Strongyloides stercoralis hyperinfection after allogeneic stem cell transplantation

Severe strongyloidiasis: a systematic review and meta-analysis of 339 cases

Strongyloidiasis is a parasitosis representing a significant public health problem in tropical countries. It is often asymptomatic in immunocompetent individuals but its mortality rate increases to approximately 87% in severe forms of the disease. We conducted a systematic review, including case reports and case series, of Strongyloides hyperinfection and dissemination from 1998 to 2020 searching PubMed, EBSCO and SciELO. Cases that met the inclusion criteria of the Preferred Reported Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist were analysed. Statistical analysis was performed using Fisher's exact test and Student's t-test and a Bonferroni correction for all the significant values. A total of 339 cases were included in this review. The mortality rate was 44.83%. The presence of infectious complications, septic shock and a lack of treatment were risk factors for a fatal outcome. Eosinophilia and ivermectin treatment were associated with an improved outcome.

A comprehensive review of Strongyloides stercoralis infection after solid organ and hematopoietic stem cell transplantation

BACKGROUND

We reviewed the scientific literature to gain insight on the epidemiology and outcome of Strongyloides stercoralis infections after transplantation.

METHODS

CINAHL, PUBMED, and OVID/MEDLINE were reviewed from inception through March 31, 2022 using key words Strongyloides and transplantation.

RESULTS

Our review identified 108 episodes of Strongyloides infection among 91 solid organ transplant (SOT) and 15 hematopoietic cell transplant (HCT) recipients. Median time to infection was 10.8 (range, .14-417) and 8.8 (range, 0-208) weeks after SOT and HCT, respectively. Gastrointestinal symptoms were frequent (86/108 [79.6%]), while skin rash (22/108 [20.3%]) and fever (31/103 [30%]) were less common. Peripheral eosinophilia was observed in half of patients (41/77 [53.2%]). Bacteremia (31/59 [52.5%]) was frequently due to Gram-negative organisms (24/31 [77.4%]). Abnormal chest radiologic findings were reported in half (56/108 [51.9%]). The majority had hyperinfection syndrome (97/108 [89.8%]) while disseminated strongyloidiasis was less common (11/108 [10.2%]). Thirty-two cases were categorized as donor-derived infection (DDI), with donors (23/24 [95.8%]) who had traveled to or lived in endemic areas. Median time to DDI was 8 weeks (range .5-34.3 weeks) after transplantation. Treatment consisted of ivermectin (n = 26), a benzimidazole (n = 27), or both drugs (n = 28). There was high all-cause mortality (48/107, 44.9%) and a high Strongyloides-attributable mortality (32/49, 65.3%).

CONCLUSIONS

Strongyloidiasis should be strongly considered among recipients with epidemiologic risk factors for infection, even in the absence of eosinophilia or rash. A policy that provides guidance on pro-active screening is needed, to ensure preventive measures are provided to recipients at increased risk.

Strongyloides stercoralis prevalence in solid-organ and haematopoietic stem cell transplant candidates and recipients: a systematic review and meta-analysis protocol

INTRODUCTION

Strongyloides stercoralis is an intestinal helminth ubiquitous in tropical and subtropical regions worldwide. It persists in the human host for a lifetime as a result of autoinfection and if undetected and untreated, can lead to increased morbidity and high mortality in immunocompromised individuals such as the transplant population. Transplant patients, including solid-organ and haematopoietic stem cell transplants (SOT and HSCT, respectively), are at a high risk of hyperinfection and disseminated strongyloidiasis. Unfortunately screening is often not systematically performed. Prevalence estimates of Strongyloides in this high-risk population is not well studied. Through this systematic review, we aim to summarise the descriptive evidence on Strongyloides prevalence in SOT and HSCT patients, including diagnostic and screening practices alongside the cases of hyperinfection, disseminated strongyloidiasis and the mortality rate in this population.

METHODS AND ANALYSES

Through the use of various online library databases, we will conduct a systematic review including relevant literature on the prevalence of Strongyloides in SOT and HSCT patients as well as studies assessing hyperinfection and disseminated strongyloidiasis in this patient population. The Population, Intervention, Comparison, Outcome and Study Design strategy and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines will be used to determine a final subset of studies for analysis. Quality assessment for case series and case reports will be determined by a modified quality assessment tool developed by the National Heart, Lung, and Blood Institute (NIH), and the CARE guidelines, respectively. We will provide a narrative synthesis of the findings pertaining to the primary and secondary outcomes of interest (prevalence of Strongyloides and mortality rate in transplant population, respectively) alongside the associated 95% CI. Estimates from individual studies will be pooled using a random effects model.

ETHICS AND DISSEMINATION

This systematic review does not require formal ethical approval since no primary data will be collected. Findings will be disseminated through a peer-reviewed publication and relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42021269305.

Describing universal Strongyloides serologic screening among pediatric intestinal and liver transplant recipients

BACKGROUND

Strongyloides spp hyperinfections are a worldwide phenomenon that proves fatal for solid organ transplant recipients. Screening protocols to guide prophylaxis management vary institution to institution from universal to epidemiology driven. Our institution initiated a universal screening protocol regardless of travel history and exposure to ensure no cases were missed.

METHODS

In this study, we describe the outcomes of three Strongyloides sero-positive children whom underwent intestinal or liver transplantation and the experience of universal screening at a tertiary care county hospital in South Florida.

RESULTS

Among the 66 intestine and liver pediatric transplant recipients who were screened for Strongyloides antibodies, only three were identified to be sero-positive via the screening mechanism. Two of three had significant epidemiology risk factors. None of the patients reviewed were found to have developed hyperinfection. However, reflecting on the experience represented by our series of pediatric patients, the risk of any complication related to Strongyloides status appears low. Even among this South Florida population whom come from or travel to endemic regions are in contact with sero-positive individuals, very few illustrate sero-positivity.

CONCLUSION

While institutions continue to analyze the cost-benefit of universal testing vs. universal prophylaxis vs. targeted screening, the decision must encompass the patient population, rolling cumulative incidence, and morbidity and mortality related to this disease.

Syndrome of Inappropriate Anti-Diuretic Hormone Secretion Secondary to Strongyloides stercoralis Infection in an Allogeneic Stem Cell Transplant Patient: A Case Report and Literature Review

Syndrome of inappropriate anti-diuretic hormone (SIADH) has been reported to be associated with systemic Strongyloides stercoralis. Here, we report a case of a stem cell transplant (SCT) recipient who developed severe SIADH secondary to systemic S Stercoralis. The SIADH resolved quickly after treating the systemic S Stercoralis with ivermectin. A systematic review of the literature was performed by PubMed, Scopus, and Cochrane database search. Only eight cases of S Stercoralis in allogeneic SCT recipients have been previously reported. To our knowledge, ours is the first reported case of SIADH secondary to S Stercoralis infection in an allogeneic SCT recipient. Prior to transplantation, even if asymptomatic, patients from endemic regions should be screened with strongyloides immunoglobulin (Ig)G serology. Pretransplantation eosinophilia should be evaluated by screening multiple stool samples for ova and parasites. Transplant candidates with positive serology or stool tests can be treated pretransplantation to eradicate infection. Patients at risk for S Stercoralis who develop nonspecific gastrointestinal complaints, rash, pulmonary infiltrates, or gram-negative bacteremia or meningitis may have S Stercoralis hyperinfection syndrome. Our case indicates that the development of SIADH may be an additional clue to this diagnosis. Appropriate diagnostic studies, including repeat stool and other body fluid sampling, should be expedited and ivermectin therapy initiated rapidly to prevent significant morbidity and mortality.

Allogeneic hematopoietic stem cell transplant recipients and parasitic diseases: A review of the literature of clinical cases and perspectives to screen and follow-up active and latent chronic infections

BACKGROUND

Allogeneic hematopoietic stem cell transplant (HSCT) recipients are at substantial risk for a variety of infections depending upon numerous factors, such as degree of immunosuppression, host factors, and period after transplantation. Bacterial, fungal, viral, as well as parasitic infections can occur with high morbidity and mortality.

OBJECTIVES

The aim of this study was to evaluate the magnitude of the occurrence of parasitic infections in allogeneic HSCT recipients. Modalities of transmission, methods of diagnosis, treatment, donor and recipient pre-transplant screening and prevention measures of the most serious parasitic infections have also been discussed.

MATERIALS AND METHODS

We systematically reviewed literature records on post-transplant (allogeneic HSCT) parasitic infections, identified through PubMed database searching, using no language or time restrictions. Search was concluded on December 31, 2015. In the present review, we only discussed post-transplant parasitic infections in allogeneic HSCT. Only exclusion criteria were absence of sufficient information on the transmission of parasitic infection to the recipient. Autologous HSCT recipients have not been included because of the absence of a proper allogeneic transplantation even in presence of blood or blood product transfusions. The methods and findings of the present review have been reported based on the preferred reporting items for systematic reviews and meta-analysis checklist (PRISMA).

RESULTS

Regarding allogeneic HSCT recipients, from data published in the literature the real burden of parasitic infections cannot be really estimated. Nevertheless, a positive trend on publication number exists, probably because of 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 increasing of attention for diagnosis/notification/publication of cases.

CONCLUSIONS

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 suspicion, identification, and preemptive therapy are necessary in transplant recipients.

PERSPECTIVES

The Authors' viewpoint in the perspective to screen and follow-up active and latent chronic parasitosis in stem cells donors and recipients: a proposal for a flow chart.

Molecular diagnosis in clinical parasitology: When and why?

Microscopic detection and morphological identification of parasites from clinical specimens are the gold standards for the laboratory diagnosis of parasitic infections. The limitations of such diagnostic assays include insufficient sensitivity and operator dependence. Immunoassays for parasitic antigens are not available for most parasitic infections and have not significantly improved the sensitivity of laboratory detection. Advances in molecular detection by nucleic acid amplification may improve the detection in asymptomatic infections with low parasitic burden. Rapidly accumulating genomic data on parasites allow the design of polymerase chain reaction (PCR) primers directed towards multi-copy gene targets, such as the ribosomal and mitochondrial genes, which further improve the sensitivity. Parasitic cell or its free circulating parasitic DNA can be shed from parasites into blood and excreta which may allow its detection without the whole parasite being present within the portion of clinical sample used for DNA extraction. Multiplex nucleic acid amplification technology allows the simultaneous detection of many parasitic species within a single clinical specimen. In addition to improved sensitivity, nucleic acid amplification with sequencing can help to differentiate different parasitic species at different stages with similar morphology, detect and speciate parasites from fixed histopathological sections and identify anti-parasitic drug resistance. The use of consensus primer and PCR sequencing may even help to identify novel parasitic species. The key limitation of molecular detection is the technological expertise and expense which are usually lacking in the field setting at highly endemic areas. However, such tests can be useful for screening important parasitic infections in asymptomatic patients, donors or recipients coming from endemic areas in the settings of transfusion service or tertiary institutions with transplantation service. Such tests can also be used for monitoring these recipients or highly immunosuppressed patients, so that early preemptive treatment can be given for reactivated parasitic infections while the parasitic burden is still low.

Fatal strongyloides hyperinfection complicating a gram-negative sepsis after allogeneic stem cell transplantation: a case report and review of the literature

Strongyloides stercoralis is an intestinal nematode that causes strongyloidiasis, which affects 30 to 100 million people worldwide. Risk factors for hyperinfection and disseminated disease include immunosuppressive drug therapy, human T-lymphotropic virus-1 (HTLV-1) infection, solid organ and bone marrow transplantation, hematologic malignant diseases, hypogammaglobulinemia, and severe malnutrition and associated conditions. The diagnosis can be difficult because a single stool examination fails to detect larvae in up to 70% of the cases, and the symptoms are nonspecific. Although eosinophilia is a common finding in patients with chronic Strongyloides infection, it is an unreliable predictor of hyperinfection. Furthermore, the lack of eosinophilia while receiving immunosuppressive therapy cannot reliably exclude the underlying chronic Strongyloides infection. We report here a fatal Strongyloides hyperinfection in a patient receiving allogeneic stem cell transplantation; risk factors and outcome in this clinical setting are discussed.

Severe strongyloidiasis: a systematic review of case reports

BACKGROUND

Strongyloidiasis is commonly a clinically unapparent, chronic infection, but immuno suppressed subjects can develop fatal disease. We carried out a review of literature on hyperinfection syndrome (HS) and disseminated strongyloidiasis (DS), in order to describe the most challenging aspects of severe strongyloidiasis.

METHODS

We conducted a structured search using PubMed to collect case reports and short case series on HS/DS published from 1991 to 2011. We restricted search to papers in English, Spanish, Italian and French. Case reports were classified as HS/DS according to given definitions.

RESULTS

Records screened were 821, and 311 were excluded through titles and abstract evaluation. Of 510 full-text articles assessed for eligibility, 213 were included in qualitative analysis. As some of them were short case series, eventually the number of cases analyzed was 244.Steroids represented the main trigger predisposing to HS and DS (67% cases): they were mostly administered to treat underlying conditions (e.g. lymphomas, rheumatic diseases). However, sometimes steroids were empirically prescribed to treat signs and symptoms caused by unsuspected/unrecognized strongyloidiasis. Diagnosis was obtained by microscopy examination in 100% cases, while serology was done in a few cases (6.5%). Only in 3/29 cases of solid organ/bone marrow transplantation there is mention of pre-transplant serological screening. Therapeutic regimens were different in terms of drugs selection and combination, administration route and duration. Similar fatality rate was observed between patients with DS (68.5%) and HS (60%).

CONCLUSIONS

Proper screening (which must include serology) is mandatory in high - risk patients, for instance candidates to immunosuppressive medications, currently or previously living in endemic countries. In some cases, presumptive treatment might be justified. Ivermectin is the gold standard for treatment, although the optimal dosage is not clearly defined in case of HS/DS.

Hyperinfection with Strongyloides stercoralis

Strongyloidiasis is caused by Strongyloides stercoralis, which commonly produces gastrointestinal problems. If immune systems are compromised, the nematode larvae may spread and produce Strongyloides hyperinfection. Diagnosis of strongyloidiasis is based on the observation of larvae in coproparasitological studies. We present a case of a 49-year-oldman, VIH, who developed Strongyloides hyperinfection, diagnosed postmortem. Our patient reached the dissemination stage, which resulted in severe damage to the stomach and intestine, perforation of the intestinal wall, as well as sepsis due to the dissemination of bacteria. The diagnosis is difficult because of the low larvae excretion in stools. It is usually performed by the microscopic examination of fresh and fixed enriched stool samples. Serology was reported to be useful for screening and follow-up after treatment. This case reaffirms that HIV immunosuppression favours the dissemination of S stercoralis larvae. Thus, a search for intestinal parasites should be considered in similar cases.

Epidemiological aspects of strongyloidiasis in Brazil

The objective of this review was to outline an epidemiological profile of Strongyloides stercoralis by parasitological and serological diagnosis in inhabitants, and to associate this profile with different immunosupression situations, in Brazil, over 20 years (1990-2009). The occurrence of S. stercoralis using parasitological methods was 5·5%, being 4·8% in rural and 5·0% in urban areas, characterizing the country as hyperendemic. There was a diversity of techniques used as a diagnostic tool and only 39·1% of the studies presented results based on at least 1 specific method. The occurrence increased with age, being 12·1%, for those over 60 that suggests an epidemiological condition of concern for the elderly population. Of the seroepidemiological studies in the general population the mean positivity in serum samples was 21·7% and 29·2%, using an immunofluorescence antibody test and enzyme-linked immunosorbent assay (ELISA), respectively. The occurrence of strongyloidiasis in immunosuppressed individuals was 11·8% by parasitological methods and 19·5% using immunological methods. Considering that Brazil is a tropical country and that the character of chronicity and autoinfection of the parasite that can result in severe forms of hyperinfection or dissemination makes strongyloidiasis an important medically and socially neglected problem.

Strongyloidiasis in transplant patients

Strongyloides stercoralis is an intestinal nematode that can persist in the human host for decades after the initial infection and can progress to fulminant hyperinfection syndrome in immunocompromised hosts. We describe a patient who died of Strongyloides hyperinfection syndrome 2 months after orthotopic heart transplantation and discuss approaches to prevention, diagnosis, and treatment. Current practice guidelines recommend screening for and treatment of Strongyloides infection before transplantation, but physicians in the United States often miss opportunities to identify patients with chronic strongyloidiasis. Screening tests have limitations, and clinical suspicion remains an important component of the evaluation before transplantation. After immunocompromised patients develop hyperinfection syndrome, diagnosis is often delayed and mortality is high, so emphasis must be placed on screening and treatment before transplantation. We review current strategies for prevention, diagnosis, and treatment of chronic intestinal strongyloidiasis in patients who will undergo transplantation and discuss the clinical features and management of Strongyloides hyperinfection syndrome in transplant recipients.