Early molecular diagnosis of acute Chagas disease after transplantation with organs from Trypanosoma cruzi-infected donors

Chagas disease in immunocompromised patients

SUMMARYAs Chagas disease remains prevalent in the Americas, it is important that healthcare professionals and researchers are aware of the screening, diagnosis, monitoring, and treatment recommendations for the populations of patients they care for and study. Management of Trypanosoma cruzi infection in immunocompromised hosts is challenging, particularly because, regardless of antitrypanosomal treatment status, immunocompromised patients with Chagas disease are at risk for T. cruzi reactivation, which can be lethal. Evidence-based practices to prevent and manage T. cruzi reactivation vary depending on the type of immunocompromise. Here, we review available data describing Chagas disease epidemiology, testing, and management practices for various populations of immunocompromised individuals, including people with HIV and patients undergoing solid organ and hematopoietic stem cell transplantation.

Quantitative PCR as a marker for preemptive therapy and its role in therapeutic control in Trypanosoma cruzi/HIV coinfection

BACKGROUND

Trypanosoma cruzi and HIV coinfection can evolve with depression of cellular immunity and increased parasitemia. We applied quantitative PCR (qPCR) as a marker for preemptive antiparasitic treatment to avoid fatal Chagas disease reactivation and analyzed the outcome of treated cases.

METHODOLOGY

This mixed cross-sectional and longitudinal study included 171 Chagas disease patients, 60 coinfected with HIV. Of these 60 patients, ten showed Chagas disease reactivation, confirmed by parasites identified in the blood, cerebrospinal fluid, or tissues, 12 exhibited high parasitemia without reactivation, and 38 had low parasitemia and no reactivation.

RESULTS

We showed, for the first time, the success of the timely introduction of benznidazole in the non-reactivated group with high levels of parasitemia detected by qPCR and the absence of parasites in reactivated cases with at least 58 days of benznidazole. All HIV+ patients with or without reactivation had a 4.0-5.1 higher chance of having parasitemia than HIV seronegative cases. A positive correlation was found between parasites and viral loads. Remarkably, treated T. cruzi/HIV-coinfected patients had 77.3% conversion from positive to negative parasitemia compared to 19.1% of untreated patients. Additionally, untreated patients showed ~13.6 times higher Odds Ratio of having positive parasitemia in the follow-up period compared with treated patients. Treated and untreated patients showed no differences regarding the evolution of Chagas disease. The main factors associated with all-cause mortality were higher parasitemia, lower CD4 counts/μL, higher viral load, and absence of antiretroviral therapy.

CONCLUSION

We recommend qPCR prospective monitoring of T. cruzi parasitemia in HIV+ coinfected patients and point out the value of pre-emptive therapy for those with high parasitemia. In parallel, early antiretroviral therapy introduction is advisable, aiming at viral load control, immune response restoration, and increasing survival. We also suggest an early antiparasitic treatment for all coinfected patients, followed by effectiveness analysis alongside antiretroviral therapy.

Quantitative PCR-Based Diagnosis and Follow-up of Chagas Disease Primary Infection After Solid Organ Transplant: A Multicentre Study

Chagas disease in solid organ transplant recipients may present as a primary infection (PI). Early detection is crucial for timely treatment. This is the largest observational multicentre study evaluating qPCR for early diagnosis and treatment monitoring of PI in seronegative recipients of organs from seropositive donors. Of 34 patients admitted at 5 health centers, PI was detected by qPCR in 8 (23.5%) within a posttransplant period of 40 days (interquartile range [IQR], 31-50 days). No PI was detected by the Strout test or clinical symptoms/signs. All patients had favorable treatment outcome with negative qPCR 31 days (IQR, 18-35 days) after treatment, with no posttreatment relapse episodes.

Minimizing the Risk of Donor-Derived Events and Maximizing Organ Utilization Through Education and Policy Development

Herein, we review the current knowledge of donor-derived disease and current US Organ Procurement and Transplantation Network policies to minimize the risk. During the process, we also consider actions to further mitigate the risk of donor-derived disease. The overarching goal is to provide an infectious disease perspective on the complex decision of organ acceptance for transplant programs and candidates.

Validation of the NAT Chagas IVD Kit for the Detection and Quantification of Trypanosoma cruzi in Blood Samples of Patients with Chagas Disease

In the absence of validated biomarkers to control the cure of Chagas disease, PCR-based diagnosis is being used as the main tool for an early indication of therapeutic failure. However, since it is considered a technique of complex reproducibility, mainly due to difficulties in establishing accurate controls to guarantee the quality of the reaction, the use of PCR for Chagas disease diagnosis is restricted to specialized centers. In an effort to disseminate the molecular diagnosis of Chagas disease and its applications, new diagnostic kits based on qPCR have been made available in the market in recent years. Here, we show the results of the validation of the NAT Chagas kit (Nucleic Acid Test for Chagas Disease) for the detection and quantification of T. cruzi in blood samples of patients suspected of Chagas disease infection. The kit, composed of a TaqMan duplex reaction targeting the T. cruzi satellite nuclear DNA and an exogenous internal amplification control, presented a reportable range from 10⁴ to 0.5 parasite equivalents/mL and a limit of detection (LOD) of 0.16 parasite equivalents/mL of blood. In addition, the NAT Chagas kit detected T. cruzi belonging to all six discrete typing units (DTUs-TcI to TcVI), similarly to the in-house real-time PCR performed with commercial reagents, which has been selected as the best performance assay in the international consensus for the validation of qPCR for Chagas disease. In the clinical validation presented here, the kit showed 100% sensitivity and 100% specificity when compared to the consensus in-house real-time PCR assay. Thus, the NAT Chagas kit, which is produced entirely in Brazil under the international standards of good manufacturing practices (GMP), appears as an excellent alternative to enable the molecular diagnosis of Chagas disease in public and private diagnostic centers, as well as to facilitate the monitoring of patients under etiological treatment participating in clinical trials.

Transplantation for chagas' disease: closing the knowledge gap

PURPOSE OF THE REVIEW

This review examines the most recent literature on the epidemiology and treatment of Chagas Disease and the risk of Chagas Disease Reactivation and donor-derived disease in solid organ transplant recipients.

RECENT FINDINGS

Chagas disease is caused by infection with the parasite Trypansoma cruzi . In nonendemic countries the disease is seen primarily in immigrants from Mexico, Central America and South America where the disease is endemic. Benznidazole or nifurtimox can be used for treatment. Posaconazole and fosravuconazole did not provide any additional benefit compared to benznidazole alone or in combination. A phase 2 randomized controlled trial suggests that shorter or reduced dosed regimes of benznidazole could be used. Based on a large randomized controlled trial, benznidazole is unlikely to have a significant preventive effect for established Chagas cardiomyopathy. Transplantation has become the treatment of choice for individuals with refractory Chagas cardiomyopathy. Cohort studies show similar posttransplant outcomes for these patients compared to other indications. Transplant candidates and donors with chronic T. cruzi infection are at risk for Chagas disease reactivation and transmitting infection. Screening them via serology is the first line of prevention. Recipients with chronic infection and those receiving organs from infected donors should undergo sequential monitoring with polymerase chain reaction for early detection of reactivation and preemptive treatment with antitrypanosomal therapy.

SUMMARY

Patients with chronic T. cruzi infection can be safely transplanted and be noncardiac organ donors.

Aplastic Anemia and Chagas Disease: T. cruzi Parasitemia Monitoring by Quantitative PCR and Preemptive Antiparasitic Therapy

Background: Aplastic anemia is a rare and life-threatening condition, seldomly witnessed concomitantly with Chagas disease. We aim to discuss the management of these patients under risk of chronic Chagas disease reactivation (CDR), a severe condition with a high morbimortality that occurs in chronic Chagas disease patients under immunosuppression. Case reports: Trypanosoma cruzi (T. cruzi) parasitemia was monitored in three patients for 4−58 months by conventional PCR (cPCR), quantitative PCR (qPCR), microhematocrit/buffy coat, blood culture, and/or xenodiagnosis. One patient received antiparasitic treatment (benznidazole) and the other received allopurinol. Although parasitemia was controlled during and after benznidazole treatment at 300 mg/d for 51 days, in one patient, hematologic parameters worsened continuously before, during, and after treatment. Allopurinol led only to the temporary suppression of T. cruzi parasitemia in the second patient, but after danazol and hematological improvement, parasitemia became undetectable until the end of monitoring. Discussion and Conclusion: Unexpected undetectable or low parasitemia by cPCR/qPCR was reported. We show that the monitoring of parasitemia by qPCR and the use of preemptive therapy when the parasitemia was positive proved to be beneficial to our patients. As a result of the toxicity of more effective antiparasitics, shorter regimens of benznidazole or less toxic drugs in preemptive therapy are options that deserve future studies.

Gold Nanoshells-Based Lateral Flow Assay for the Detection of Chagas Disease at the Point-of-Care

Chagas disease is a neglected parasitic infection and a major public health problem in the Americas. It remains underdiagnosed in the United States and internationally due to the lack of affordable testing and disparities in healthcare, particularly for those most at risk. We describe a proof-of-concept lateral flow immunoassay employing a recombinant Chagas multiantigen conjugated to gold nanoshells (AuNS) to detect circulating human anti-Chagas IgG antibodies. This is one of the first lateral flow immunoassays to capitalize on the larger surface area of AuNS compared with nanoparticles that can help amplify low-magnitude signals. Results were compared with 42 positive and negative Chagas serum samples, of which a subset of 27 samples was validated against an ELISA (Hemagen®). The sensitivity and specificity of our assay were 83% and 95%, respectively. These results suggest that an AuNS-based rapid testing for Chagas disease could facilitate in-field screening/diagnosis with a performance comparable to commercial methods.

Parasitological, serological and molecular diagnosis of acute and chronic Chagas disease: from field to laboratory

There is no consensus on the diagnostic algorithms for many scenarios of Trypanosoma cruzi infection, which hinders the establishment of governmental guidelines in endemic and non-endemic countries. In the acute phase, parasitological methods are currently employed, and standardised surrogate molecular tests are being introduced to provide higher sensitivity and less operator-dependence. In the chronic phase, IgG-based serological assays are currently used, but if a single assay does not reach the required accuracy, PAHO/WHO recommends at least two immunological tests with different technical principles. Specific algorithms are applied to diagnose congenital infection, screen blood and organ donors or conduct epidemiological surveys. Detecting Chagas disease reactivation in immunosuppressed individuals is an area of increasing interest. Due to its neglect, enhancing access to diagnosis of patients at risk of suffering T. cruzi infection should be a priority at national and regional levels.

Emerging and reemerging forms of Trypanosoma cruzi transmission

This review aims to update and discuss the main challenges in controlling emergent and reemergent forms of Trypanosoma cruzi transmission through organ transplantation, blood products and vertical transmission in endemic and non-endemic areas as well as emergent forms of transmission in endemic countries through contaminated food, currently representing the major cause of acute illness in several countries. As a neglected tropical disease potentially controllable with a major impact on morbimortality and socioeconomic aspects, Chagas disease (CD) was approved at the WHO global plan to interrupt four transmission routes by 2030 (vector/blood transfusion/organ transplant/congenital). Implementation of universal or target screening for CD are highly recommended in blood banks of non-endemic regions; in organ transplants donors in endemic/non-endemic areas as well as in women at risk from endemic areas (reproductive age women/pregnant women-respective babies). Moreover, main challenges for surveillance are the application of molecular methods for identification of infected babies, donor transmitted infection and of live parasites in the food. In addition, the systematic recording of acute/non-acute cases and transmission sources is crucial to establish databases for control and surveillance purposes. Remarkably, antiparasitic treatment of infected reproductive age women and infected babies is essential for the elimination of congenital CD by 2030.

Clinical profile and mortality in patients with T. cruzi/HIV co-infection from the multicenter data base of the "Network for healthcare and study of Trypanosoma cruzi/HIV co-infection and other immunosuppression conditions"

OBJECTIVE

Chagas disease (CD) globalization facilitated the co-infection with Human Immunodeficiency Virus (HIV) in endemic and non-endemic areas. Considering the underestimation of Trypanosoma cruzi (T. cruzi)-HIV co-infection and the risk of life-threatening Chagas Disease Reactivation (CDR), this study aimed to analyze the major co-infection clinical characteristics and its mortality rates.

METHODS

This is a cross-sectional retrospective multicenter study of patients with CD confirmed by two serological or one parasitological tests, and HIV infection confirmed by immunoblot. CDR was diagnosed by direct microscopy with detection of trypomastigote forms in the blood or other biological fluids and/or amastigote forms in inflammatory lesions.

RESULTS

Out of 241 patients with co-infection, 86.7% were from Brazil, 47.5% had <200 CD4+ T cells/μL and median viral load was 17,000 copies/μL. Sixty CDR cases were observed. Death was more frequent in patients with reactivation and was mainly caused by CDR. Other causes of death unrelated to CDR were the manifestation of opportunistic infections in those with Acquired Immunodeficiency Syndrome. The time between the co-infection diagnosis to death was shorter in patients with CDR. Lower CD4+ cells count at co-infection diagnosis was independently associated with reactivation. Similarly, lower CD4+ cells numbers at co-infection diagnosis and male sex were associated with higher lethality in CDR. Additionally, CD4+ cells were lower in meningoencephalitis than in myocarditis and milder forms.

CONCLUSION

This study showed major features on T. cruzi-HIV co-infection and highlighted the prognostic role of CD4+ cells for reactivation and mortality. Since lethality was high in meningoencephalitis and all untreated patients died shortly after the diagnosis, early diagnosis, immediate antiparasitic treatment, patient follow-up and epidemiological surveillance are essentials in T. cruzi/HIV co-infection and CDR managements.

Endemic parasitic infections in donors and recipients of stem cell and solid organ transplants: focus on strongyloidiasis and Chagas disease

PURPOSE OF REVIEW

The aim of the article is to review recent recommendations on the management of Strongyloidiasis and Chagas disease (ChD) in the context of stem-cell or solid-organ transplantation.

RECENT FINDINGS

An update on laboratory screening, detection of acute disease or reactivation and recommended preventive or therapeutic options in the transplant recipients and donors is presented. Recent epidemiological data showing new estimates on the worldwide burden of both diseases and changes in the classical distribution around the globe should increase awareness and will impact the evaluation and management of transplant recipients and donors in endemic and nonendemic regions.

SUMMARY

Strongyloidiasis and ChD are potentially life threatening if unnoticed in the context of stem-cell or solid-organ transplantation and should be considered in endemic and nonendemic areas. Effective strategies for detection, monitoring, prevention and management are available for both diseases.

Toward the Establishment of a Single Standard Curve for Quantification of Trypanosoma cruzi Natural Populations Using a Synthetic Satellite Unit DNA Sequence

Accurate diagnostic tools and surrogate markers of parasitologic response to treatment are needed for managing Chagas disease. Quantitative real-time PCR (qPCR) is used for treatment monitoring, but variability in copy dosage and sequences of molecular target genes among different Trypanosoma cruzi strains limit the precision of quantitative measures. To improve qPCR quantification accuracy, we designed and evaluated a synthetic DNA molecule containing a satellite DNA (satDNA) repeat unit as standard for quantification of T. cruzi loads in clinical samples, independently of the parasite strain. Probit regression analysis established for Dm28c (TcI) and CL-Brener (TcVI) stocks similar 95% limit of detection values [0.903 (0.745 to 1.497) and 0.667 (CI, 0.113 to 3.927) copy numbers/μL, respectively] when synthetic DNA was the standard for quantification, allowing direct comparison of loads in samples infected with different discrete typing units. This standard curve was evaluated in 205 samples (38 acute oral and 19 chronic Chagas disease patients) from different geographical areas infected with various genotypes, including samples obtained during treatment follow-up; high agreement with parasitic load trends using standard curves based on DNA extracted from spiked blood with counted parasites was obtained. This qPCR-based quantification strategy will be a valuable tool in phase 3 clinical trials, to follow up patients under treatment or at risk of reactivation, and in experimental models using different parasite strains.

Development and Evaluation of a Three-Dimensional Printer-Based DNA Extraction Method Coupled to Loop Mediated Isothermal Amplification for Point-of-Care Diagnosis of Congenital Chagas Disease in Endemic Regions

Vertical transmission of Trypanosomacruzi is the cause of congenital Chagas disease, a re-emerging infectious disease that affects endemic and nonendemic regions alike. An early diagnosis is crucial because prompt treatment achieves a high cure rate, precluding evolution to symptomatic chronic Chagas disease. However, early diagnosis involves low-sensitive parasitologic assays, making necessary serologic confirmation after 9 months of life. With the aim of implementing early diagnostic strategies suitable for minimally equipped laboratories, a T. cruzi-loop-mediated isothermal amplification (LAMP) prototype was coupled with an automated DNA-extraction device repurposed from a three-dimensional printer (PrintrLab). The whole process takes <3 hours to yield a result, with an analytical sensitivity of 0.1 to 2 parasite equivalents per milliliter, depending on the T. cruzi strain. Twenty-five blood samples from neonates born to seropositive mothers were tested blindly. In comparison to quantitative real-time PCR, the PrintrLab-LAMP dual strategy showed high agreement, while both molecular-based methodologies yielded optimal sensitivity and specificity with respect to microscopy-based diagnosis of congenital Chagas disease. PrintrLab-LAMP detected all 10 congenitally transmitted T. cruzi infections, showing promise for point-of-care early diagnosis of congenital Chagas disease.

Extracellular Vesicles in Trypanosomatids: Host Cell Communication

Trypanosoma cruzi, Trypanosoma brucei and Leishmania (Trypanosomatidae: Kinetoplastida) are parasitic protozoan causing Chagas disease, African Trypanosomiasis and Leishmaniases worldwide. They are vector borne diseases transmitted by triatomine bugs, Tsetse fly, and sand flies, respectively. Those diseases cause enormous economic losses and morbidity affecting not only rural and poverty areas but are also spreading to urban areas. During the parasite-host interaction, those organisms release extracellular vesicles (EVs) that are crucial for the immunomodulatory events triggered by the parasites. EVs are involved in cell-cell communication and can act as important pro-inflammatory mediators. Therefore, interface between EVs and host immune responses are crucial for the immunopathological events that those diseases exhibit. Additionally, EVs from these organisms have a role in the invertebrate hosts digestive tracts prior to parasite transmission. This review summarizes the available data on how EVs from those medically important trypanosomatids affect their interaction with vertebrate and invertebrate hosts.

Trypanosoma cruzi loop-mediated isothermal amplification (Trypanosoma cruzi Loopamp) kit for detection of congenital, acute and Chagas disease reactivation

A Trypanosoma cruzi Loopamp kit was recently developed as a ready-to-use diagnostic method requiring minimal laboratory facilities. We evaluated its diagnostic accuracy for detection of acute Chagas disease (CD) in different epidemiological and clinical scenarios. In this retrospective study, a convenience series of clinical samples (venous blood treated with EDTA or different stabilizer agents, heel-prick blood in filter paper or cerebrospinal fluid samples (CSF)) from 30 infants born to seropositive mothers (13 with congenital CD and 17 noninfected), four recipients of organs from CD donors, six orally-infected cases after consumption of contaminated guava juice and six CD patients coinfected with HIV at risk of CD reactivation (N = 46 patients, 46 blood samples and 1 CSF sample) were tested by T. cruzi Loopamp kit (Tc LAMP) and standardized quantitative real-time PCR (qPCR). T. cruzi Loopamp accuracy was estimated using the case definition in the different groups as a reference. Cohen's kappa coefficient (κ) was applied to measure the agreement between Tc LAMP (index test) and qPCR (reference test). Sensitivity and specificity of T. cruzi Loopamp kit in blood samples from the pooled clinical groups was 93% (95% CI: 77-99) and 100% (95% CI: 80-100) respectively. The agreement between Tc LAMP and qPCR was almost perfect (κ = 0.92, 95% CI: 0.62-1.00). The T. cruzi Loopamp kit was sensitive and specific for detection of T. cruzi infection. It was carried out from DNA extracted from peripheral blood samples (via frozen EDTA blood, guanidine hydrochloride-EDTA blood, DNAgard blood and dried blood spots), as well as in CSF specimens infected with TcI or TcII/V/VI parasite populations. The T. cruzi Loopamp kit appears potentially useful for rapid detection of T. cruzi infection in congenital, acute and CD reactivation due to HIV infection.

Tissue and blood protozoa including toxoplasmosis, Chagas disease, leishmaniasis, Babesia, Acanthamoeba, Balamuthia, and Naegleria in solid organ transplant recipients- Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of tissue and blood protozoal infections in the pre- and post-transplant period. Significant new developments in the field have made it necessary to divide the previous single guideline published in 2013 into two sections, with the intestinal parasites separated from this guideline devoted to tissue and blood protozoa. The current update reflects the increased focus on donor screening and risk-based recipient monitoring for parasitic infections. Increased donor testing has led to new recommendations for recipient management of Toxoplasma gondii and Trypanosoma cruzi. Molecular diagnostics have impacted the field, with access to rapid diagnostic testing for malaria and polymerase chain reaction testing for Leishmania. Changes in Babesia treatment regimens in the immunocompromised host are outlined. The risk of donor transmission of free-living amebae infection is reviewed. Changing immigration patterns and the expansion of transplant medicine in developing countries has contributed to the recognition of parasitic infections as an important threat to transplant outcomes. Medications such as benznidazole and miltefosine are now available to US prescribers as access to treatment of tissue and blood protozoa is increasingly prioritized.

Chagas disease as example of a reemerging parasite

Trypanosoma cruzi, the protozoan that causes Chagas disease, is primarily transmitted by three main Triatomine vectors in endemic areas. However, the infection has become a potential emerging disease because the vector is found in non-endemic areas, there is migration of infected asymptomatic people that can infect the vector, become blood donors, or pass the disease vertically (congenital infections). Lastly, the disease can be acquired through contaminated food (oral transmission). This review will present the different transmission pathways, clinical manifestations, diagnostic modalities and treatment considerations of Chagas disease.

Infectious Disease Transmission in Solid Organ Transplantation: Donor Evaluation, Recipient Risk, and Outcomes of Transmission

In 2016, the Transplantation Society of Australia and New Zealand, with the support of the Australian Government Organ and Tissue authority, commissioned a literature review on the topic of infectious disease transmission from deceased donors to recipients of solid organ transplants. The purpose of this review was to synthesize evidence on transmission risks, diagnostic test characteristics, and recipient management to inform best-practice clinical guidelines. The final review, presented as a special supplement in Transplantation Direct, collates case reports of transmission events and other peer-reviewed literature, and summarizes current (as of June 2017) international guidelines on donor screening and recipient management. Of particular interest at the time of writing was how to maximize utilization of donors at increased risk for transmission of human immunodeficiency virus, hepatitis C virus, and hepatitis B virus, given the recent developments, including the availability of direct-acting antivirals for hepatitis C virus and improvements in donor screening technologies. The review also covers emerging risks associated with recent epidemics (eg, Zika virus) and the risk of transmission of nonendemic pathogens related to donor travel history or country of origin. Lastly, the implications for recipient consent of expanded utilization of donors at increased risk of blood-borne viral disease transmission are considered.

Reactivation of Chagas disease among heart transplant recipients in the United States, 2012-2016

BACKGROUND

Heart transplantation has been shown to be a safe and effective intervention for progressive cardiomyopathy from chronic Chagas disease. However, in the presence of the immunosuppression required for heart transplantation, the likelihood of Chagas disease reactivation is significant. Reactivation may cause myocarditis resulting in allograft dysfunction and the rapid onset of congestive heart failure. Reactivation rates have been well documented in Latin America; however, there is a paucity of data regarding the risk in non-endemic countries.

METHODS

We present our experience with 31 patients with chronic Chagas disease who underwent orthotopic heart transplantation in the United States from 2012 to 2016. Patients were monitored following a standard schedule.

RESULTS

Of the 31 patients, 19 (61%) developed evidence of reactivation. Among the 19 patients, a majority (95%) were identified by laboratory monitoring using polymerase chain reaction testing. One patient was identified after the onset of clinical symptoms of reactivation. All subjects with evidence of reactivation were alive at follow-up (median: 60 weeks).

CONCLUSIONS

Transplant programs in the United States are encouraged to implement a monitoring program for heart transplant recipients with Chagas disease. Our experience using a preemptive approach of monitoring for Chagas disease reactivation was effective at identifying reactivation before symptoms developed.

Chagas Cardiomyopathy: An Update of Current Clinical Knowledge and Management: A Scientific Statement From the American Heart Association

Background:

Chagas disease, resulting from the protozoan Trypanosoma cruzi , is an important cause of heart failure, stroke, arrhythmia, and sudden death. Traditionally regarded as a tropical disease found only in Central America and South America, Chagas disease now affects at least 300 000 residents of the United States and is growing in prevalence in other traditionally nonendemic areas. Healthcare providers and health systems outside of Latin America need to be equipped to recognize, diagnose, and treat Chagas disease and to prevent further disease transmission.

Methods and Results:

The American Heart Association and the Inter-American Society of Cardiology commissioned this statement to increase global awareness among providers who may encounter patients with Chagas disease outside of traditionally endemic environments. In this document, we summarize the most updated information on diagnosis, screening, and treatment of T cruzi infection, focusing primarily on its cardiovascular aspects. This document also provides quick reference tables, highlighting salient considerations for a patient with suspected or confirmed Chagas disease.

Conclusions:

This statement provides a broad summary of current knowledge and practice in the diagnosis and management of Chagas cardiomyopathy. It is our intent that this document will serve to increase the recognition of Chagas cardiomyopathy in low-prevalence areas and to improve care for patients with Chagas heart disease around the world.

Molecular diagnosis of Trypanosoma cruzi

Chagas disease, caused by the kinetoplastid protozoan Trypanosoma cruzi, affects millions of people, most of them neglected populations. The different phases of the disease, the transmission mode and the high genetic variability of the parasite determine that molecular detection methods display different degree of success. Molecular diagnostic tests may be employed during epidemiological surveys of transmission, for early diagnosis of congenital transmission and acute infections due to oral transmission, transfusion or transplantation routes, reactivation due to immunosuppression and monitoring of treatment response in chronically infected patients receiving trypanocidal chemotherapy. This manuscript summarizes the most widely used molecular tools to detect T. cruzi infection in different epidemiological and clinical scenarios.

Solid Organ Transplant and Parasitic Diseases: A Review of the Clinical Cases in the Last Two Decades

The aim of this study was to evaluate the occurrence of parasitic infections in solid organ transplant (SOT) recipients. We conducted a systematic review of literature records on post-transplant parasitic infections, published from 1996 to 2016 and available on PubMed database, focusing only on parasitic infections acquired after SOT. The methods and findings of the present review have been presented based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist. From data published in the literature, the real burden of parasitic infections among SOT recipients cannot really be estimated. Nevertheless, publications on the matter are on the increase, probably due to more than one reason: (i) the increasing number of patients transplanted and then treated with immunosuppressive agents; (ii) the “population shift” resulting from immigration and travels to endemic areas, and (iii) the increased attention directed to diagnosis/notification/publication of cases. Considering parasitic infections as emerging and potentially serious in their evolution, additional strategies for the prevention, careful screening and follow-up, with a high level of awareness, identification, and pre-emptive therapy are needed in transplant recipients.

Chagas disease and liver transplantation: Experience in Argentina using real-time quantitative PCR for early detection and treatment

BACKGROUND

Chagas disease (CD) is an endemic zoonosis that occurs in Latin America and is caused by the parasite Trypanosoma cruzi. Early detection of T. cruzi in liver transplant recipients at risk may avoid complications from CD. The aim of this study was to examine the pre-operative evaluation and follow-up of CD after liver transplantation (LT) of patients at risk of CD using real-time quantitative polymerase chain reaction (qPCR) for T. cruzi.

METHODS

Between January 2009 and June 2016, 13 (12.7%) of 102 LTs performed in recipients at risk for CD without specific postoperative prophylaxis were prospectively evaluated using qPCR for T. cruzi. Four seronegative patients received livers from seropositive donors (R-/D+) and 9 seropositive recipients received livers from seronegative donors (R+/D-). A cohort of 89 patients without risk for CD during the same time period was analyzed as controls.

RESULTS

A positive qPCR for T. cruzi prior to LT was found in 2/9 (22.2%) seropositive recipients, and both achieved early response after therapy. The cumulative incidence of positive parasitemia after LT was higher in R+/D- than R-/D+ (37.7% vs 0%, P = .17). R+/D- transplant patients with positive qPCR achieved therapeutic response without manifestations of acute CD. LT outcomes at 1 year were similar in patients at risk of CD and in controls not at risk for CD.

CONCLUSION

A small proportion of T. cruzi-seropositive candidates presented positive parasitemia before LT. After LT, qPCR allowed detection of parasitemia leading to use of preemptive therapy in all R+/D- with T. cruzi replication. No cases of T. cruzi parasitemia occurred in R-/D+.

An autopsy-based study of Trypanosoma cruzi persistence in organs of chronic chagasic patients and its relevance for transplantation

BACKGROUND

Chagas' disease (CD) is caused by infection with the protozoan Trypanosoma cruzi. The disease can affect the heart and/or the gastrointestinal (GI) tract, but around 70% of infected individuals remain asymptomatic in the chronic form. Organ transplantation from T. cruzi-infected donors is often avoided because of the risk of disease transmission, previously reported after heart, kidney, or liver transplantation.

METHODS

We investigated by histology, immunohistochemistry, and polymerase chain reaction (PCR) the persistence of T. cruzi in samples of the heart, lung, liver, kidney, pancreas, adrenal gland, esophagus, and GI tract of 21 chronic chagasic patients.

RESULTS

Parasite persistence was detected in 12/21 (57.1%) heart samples, mainly by PCR-based assays. T. cruzi parasites were detected by histology and immunohistochemistry in smooth muscle cells of the central vein from 1/21 (4.8%) adrenal gland samples. No samples of the lung, liver, kidney, pancreas, esophagus, or GI tract were found to have parasites by histology, immunohistochemistry, or PCR.

CONCLUSIONS

We concluded that, aside from the heart, the other solid organs of T. cruzi-infected donors can be used for transplantation with a lot of caution. Such organs are not safe in the view of previous reports of CD transmission, but seem to present a low T. cruzi load compared to the heart.

Case Report: Successful Lung Transplantation from a Donor Seropositive for Trypanosoma cruzi Infection (Chagas Disease) to a Seronegative Recipient

The increasing shortage of organs for transplantation has prompted transplant programs to investigate the use of extended criteria donors, such as those with transmissible infectious diseases. Successful cases of organ transplantation (mostly kidney and liver) from Trypanosoma cruzi seropositive donors to seronegative recipients have been reported. We present a case of lung transplantation from a donor serologically positive for Chagas disease to a seronegative recipient, and provide a review of the literature. Left single lung transplantation was performed in a 44-year-old Spanish woman presenting with interstitial lung disease in February 2016. The deceased donor was a Colombian immigrant living in Spain who was serologically positive for Chagas disease. Oral administration of 5 mg/kg/day benznidazole divided in three doses for 60 days was given for specific Chagas disease prophylaxis after transplantation. Periodic follow-up with serological reverse transcription polymerase chain reaction to detect T. cruzi DNA were performed until 6 months after the end of treatment. All results were negative, indicating that transmission of T. cruzi had not occurred. In a review of the literature, two similar cases were identified in Argentina and the United States. In both cases T. cruzi infection was detected posttransplant in the recipients, after which they were treated with benznidazole. The course of the patient described herein confirms that lungs from donors with chronic T. cruzi infection can be used successfully as allografts, and that posttransplant prophylaxis with benznidazole may reduce the probability of transmission of T. cruzi to the recipient.

Analytical sensitivity and specificity of a loop-mediated isothermal amplification (LAMP) kit prototype for detection of Trypanosoma cruzi DNA in human blood samples

This study aimed to assess analytical parameters of a prototype LAMP kit that was designed for detection of Trypanosoma cruzi DNA in human blood. The prototype is based on the amplification of the highly repetitive satellite sequence of T.cruzi in microtubes containing dried reagents on the inside of the caps. The reaction is carried out at 65°C during 40 minutes. Calcein allows direct detection of amplified products with the naked eye. Inclusivity and selectivity were tested in purified DNA from Trypanosoma cruzi stocks belonging to the six discrete typing units (DTUs), in DNA from other protozoan parasites and in human DNA. Analytical sensitivity was estimated in serial dilutions of DNA samples from Sylvio X10 (Tc I) and CL Brener (Tc VI) stocks, as well as from EDTA-treated or heparinized blood samples spiked with known amounts of cultured epimastigotes (CL Brener). LAMP sensitivity was compared after DNA extraction using commercial fiberglass columns or after “Boil & Spin” rapid preparation. Moreover, the same DNA and EDTA-blood spiked samples were subjected to standardized qPCR based on the satellite DNA sequence for comparative purposes. A panel of peripheral blood specimens belonging to Chagas disease patients, including acute, congenital, chronic and reactivated cases (N = 23), as well as seronegative controls (N = 10) were evaluated by LAMP in comparison to qPCR. LAMP was able to amplify DNAs from T. cruzi stocks representative of the six DTUs, whereas it did not amplify DNAs from Leishmania sp, T. brucei sp, T. rangeli KPN+ and KPN-, P. falciparum and non-infected human DNA. Analytical sensitivity was 1x10^-2 fg/μL of both CL Brener and Sylvio X10 DNAs, whereas qPCR detected up to 1x 10⁻¹ fg/μL of CL Brener DNA and 1 fg/μl of Sylvio X10 DNA. LAMP detected 1x10^-2 parasite equivalents/mL in spiked EDTA blood and 1x10^-1 par.eq/mL in spiked heparinized blood using fiberglass columns for DNA extraction, whereas qPCR detected 1x10^-2 par.eq./mL in EDTA blood. Boil & Spin extraction allowed detection of 1x10^-2 par.eq /mL in spiked EDTA blood and 1 par.eq/ml in heparinized blood. LAMP was able to detect T.cruzi infection in peripheral blood samples collected from well-characterised seropositive patients, including acute, congenital, chronic and reactivated Chagas disease. To our knowledge, this is the first report of a prototype LAMP kit with appropriate analytical sensitivity for diagnosis of Chagas disease patients, and potentially useful for monitoring treatment response.

Trypanosoma cruzi, a parasite transmitted to humans from hematophagous insects, causes Chagas Disease, a Neglected Tropical Disease with public health impact, affecting 7 million people in Latin America. Although mainly related to low income populations inhabiting rural environments, migrations have conveyed Chagas Disease to urban areas of endemic and non-endemic countries. It often presents non-specific symptoms, and direct, low cost microscopy-based diagnosis only detects acute infections, missing a high proportion of cases. Serology is the “gold standard” diagnostic technique for chronic stages and needs the concordance of at least two different assays to confirm infection. In this context, we aimed to evaluate the analytical sensitivity and specificity of a prototype kit based on a novel and rapid molecular biology reaction, named Loop mediated isothermal amplification (LAMP), using standardized Real Time PCR as a comparator. To our knowledge, this is the first LAMP prototype kit with an analytical performance appropriate for human diagnosis of Chagas disease and potentially useful for monitoring treatment response. Its simple handling using basic laboratory devices will enable point-of-care diagnosis and screening for congenital infection at birth as well as early detection of acute infections due to oral contamination.

Molecular diagnostics for Chagas disease: up to date and novel methodologies

INTRODUCTION

Chagas disease is caused by the parasite Trypanosoma cruzi. It affects 7 million people, mainly in Latin America. Diagnosis is usually made serologically, but at some clinical scenarios serology cannot be used. Then, molecular detection is required for early detection of congenital transmission, treatment response follow up, and diagnosis of immune-suppression reactivation. However, present tests are technically demanding and require well-equipped laboratories which make them unfeasible in low-resources endemic regions. Areas covered: Available molecular tools for detection of T. cruzi DNA, paying particular attention to quantitative PCR protocols, and to the latest developments of user-friendly molecular diagnostic methodologies. Expert commentary: In the absence of appropriate biomarkers, molecular diagnosis is the only option for the assessment of treatment response. Besides, it is very useful for the early detection of acute infections, like congenital cases. Since current Chagas disease molecular tests are restricted to referential labs, research efforts must focus in the implementation of easy-to-use diagnostic tools in order to overcome the access to diagnosis gap.

Between a bug and a hard place: Trypanosoma cruzi genetic diversity and the clinical outcomes of Chagas disease

Over the last 30 years, concomitant with successful transnational disease control programs across Latin America, Chagas disease has expanded from a neglected, endemic parasitic infection of the rural poor to an urbanized chronic disease, and now a potentially emergent global health problem. Trypanosoma cruzi infection has a highly variable clinical course, ranging from complete absence of symptoms to severe and often fatal cardiovascular and/or gastrointestinal manifestations. To date, few correlates of clinical disease progression have been identified. Elucidating a putative role for T. cruzi strain diversity in Chagas disease pathogenesis is complicated by the scarcity of parasites in clinical specimens and the limitations of our contemporary genotyping techniques. This article systematically reviews the historical literature, given our current understanding of parasite genetic diversity, to evaluate the evidence for any association between T. cruzi genotype and chronic clinical outcome, risk of congenital transmission or reactivation and orally transmitted outbreaks.

Transplantation in the tropics: lessons on prevention and management of tropical infectious diseases

Tropical infectious diseases (IDs) remain a rare complication in transplant recipients even in tropical settings, but this topic has become increasingly important during the last decade due to multiple factors. Interestingly, non-tropical countries report most of the experiences with tropical diseases. The reported experience from non-endemic regions, however, does not always reflect the experience of endemic areas. Most of the guidelines and recommendations in the literature may not be applicable in tropical settings due to logistical difficulties, cost, and lack of proven benefit. In addition, certain post-transplant prevention measures, as prophylaxis and reducing exposure risk, are not feasible. Nonetheless, risk assessment and post-transplant management of tropical IDs in tropical areas should not be neglected, and clinicians need to have a higher clinical awareness for tropical ID occurring in this population. Herein, we review the more significant tropical ID in transplant patients, focusing on relevant experience reported by tropical settings.

Multiplex Real-Time PCR Assay Using TaqMan Probes for the Identification of Trypanosoma cruzi DTUs in Biological and Clinical Samples

BACKGROUND

Trypanosoma cruzi has been classified into six Discrete Typing Units (DTUs), designated as TcI-TcVI. In order to effectively use this standardized nomenclature, a reproducible genotyping strategy is imperative. Several typing schemes have been developed with variable levels of complexity, selectivity and analytical sensitivity. Most of them can be only applied to cultured stocks. In this context, we aimed to develop a multiplex Real-Time PCR method to identify the six T. cruzi DTUs using TaqMan probes (MTq-PCR).

METHODS/PRINCIPAL FINDINGS

The MTq-PCR has been evaluated in 39 cultured stocks and 307 biological samples from vectors, reservoirs and patients from different geographical regions and transmission cycles in comparison with a multi-locus conventional PCR algorithm. The MTq-PCR was inclusive for laboratory stocks and natural isolates and sensitive for direct typing of different biological samples from vectors, reservoirs and patients with acute, congenital infection or Chagas reactivation. The first round SL-IR MTq-PCR detected 1 fg DNA/reaction tube of TcI, TcII and TcIII and 1 pg DNA/reaction tube of TcIV, TcV and TcVI reference strains. The MTq-PCR was able to characterize DTUs in 83% of triatomine and 96% of reservoir samples that had been typed by conventional PCR methods. Regarding clinical samples, 100% of those derived from acute infected patients, 62.5% from congenitally infected children and 50% from patients with clinical reactivation could be genotyped. Sensitivity for direct typing of blood samples from chronic Chagas disease patients (32.8% from asymptomatic and 22.2% from symptomatic patients) and mixed infections was lower than that of the conventional PCR algorithm.

CONCLUSIONS/SIGNIFICANCE

Typing is resolved after a single or a second round of Real-Time PCR, depending on the DTU. This format reduces carryover contamination and is amenable to quantification, automation and kit production.

Trypanosoma cruzi infection in a Spanish liver transplant recipient

The shortage of suitable organ donors for transplantation has stimulated the use of organs from donors with transmissible infections such as Chagas disease in noninfected recipients. A case is described of liver transplantation from an anti-Trypanosoma cruzi-positive donor to a noninfected recipient who showed favorable evolution despite not having undergone preemptive therapy.

Chagas disease in the immunosuppressed patient

This review addresses relevant aspects of Chagas disease in the immunocompromised host. Chagas disease--one of the world's most neglected diseases-has become a global public health concern. Novel transmission modalities, such as organ transplantation, evidence of parasite persistence in chronically infected individuals--with the potential for reactivation under immunosuppression--and the prolonged survival of immunosuppressed patients call for an appraisal of the disease in this particular setting. The management and outcome of solid organ transplantation in the infected recipient with special focus on heart transplantation is addressed. The guidelines for management and the outcome of the recipients of organs from infected donors are discussed, and comments on haematopoietic stem cell transplantation are included. Finally, Chagas disease in other situations of impairment of the immune system, such as HIV/AIDS and autoimmune diseases, are considered. Immunosuppression has become an increasingly frequent condition that might modify the natural history of Trypanosoma cruzi infection. A number of strategies are available for Chagas disease management in the immunosuppressed patient. First, according to recent recommendations from the health authorities in Argentina, most infected patients would benefit from being treated at diagnosis. This has not been validated for patients with different immunosuppressive disorders. A different strategy would involve treating only patients with documented reactivation (either parasitaemia or clinical manifestations). These different approaches are discussed. To reach a diagnosis of parasitaemia, monitoring is essential, either with conventional methods or with molecular techniques that are not yet available in all centres. Collaborative studies are needed to improve the level of evidence, which will allow for better guidelines.

Diagnosis of Parasitic Infections

Methods for the diagnosis of parasitic infections have stagnated in the past three decades. Labor-intensive methods such as microscopy still remain the mainstay of several diagnostic laboratories. There is a need for more rapid tests that do not sacrifice sensitivity and that can be used in both clinical settings as well as in poor resource field settings. The fields of diagnostic medical parasitology, treatment, and vaccines are undergoing dramatic change. In recent years, there has been tremendous effort to focus research on the development of newer diagnostic methods focusing on serological, molecular, and proteomic approaches. This article examines the various diagnostic tools that are being used in clinical laboratories, optimized in reference laboratories, and employed in mass screening programs.