarded as non-endemic, such as North America, Europe, Asia and Oceania. This has forced both health authorities and professionals to be updated in order to respond to such a demand for assistance. Recent years have led to significant progress in the field of diagnosis and treatment of Chagas disease, one of the most neglected tropical diseases. Recent clinical trials are providing new evidence that makes the management of these patients, a constant challenge for the professionals involved. Innovative diagnostic tools and therapeutic regimens, allow us to face the future of Chagas disease with optimism.

Highly discordant serology against Trypanosoma cruzi in central Veracruz, Mexico: role of the antigen used for diagnostic

Background

Chagas disease is a parasitic disease caused by the protozoan parasite Trypanosoma cruzi. In Mexico, the burden of the disease is difficult to estimate and improving surveillance for Chagas disease is an important priority. We aimed here at determining the seroprevalence of T. cruzi infection in humans in a rural community in Veracruz.

Methods

Serum samples (196) were analyzed for T. cruzi infection using five enzyme-linked immunosorbent assay (ELISA) tests: two in-house tests based on crude parasite extract and three commercial ELISA kits. Because of highly discordant results, we further explored the importance of parasite antigens and strains by western-blot analysis.

Results

A total of 74 samples (37.7 %) were reactive with at least one ELISA, but discordance among tests was very high. The best agreement was between Chagatest recombinant and Chagatek ELISA (Kappa index = 0.798). The agreement between other combinations of tests ranged from 0.038 to 0.518. Discordant samples were confirmed by western-blot analysis using up to nine parasite strains, giving a seroprevalence of 33.7 %.

Conclusions

Commercial tests had a very limited ability to detect T. cruzi infection in the study population. In-house tests based on crude parasite antigens showed a greater sensitivity but were still unable to detect all cases of T. cruzi infection, even when based on a local parasite strain. The high seroprevalence confirmed the hyper-endemicity of T. cruzi infection in the region. Reliable epidemiological surveillance of Chagas disease will require the development of improved diagnostic tests.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-1072-2) contains supplementary material, which is available to authorized users.

Old and new challenges in Chagas disease

Chagas disease, caused by the parasite Trypanosoma cruzi, is a neglected disease, which can lead to cardiomyopathy, arrhythmias, megaviscera, and more rarely, polyneuropathy in up to 30-40% of patients around 20 to 30 years after acute infection. Although it is endemic in the Americas, global population movements mean that it can be located wherever migrants from endemic areas settle. The disease was first described 100 years ago and still challenges clinicians worldwide, since diagnostic, therapeutic, and prognostic methods remain insufficient. Furthermore, factors such as HIV co-infection, immunosuppressive drugs, transplantation, and neoplastic disease can alter the natural course of the infection. We present the case of a Bolivian woman with chronic T cruzi infection diagnosed at our clinic in Madrid, Spain, who subsequently developed non-Hodgkin lymphoma. Our report illustrates the challenges of an increasingly common infection seen in non-endemic countries, and highlights both daily management dilemmas and associated difficulties that arise.

Toxic Profile of Benznidazole in Patients with Chronic Chagas Disease: Risk Factors and Comparison of the Product from Two Different Manufacturers

Benznidazole is considered the first-line treatment option against Chagas disease. The major drawback of benznidazole is its toxicity profile. The main objectives of this study were to describe the adverse events (AEs) in patients with chronic Chagas disease treated with benznidazole, determine the risk factors involved and compare the toxic profiles of two different preparations of the drug from ELEA and Roche. A total of 746 patients were diagnosed with Chagas disease in a 5-year period, and of these 472 were treated with benznidazole. A high proportion of patients (n = 360 [76%]) suffered AEs, the most frequent being those related to hypersensitivity (52.9% of patients), headache (12.5%), and epigastric pain (10.4%). In 72 (12.7%) cases, treatment was discontinued. Overall, women had a higher incidence of AEs compared to men (81.3% versus 66%, P = 0.001) and were subject to higher levels of hypersensitivity-related events. Dermatological events, digestive tract manifestations, and general symptoms had a greater likelihood to appear around day 10 and neurological AEs around day 40 after starting treatment. With respect to liver function and hematological tests, the majority of patients did not suffer significant perturbation of liver enzymes or altered blood cell counts. However, 14 patients suffered from neutropenia, and 14 patients had aminotransferase levels that were more than four times the upper limit of the normal range. Patients treated with the ELEA benznidazole product experienced more arthromyalgia, neutropenia, and neurological disorders (mainly paresthesias) than those treated with the Roche product. Both drug products resulted in approximately the same percentage of permanent withdrawals.

Assessment of rectocolonic morphology and function in patients with Chagas disease in Barcelona (Spain)

The aim of this study was to determine the relationship between colonic symptoms, radiological abnormalities, and anorectal dysfunction in patients with Chagas disease. We performed a cross-sectional study of untreated patients diagnosed with Chagas disease. All patients were evaluated clinically (by a questionnaire for colonic symptoms based on Rome III criteria) and underwent a barium enema and anorectal manometry. A control group of patients with functional constipation and without Chagas disease was included in the study. Overall, 69 patients were included in the study: 42 patients were asymptomatic and 27 patients had abdominal symptoms according to Rome III criteria. Anorectal manometry showed a higher proportion of abnormalities in symptomatic patients than in asymptomatic ones (73% versus 21%, respectively; P < 0.0001). Megarectum was detected in a similar proportion in the different subgroups regardless of the presence of symptoms or abnormalities in anorectal functions. Among non-Chagas disease patients with functional constipation, 90% had an abnormal anorectal manometry study. Patients with Chagas disease present a high proportion of constipation with dyssynergic defecation in anorectal manometry but a low prevalence of impaired rectoanal inhibitory reflex, although these abnormalities may be nonspecific for Chagas disease. The presence of megarectum is a nonspecific finding.

Parasitic infections in travelers and immigrants: part I protozoa

ABSTRACT 

The growth in international commerce, travel and migration contribute to the global emergence of certain parasitic infections. Importation of vectors and food products may contribute to the emergence of protozoan infections in nonendemic countries. Infections such as malaria are potentially fatal, especially in nonimmune patients, and outcome depends largely on timely diagnosis and treatment. Diagnosis/management of imported parasitic infections may be complex especially as some patients may have underlying immunosuppressive conditions such as HIV infection. Major challenges concern the development of improved diagnostic techniques, safer/more effective drug therapies and identification of biological markers of progression and response to treatment. Imported parasitic diseases which may be transmitted vertically or through blood transfusion/organ donation could become a public health priority in the near future. Climate change may affect arthropod distribution and facilitate the spread of protozoan vector-borne diseases. The first part of this review focuses on protozoan infections in travelers and immigrants.

Tropical diseases screening in immigrant patients with human immunodeficiency virus infection in Spain

Latent parasitic infections can reactivate because of immunosuppression. We conducted a prospective observational study of all human immunodeficiency virus (HIV)-infected immigrants who visited the Infectious Diseases Department of the Hospital Universitari Vall d'Hebron, Barcelona, Spain, during June 2010-May 2011. Screening of the most prevalent tropical diseases (intestinal parasitosis, Chagas disease, leishmaniasis, malaria, schistosomiasis, and strongyloidiasis) was performed according to geographic origin. A total of 190 patients were included: 141 (74.2%) from Latin America, 41 (21.6%) from sub-Saharan Africa, and 8 (4.2%) from northern Africa. Overall, 36.8% (70 of 190) of the patients had at least one positive result for any parasitic disease: 5 patients with positive Trypanosoma cruzi serology, 11 patients with positive Schistosoma mansoni serology, 35 patients with positive Strongyloides stercoralis serology, 7 patients with positive Leishmania infantum serology, intestinal parasitosis were detected in 37 patients, malaria was diagnosed in one symptomatic patient. We propose a screening and management strategy of latent parasitic infections in immigrant patients infected with HIV.

Congenital transmission of Trypanosoma cruzi in non-endemic areas: evaluation of a screening program in a tertiary care hospital in Barcelona, Spain

The impact of Chagas disease is no longer restricted to endemic areas. The aim of this study is to evaluate a 2-year period of a vertical transmission screening program of Trypanosoma cruzi infection in a tertiary care hospital in Barcelona (Spain). Two enzyme-linked immunosorbent assays (recombinant and crude antigen) were performed in parallel to pregnant women at risk of T. cruzi infection. Discordant results were confirmed by a third diagnostic test. In the case of a positive result, the newborn was tested at birth and after 8 months of life. A total of 1,473 women met the inclusion criteria for the screening program with a resulting seroprevalence for T. cruzi of 3.5% (2.2-5.2% 95% confidence interval [95% CI]). One case of congenital infection was identified. Screening programs for vertically transmitted T. cruzi acute infection are beneficial in non-endemic areas for early detection and treatment of acute infection.