The Sero-Prevalence of Antibodies to Trypanosoma cruzi in Latin American Refugees and Immigrants to Canada

Hospitalization for Chagas Heart Disease in the United States From 2002 to 2017

This cross-sectional study examines characteristics and outcomes of estimated discharges for Chagas heart disease in the United States from 2002 to 2017.

Recognition and screening for Chagas disease in the USA

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, is a public health concern, mainly among countries in South and Central America. However, despite the large number of immigrants from endemic countries living in the USA, awareness of CD is poor in the medical community, and therefore it is significantly underdiagnosed. To avoid the catastrophic cardiac complications of CD and to prevent maternal-fetal transmission, widespread educational programs highlighting the need for diagnosis are urgently needed.

High sensitivity and reproducibility of in-house ELISAs using different genotypes of Trypanosoma cruzi

The adequate choice of Trypanosoma cruzi strains as antigen source for the diagnosis of Chagas disease is still controversial due to differences in terms of accuracy reported between different diagnostic tests. In this study was determined if the genetic variability between different genotypes of T. cruzi (TcI, TcII and TcIV) affect the final diagnosis of Chagas disease. The sensitivity and specificity index of in-house ELISA tests prepared with different T. cruzi strains were evaluated with chagasic and non-chagasic control sera and using the TESA-blot as a reference test. The results of this study revealed that the sensitivity index did not vary, with percentages of 100% for all strains in both tests. However, the specificity index for ELISA tests showed differences between 92% and 98%, but were reduced to 78%-89% when Leishmania-positive sera were included. All ELISAs and TESA-blot prepared with different antigens and the recombinant Wiener test were challenged in an endemic community for Chagas disease in Panama. Both ELISAs and TESA-blot recognized the same positive sera, corroborating the sensitivity indexes (100%) found with the control sera. The TESA-blot maintained the specificity index of 100% and did not display false positives. However, the recombinant Wiener test decreased its sensitivity to 81.25%.

[Anti-Trypanosoma cruzi antibodies in Latin American migrants in transit through the México- USA border]

INTRODUCTION

In recent years, American trypanosomiasis has become an emergent public health problem in countries receiving migrant populations such as México, USA, Canada or those in Europe.

OBJECTIVE

To analyze the prevalence of anti-Trypanosoma cruzi antibodies in Latin American migrants on their way to USA and Canada by means of serological techniques.

MATERIAL AND METHODS

ELISA and IHA were performed to detect anti-T. cruzi antibodies. Also, each participant filled out a socioeconomic questionnaire to determine the associated factors with seropositive cases, which could facilitate the transmission in the migrants' country of origin.

RESULTS

Total seroprevalence among the studied population was 20% (24/120). The highest prevalence was found in migrants from Guatemala with 37.5% (6/16), followed by Honduras (22.6%; 12/53), El Salvador (16%; 4/25), and México (8.7%, 3/23). From the total 120 surveyed migrants, 105 (87.5%) recognized the vector of Chagas' disease, and 62 (59%) assured having been bitten by it. Highly significant statistical associations were found between infection and the construction materials for walls and the presence of pets (dogs) inside houses (p≤0.01), as well as with the building materials for backyards, inadequate basic services, and animal breeding inside corrals built around dwellings (p≤0.05).

CONCLUSION

Non-endemic countries receiving migrants from endemic areas should enhance or develop better health policies to prevent transfusion-transmitted Chagas or congenital parasite transmission.

Heart Failure Secondary to Chagas Disease: an Emerging Problem in Non-endemic Areas

Chagas disease affects millions of people worldwide. Though the majority of infected individuals remain asymptomatic, approximately 30 % of patients progress to develop cardiac manifestations and eventual heart failure. While vectorial transmission occurs predominantly in South America, Central America, and Mexico, millions of people originally from these endemic regions immigrate to non-endemic countries in North America, Europe, and Asia. Outside of rare specialized centers, health-care providers lack experience diagnosing and treating this disease. This lack of experience likely leads to far fewer Chagas disease patients being diagnosed than what actually exist in non-endemic countries, with subsequent adverse effect on patient outcomes and health-care expenses. Underdiagnosis increases the risk of developing cardiomyopathy, associated heart failure, and life-threatening ventricular arrhythmias as the disease progresses.

Screening of living organ donors for endemic infections: Understanding the challenges and benefits of enhanced screening

Living organ donor candidates are screened for medical and psychosocial contraindications to donation. One important goal of this process is to prevent donor-derived infectious diseases transmissions. These transmissions are exceptionally rare, but have the potential to cause significant morbidity and mortality. The Organ Procurement and Transplantation Network now requires each recovery hospital to develop a protocol for evaluating living donors for tuberculosis and other geographically-defined endemic pathogens, including Trypanosoma cruzi (the causative pathogen of Chagas' disease), Strongyloides stercoralis, and West Nile Virus (WNV), in addition to universal screening for blood-borne pathogens. Enhanced screening requirements were developed in response to the changing epidemiology and endemicity of these diseases, as well as recent case reports of donor-derived disease transmission. Living organ donor disease screening presents a number of unique challenges to clinicians and policy-makers, including deciding which donors to test, which testing modality to use, when to test, and appropriate interpretation of results. This review will analyze the epidemiology of T. cruzi, S. stercoralis, and WNV, the assays available for screening for these diseases, and the subsequent impact on the living organ donor process . This article is protected by copyright. All rights reserved.

A global systematic review of Chagas disease prevalence among migrants

Human migration has been identified as a potential factor for increased Chagas disease risk and has transformed the disease from a Latin American problem to a global one. We conducted a systematic review of the scientific literature between 2004-2014 in order to: summarize recent seroprevalence estimates of Chagas disease among Latin American migrants, in both endemic and non-endemic settings; compare seroprevalence estimates in migrants to countrywide prevalence estimates; and identify risk factors for Chagas disease among migrants. A total of 320 studies were screened and 23 studies were included. We found evidence that the prevalence of Chagas disease is higher than expected in some migrant groups and that reliance on blood donor screening prevalence estimates underestimates the burden of disease. Overall there is a dearth of high quality epidemiologic studies on the prevalence of Chagas disease in migrants, especially among intra-regional migrants within Latin America. Given that this zoonotic disease cannot likely be eradicated, improved surveillance and reporting is vital to continuing control efforts. More accurate health surveillance of both Latin American migrants and the Chagas disease burden will help countries appropriately scale up their response to this chronic disease. Overall, improved estimates of Chagas disease among migrants would likely serve to highlight the real need for better screening, diagnostics, and treatment of individuals living with the disease.

The importance of the multidisciplinary approach to deal with the new epidemiological scenario of Chagas disease (global health)

There are currently two major factors that have modified the epidemiology of Chagas disease in the last decades: climate change and migration flows. In this new scenario, there are new challenges to control and prevent Trypanosoma cruzi infection in endemic countries, such as the control of a wider distribution of triatomine vectors or the reinforcement of vertical transmission programs. In non-endemic areas, few countries are aware of the emergence of this new disease and have established changes in their health systems. To address this new public health challenge, the priorities should be control programs to avoid new cases of T. cruzi infection acquired through vertical transmission, blood transfusion or organ transplant. In both, endemic and non-endemic areas, the international community and all the actors involved in Chagas disease must join efforts mainly in two directions: better management of the infection in affected individuals and more research to cover the knowledge gap mainly in physiopathology, diagnosis and treatment.

A case of vertical transmission of Chagas disease contracted via blood transfusion in Canada

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and is endemic in many countries in Latin America, where infected bugs of the Triatominea subfamily carry the parasite in the gut and transmit it to humans through fecal contamination of a bite. However, vertical transmission and transmission through blood transfusion and organ transplantation is well documented. Increasing immigration from endemic countries to North America has prompted blood operators, including Canadian Blood Services and Hema Quebec, to initiate blood donor testing for Chagas antibody. In the present report, an unusual case of vertical transmission from a mother, most likely infected through blood transfusion, and detected as part of a concurrent seroprevalence study in blood donors is described.

Globalization of Chagas Disease: A Growing Concern in Nonendemic Countries

Chagas disease, caused by the parasite Trypanosoma cruzi, is a major cause of morbidity and mortality in Central and South America. Initial infection and ensuing chronic infection often go undetected in the human host. High seroprevalence of T. cruzi infection is well documented in endemic areas. Designated as “a neglected tropical disease” by the World Health Organization, rural economically disadvantaged and marginalized populations in endemic countries traditionally have the highest rates of infection. As economic hardship, political instability, and the search for opportunity spur migration of infected humans from endemic to non-endemic areas of the world, blood bank data have documented rising seroprevalence of T. cruzi in traditionally nonendemic areas. In these areas, T. cruzi is transmitted through blood transfusion, organ transplantation, and maternal-fetal mechanisms. Increasing awareness of large numbers of infected immigrants in nonendemic countries, and the medical care they require, has focused attention on the need for strategic programs for screening affected populations, education of healthcare providers, and provision of necessary medical services for those infected. Physicians in nonendemic countries should be able to recognize signs and symptoms of acute and chronic Chagas disease as migration and globalization increase the burden of disease in non-endemic areas.

Review: surveillance of Chagas disease

After remarkable reduction in prevalence through regional elimination of domestic vectors, the central challenge of Chagas disease control is shifting towards interruption of the disease transmission by non-eliminable vectors in Latin America. Vector surveillance with community participation was cost-effective against the eliminable vectors. But the efforts often failed against the non-eliminable vectors due to lack of surveillance coverage or sustainability. For instance, in El Salvador and Honduras, the operational vector control personnel lost access to many communities under decentralized health systems. To cover wider areas lastingly, the countries implemented the surveillance systems involving non-specialists from locally embedded resources, such as local health services, schools and community leaders. From these experiences, this paper outlines a common structure of the current community-based surveillance systems, consisting of five fundamental sequential functions. To increase scalability and sustainability, four of the five functions could be delegated to the locally available human resources, and the surveillance systems can be integrated into the general health systems. Challenges at national and regional levels are discussed for further evolution of the surveillance systems.

Chagas disease among the Latin American adult population attending in a primary care center in Barcelona, Spain

Background/Aims

The epidemiology of Chagas disease, until recently confined to areas of continental Latin America, has undergone considerable changes in recent decades due to migration to other parts of the world, including Spain. We studied the prevalence of Chagas disease in Latin American patients treated at a health center in Barcelona and evaluated its clinical phase. We make some recommendations for screening for the disease.

Methodology/Principal Findings

We performed an observational, cross-sectional prevalence study by means of an immunochromatographic test screening of all continental Latin American patients over the age of 14 years visiting the health centre from October 2007 to October 2009. The diagnosis was confirmed by serological methods: conventional in-house ELISA (cELISA), a commercial kit (rELISA) and ELISA using T cruzi lysate (Ortho-Clinical Diagnostics) (oELISA). Of 766 patients studied, 22 were diagnosed with T. cruzi infection, showing a prevalence of 2.87% (95% CI, 1.6–4.12%). Of the infected patients, 45.45% men and 54.55% women, 21 were from Bolivia, showing a prevalence in the Bolivian subgroup (n = 127) of 16.53% (95% CI, 9.6–23.39%).

All the infected patients were in a chronic phase of Chagas disease: 81% with the indeterminate form, 9.5% with the cardiac form and 9.5% with the cardiodigestive form. All patients infected with T. cruzi had heard of Chagas disease in their country of origin, 82% knew someone affected, and 77% had a significant history of living in adobe houses in rural areas.

Conclusions

We found a high prevalence of T. cruzi infection in immigrants from Bolivia. Detection of T. cruzi–infected persons by screening programs in non-endemic countries would control non-vectorial transmission and would benefit the persons affected, public health and national health systems.

Chagas disease is a parasitic infection caused by the protozoan Trypanosoma cruzi, and is becoming an emerging health problem in non-endemic areas because of growing population movements. The clinical manifestations of chronic T. cruzi infection include the latent form (the indeterminate chronic form), the cardiac form, the digestive or cardiodigestive form, and sudden death. Therefore, many diagnoses of Chagas disease are based on epidemiological suspicion rather than on clinical signs and symptoms. This study showed that the prevalence of Chagas disease in Latin American patients attending at a health center in Barcelona is 2,87% and the highest prevalence was found among Bolivian patients (16,53%). All the infected patients were in a chronic phase of Chagas disease. Detection of T. cruzi–infected persons by screening programs in non-endemic countries would control non-vectorial transmission and would benefit the persons affected, public health and national health systems. The data obtained in this study and the experiences described elsewhere suggest that it is advisable to perform Chagas disease screening in non-endemic countries on all patients from continental Latin America who: (1)have a suggestive epidemiologic history, (2)are pregnant, (3)are immunosuppressed, (4)have symptoms suggestive of Chagas disease, or (5)request screening.

High prevalence of persistent parasitic infections in foreign-born, HIV-infected persons in the United States

BACKGROUND

Foreign-born, HIV-infected persons are at risk for sub-clinical parasitic infections acquired in their countries of origin. The long-term consequences of co-infections can be severe, yet few data exist on parasitic infection prevalence in this population.

METHODOLOGY/PRINCIPAL FINDINGS

This cross-sectional study evaluated 128 foreign-born persons at one HIV clinic. We performed stool studies and serologic testing for strongyloidiasis, schistosomiasis, filarial infection, and Chagas disease based on the patient's country of birth. Eosinophilia and symptoms were examined as predictors of helminthic infection. Of the 128 participants, 86 (67%) were male, and the median age was 40 years; 70 were Mexican/Latin American, 40 African, and 18 from other countries or regions. Strongyloides stercoralis antibodies were detected in 33/128 (26%) individuals. Of the 52 persons from schistosomiasis-endemic countries, 15 (29%) had antibodies to schistosome antigens; 7 (47%) had antibodies to S. haematobium, 5 (33%) to S. mansoni, and 3 (20%) to both species. Stool ova and parasite studies detected helminths in 5/85 (6%) persons. None of the patients tested had evidence of Chagas disease (n = 77) or filarial infection (n = 52). Eosinophilia >400 cells/mm(3) was associated with a positive schistosome antibody test (OR 4.5, 95% CI 1.1-19.0). The only symptom significantly associated with strongyloidiasis was weight loss (OR 3.1, 95% CI 1.4-7.2).

CONCLUSIONS/SIGNIFICANCE

Given the high prevalence of certain helminths and the potential lack of suggestive symptoms and signs, selected screening for strongyloidiasis and schistosomiasis or use of empiric antiparasitic therapy may be appropriate among foreign-born, HIV-infected patients. Identifying and treating helminth infections could prevent long-term complications.

Screening and treatment of chagas disease in organ transplant recipients in the United States: recommendations from the chagas in transplant working group

Donor-derived transmission of Trypanosoma cruzi, the etiologic agent of Chagas disease, has emerged as an issue in the United States over the past 10 years. Acute T. cruzi infection causes substantial morbidity and mortality in the posttransplant setting if not recognized and treated early. We assembled a working group of transplant infectious disease specialists, laboratory medicine specialists, organ procurement organization representatives and epidemiologists with expertise in Chagas disease. Based on review of published and unpublished data, the working group prepared evidence-based recommendations for donor screening, and follow-up testing and treatment of recipients of organs from infected donors. We advise targeted T. cruzi screening of potential donors born in Mexico, Central America and South America. Programs can consider transplantation of kidneys and livers from T. cruzi-infected donors with informed consent from recipients. However, we recommend against heart transplantation from infected donors. For other organs, we recommend caution based on the anticipated degree of immunosuppression. Our recommendations stress the need for systematic monitoring of recipients by polymerase chain reaction, and microscopy of buffy coat and advance planning for immediate antitrypanosomal treatment if recipient infection is detected. Data on management and outcomes of all cases should be collected to inform future guidelines and to assist in coordination with public health authorities.

Is SELDI-TOF a valid tool for diagnostic biomarkers?

The genome revolution is providing fresh insights into host and parasite genomes, and new tools are becoming available for examining host-parasite interactions at the proteome level. Technologies such as surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry (MS) can be applied to discover biomarkers (alterations in both host and parasite proteomes) associated with parasitic diseases. Such biomarkers can represent host proteins, fragments of host proteins or parasite proteins that appear in body fluids or tissues following infection. Individual biomarkers or biomarker patterns not only have diagnostic utility (e.g. in active disease, prognosis, tests of cure) but can also provide unique insights into the mechanisms underlying host responses and pathogenesis.

ELISA versus PCR for diagnosis of chronic Chagas disease: systematic review and meta-analysis

Background

Most current guidelines recommend two serological tests to diagnose chronic Chagas disease. When serological tests are persistently inconclusive, some guidelines recommend molecular tests. The aim of this investigation was to review chronic Chagas disease diagnosis literature and to summarize results of ELISA and PCR performance.

Methods

A systematic review was conducted searching remote databases (MEDLINE, LILACS, EMBASE, SCOPUS and ISIWeb) and full texts bibliography for relevant abstracts. In addition, manufacturers of commercial tests were contacted. Original investigations were eligible if they estimated sensitivity and specificity, or reliability -or if their calculation was possible - of ELISA or PCR tests, for chronic Chagas disease.

Results

Heterogeneity was high within each test (ELISA and PCR) and threshold effect was detected only in a particular subgroup. Reference standard blinding partially explained heterogeneity in ELISA studies, and pooled sensitivity and specificity were 97.7% [96.7%-98.5%] and 96.3% [94.6%-97.6%] respectively. Commercial ELISA with recombinant antigens studied in phase three investigations partially explained heterogeneity, and pooled sensitivity and specificity were 99.3% [97.9%-99.9%] and 97.5% [88.5%-99.5%] respectively. ELISA's reliability was seldom studied but was considered acceptable. PCR heterogeneity was not explained, but a threshold effect was detected in three groups created by using guanidine and boiling the sample before DNA extraction. PCR sensitivity is likely to be between 50% and 90%, while its specificity is close to 100%. PCR reliability was never studied.

Conclusions

Both conventional and recombinant based ELISA give useful information, however there are commercial tests without technical reports and therefore were not included in this review. Physicians need to have access to technical reports to understand if these serological tests are similar to those included in this review and therefore correctly order and interpret test results. Currently, PCR should not be used in clinical practice for chronic Chagas disease diagnosis and there is no PCR test commercially available for this purpose. Tests limitations and directions for future research are discussed.

Chagas disease: changes in knowledge and management

More than 100 years after the discovery of human American trypanosomiasis by Carlos Chagas, our knowledge and management of the disease are profoundly changing. Substantial progress made by disease control programmes in most endemic areas contrasts with persisting difficulties in the Gran Chaco region in South America and the recent emergence of the disease in non-endemic areas because of population movements. In terms of pathogenesis, major discoveries have been made about the life cycle and genomics of Trypanosoma cruzi, and the role of the parasite itself in the chronic phase of the disease. From a clinical perspective, a growing number of arguments have challenged the notion of an indeterminate phase, and suggest new approaches to manage patients. New methods such as standardised PCR will be necessary to ensure follow-up of this chronic infection. Although drugs for treatment of Chagas disease are limited, poorly tolerated, and not very effective, treatment indications are expanding. The results of the Benznidazole Evaluation For Interrupting Trypanosomiasis (BENEFIT) trial in 2012 will also help to inform treatment. Mobilisation of financial resources to fund research on diagnosis and randomised controlled trials of treatment are international health priorities.

Chagas disease: a Latin American health problem becoming a world health problem

Political repression and/or economic stagnation stimulated the flow of migration from the 17 Latin American countries endemic for Chagas disease to developed countries. Because of this migration, Chagas disease, an autochthonous disease of the Continental Western Hemisphere is becoming a global health problem. In 2006, 3.8% of the 80,522 immigrants from those 17 countries to Australia were likely infected with Trypanosoma cruzi. In Canada in 2006, 3.5% of the 156,960 immigrants from Latin America whose country of origin was identified were estimated to have been infected. In Japan in 2007, there were 80,912 immigrants from Brazil, 15,281 from Peru, and 19,413 from other South American countries whose country of origin was not identified, a portion of whom may have been also infected. In 15 countries of Europe in 2005, excluding Spain, 2.9% of the 483,074 legal Latin American immigrants were estimated to be infected with T. cruzi. By 2008, Spain had received 1,678,711 immigrants from Latin American endemic countries; of these, 5.2% were potentially infected with T. cruzi and 17,390 may develop Chagas disease. Further, it was estimated that 24-92 newborns delivered by South American T. cruzi infected mothers in Spain may have been congenitally infected with T. cruzi in 2007. In the USA we estimated that 1.9% of approximately 13 million Latin American immigrants in 2000, and 2% of 17 million in 2007, were potentially infected with T. cruzi. Of these, 49,157 and 65,133 in 2000 and 2007 respectively, may have or may develop symptoms and signs of chronic Chagas disease. Governments should implement policies to prevent donations of blood and organs from T. cruzi infected donors. In addition, an infrastructure that assures detection and treatment of acute and chronic cases as well as congenital infection should be developed.

Identification of novel diagnostic serum biomarkers for Chagas' disease in asymptomatic subjects by mass spectrometric profiling

More than 10 million people are thought to be infected with Trypanosoma cruzi, primarily in the Americas. The clinical manifestations of Chagas' disease (CD) are variable, but most subjects remain asymptomatic for decades. Only 15 to 30% eventually develop terminal complications. All current diagnostic tests have limitations. New approaches are needed for blood bank screening as well as for improved diagnosis and prognosis. Sera from subjects with asymptomatic CD (n = 131) were compared to those from uninfected controls (n = 164) and subjects with other parasitic diseases (n = 140), using protein array mass spectrometry. To identify biomarkers associated with CD, sera were fractionated by anion-exchange chromatography and bound to two commercial ProteinChip array chemistries: WCX2 and IMAC3. Multiple candidate biomarkers were found in CD sera (3 to 75.4 kDa). Algorithms employing 3 to 5 of these biomarkers achieved up to 100% sensitivity and 98% specificity for CD. The biomarkers most useful for diagnosis were identified and validated. These included MIP1 alpha, C3a anaphylatoxin, and unusually truncated forms of fibronectin, apolipoprotein A1 (ApoA1), and C3. An antipeptide antiserum against the 28.9-kDa C terminus of the fibronectin fragment achieved good specificity (90%) for CD in a Western blot format. We identified full-length ApoA1 (28.1 kDa), the major structural and functional protein component of high-density lipoprotein (HDL), as an important negative biomarker for CD, and relatively little full-length ApoA1 was detected in CD sera. This work provides proof of principle that both platform-dependent (i.e., mass spectrometry-based) and platform-independent (i.e., Western blot) tests can be generated using high-throughput mass profiling.

Prevalence, clinical staging and risk for blood-borne transmission of Chagas disease among Latin American migrants in Geneva, Switzerland

Background

Migration of Latin Americans to the USA, Canada and Europe has modified Chagas disease distribution, but data on imported cases and on risks of local transmission remain scarce. We assessed the prevalence and risk factors for Chagas disease, staged the disease and evaluated attitudes towards blood transfusion and organ transplant among Latin American migrants in Geneva, Switzerland.

Methodology/Principal Findings

This cross-sectional study included all consecutive Latin American migrants seeking medical care at a primary care facility or attending two Latino churches. After completing a questionnaire, they were screened for Chagas disease with two serological tests (Biomérieux ELISA cruzi; Biokit Bioelisa Chagas). Infected subjects underwent a complete medical work-up. Predictive factors for infection were assessed by univariate and multivariate logistic regression analysis.1012 persons (females: 83%; mean age: 37.2 [SD 11.3] years, Bolivians: 48% [n = 485]) were recruited. 96% had no residency permit. Chagas disease was diagnosed with two positive serological tests in 130 patients (12.8%; 95%CI 10.8%–14.9%), including 127 Bolivians (26.2%; 95%CI 22.3%–30.1%). All patients were in the chronic phase, including 11.3% with cardiac and 0.8% with digestive complications. Predictive factors for infection were Bolivian origin (OR 33.2; 95%CI 7.5–147.5), reported maternal infection with T. cruzi (OR 6.9; 95%CI 1.9–24.3), and age older than 35 years (OR 6.7; 95%CI 2.4–18.8). While 22 (16.9%) infected subjects had already donated blood, 24 (18.5%) and 34 (26.2%) considered donating blood and organs outside Latin America, respectively.

Conclusions

Chagas disease is highly prevalent among Bolivian migrants in Switzerland. Chronic cardiac and digestive complications were substantial. Screening of individuals at risk should be implemented in nonendemic countries and must include undocumented migrants.

Chagas disease, a parasitic disease caused by Trypanosoma cruzi, is a leading cause of cardiac and digestive tract disorders in Mexico, Central and South America. An increasing number of cases have recently been reported in North America and Europe due to international human migration, but data outside Latin America remains scarce. This study showed that Chagas disease is an emerging health problem in Switzerland, affecting a substantial proportion of Latin American migrants (13%). Persons at increased risk of infection were Bolivian, older than 35 years or had a mother infected with T. cruzi. Early signs of cardiac or digestive tract disease were found in one out of six infected patients. The risk of local transmission by blood transfusion or organ transplant was illustrated by the frequent willingness expressed by patients to donate blood or organs in Switzerland. The authors recommend the screening of persons at risk of infection and the diffusion of appropriate information to the medical community to increase awareness of this emerging health problem. Considering that affected persons frequently lack health insurance in Switzerland, a facilitated access to medical care is an important step towards better recognition and management of Chagas disease.

Epidemiology of Chagas disease in non-endemic countries: the role of international migration

Human infection with the protozoa Trypanosoma cruzi extends through North, Central, and South America, affecting 21 countries. Most human infections in the Western Hemisphere occur through contact with infected bloodsucking insects of the triatomine species. As T. cruzi can be detected in the blood of untreated infected individuals, decades after infection took place; the infection can be also transmitted through blood transfusion and organ transplant, which is considered the second most common mode of transmission for T. cruzi. The third mode of transmission is congenital infection. Economic hardship, political problems, or both, have spurred migration from Chagas endemic countries to developed countries. The main destination of this immigration is Australia, Canada, Spain, and the United States. In fact, human infection through blood or organ transplantation, as well as confirmed or potential cases of congenital infections has been described in Spain and in the United States. Estimates reported here indicates that in Australia in 2005-2006, 1067 of the 65,255 Latin American immigrants (16 per 1000) may be infected with T. cruzi, and in Canada, in 2001, 1218 of the 131,135 immigrants (9 per 1000) whose country of origin was identified may have been also infected. In Spain, a magnet for Latin American immigrants since the 2000, 6141 of 38,777 to 339,954 [corrected] legal immigrants in 2003 (25 per 1000), could be infected. In the United States, 56,028 to 357,205 of the 7,20 million, legal immigrants (8 to 50 per 1000), depending on the scenario, from the period 1981-2005 may be infected with T. cruzi. On the other hand, 33,193 to 336,097 of the estimated 5,6 million undocumented immigrants in 2000 (6 to 59 per 1000) could be infected. Non endemic countries receiving immigrants from the endemic ones should develop policies to protect organ recipients from T. cruzi infection, prevent tainting the blood supply with T. cruzi, and implement secondary prevention of congenital Chagas disease.

Mother-to-Child Transmission of Chagas’ Disease in North America: Why Don’t We Do More?

OBJECTIVES

Mothers with Chagas' disease can transmit Trypanosoma cruzi to their fetuses, who often become carriers of the infection and are then at risk of developing severe cardiac disease later in the course of their lives. If identified early enough after birth, the infected newborns can be treated and cured. Our objective was to review the data available in Canada, Mexico, and the United States and to discuss the need for prevention programs.

METHODS

We reviewed the literature and estimated the number of seropositive mothers and newborns infected by T. cruzi.

RESULTS

We estimate that about 40,000 pregnant women and 2,000 newborns are likely to be infected by T. cruzi in North America. We have not identified any ongoing prevention programs.

CONCLUSIONS

Mother-to-child transmission of T. cruzi has all the characteristics required to be a public health priority, as it is relatively frequent, severe, identifiable, and treatable. In reality, it is a neglected disease and a missed opportunity. It is urgent to better understand the epidemiology of mother-to-child transmission of T. cruzi in North America and to develop effective prevention programs.