Strongyloidiasis: A Neglected Tropical Disease

Evaluation of an Innovative Rapid Diagnostic Test for Human Strongyloidiasis to Detect Specific IgG Antibody in Whole-Blood Samples

Human strongyloidiasis is an important intestinal parasitic disease that affects public health globally and is transmitted through contact with infective larvae on contaminated soil. Immunocompromised hosts can experience hyperinfection, which can lead to fatal systemic strongyloidiasis. Here, an innovative point-of-care (POC) test kit, the strongyloidiasis immunochromatographic blood test (the NIE-SsIR whole-blood ICT) kit is described. The kit was used to detect anti-Strongyloides IgG antibody in whole-blood samples (WBSs) instead of serum to diagnose strongyloidiasis. The kit is based on a mixture of two recombinant Strongyloides stercoralis protein antigens (NIE and SsIR) and colloidal-gold-labeled conjugates of anti-human IgG antibody to evaluate diagnostic values with simulated and fresh anticoagulated WBSs. The NIE-SsIR whole-blood ICT kit showed potentially high diagnostic values with simulated WBSs, obtained by spiking patients' sera with red blood cells. The sensitivity, specificity, and positive and negative predictive values were 93.0%, 93.7%, 88.6%, and 96.2%, respectively, at the prevalence of disease simulated under the laboratory conditions of 34.5%. In addition, 18 of 20 fresh anticoagulated WBSs from strongyloidiasis cases were positive, and all 15 WBSs from healthy volunteers were negative. The NIE-SsIR whole-blood ICT kit is a simple and convenient POC testing tool and can possibly be used with fingerstick blood samples, thereby not requiring the drawing of venous blood and separation of the serum. The NIE-SsIR whole-blood ICT kit can assist clinical diagnosis in remote areas and field settings without sophisticated equipment.

Strongyloides stercoralis infection in a DLBCL patient treated with rituximab and BTK inhibitor: A case report and literature review

RATIONALE

Diffuse large B-cell lymphoma (DLBCL) is a common subtype of non-Hodgkin's lymphoma characterized by high malignancy, rapid onset and aggressive clinical behavior. The disease exhibits considerable heterogeneity, which influences clinical and immunophenotypic characteristics, which in turn affect treatment outcomes and prognosis. Recently, targeted therapies have been introduced, offering improved therapeutic efficacy but with risks such as immunosuppression and opportunistic infections.

PATIENT CONCERNS

We report a case of a patient diagnosed with DLBCL who experienced immunosuppression as a result of treatment with rituximab and a Bruton's tyrosine kinase inhibitor, which subsequently led to Strongyloides stercoralis infection.

DIAGNOSES

The patient was diagnosed with S. stercoralis infection, confirmed by appropriate diagnostic tests after the onset of clinical symptoms suggestive of parasitic infection.

INTERVENTIONS

The patient was treated with a combination of rituximab and a Bruton's tyrosine kinase inhibitor as part of her DLBCL therapy. Antiparasitic treatment was started after diagnosis of S. stercoralis infection.

OUTCOMES

The patient's infection was successfully managed with antiparasitic therapy, although the case highlights the need for vigilant monitoring of immunosuppressive therapy in patients with DLBCL due to the risk of opportunistic infections.

LESSONS

This case highlights the potential complications of targeted therapies in DLBCL, particularly the risk of opportunistic infections such as S. stercoralis. It highlights the importance of careful patient monitoring and prompt intervention to effectively manage such infections.

Diagnostic value of urinary and serum IgG antibodies in evaluating drug treatment response in strongyloidiasis assessed by fecal examination and digital droplet PCR

Detection of Strogyloides-specific IgG antibodies in urine and serum has been used in diagnostic and epidemiological studies on strongyloidiasis. However, the usefulness of these assays in assessing responses to anthelmintic treatment is unclear. Thus, we evaluated the diagnostic performance and temporal profiles of Strongyloides-specific IgG antibodies in a cohort of participants at baseline and post-treatment. The participants were prospectively screened for baseline parasitic infections by fecal examination [agar plate culture technique (APCT) and formalin-ethyl acetate concentration technique (FECT)] and digital droplet polymerase reaction (ddPCR) for Strongyloides stercoralis. At each sampling point, Strongyloides-specific IgG in urine and serum were measured by an in-house S. ratti-based enzyme-linked immunosorbent assay (ELISA). At baseline, 169 of 351 participants (48.1%) had S. stercoralis infection by the combined fecal examination and ddPCR. The diagnostic sensitivities of IgG in urine and serum were 91.1% and 88.2%, respectively. The participants were given treatment with a single oral dose of ivermectin (IVM, 200 μg/kg) and were followed up by fecal and immunological diagnosis at 3 to 18 months post-treatment. The cure rate of IVM treatment evaluated by APCT and ddPCR was 88.3% at three months post-treatment. The profiles of IgG in urine in the curative treatment group showed a significant trend of decline with time post-treatment (Kruskal-Wallis test = 113.4-212.6, p value < 0.0001) and the lowest levels were seen 12 months post-treatment. The treatment response (> 50% reduction in urinary IgG antibody units) was 100%, and conversion from positive to negative results was 65.4%. The treatment response and conversion to negative assessed by serum IgG-ELISA were similar to those by urine IgG-ELISA. The results from this long-term diagnostic study highlight the utility of urinary IgG and serum IgG for screening and monitoring treatment outcomes in strongyloidiasis.

A scoping review of transmission models for soil-transmitted helminth infections to underpin the development of a transmission model for Strongyloides stercoralis

Soil-transmitted helminth (STH) infections afflict people worldwide, especially in tropical and subtropical regions. Strongyloides stercoralis is distinctive from other STH nematodes by its complex life cycle features of autoinfection, parthenogenesis, and environmental reproduction. This scoping review aims to identify the structures, features, and techniques employed in existing STH models, emphasizing their potential application in describing S. stercoralis infection dynamics. A comprehensive search was conducted in the Medline, Embase, and Scopus databases for studies published until 14 June 2024. A total of 47 studies presenting a new model or novel adaptation of an existing model to human STH infection transmission were identified: only one described S. stercoralis transmission in humans. The identified models were predominantly deterministic and focused on the dynamics of mean worm load within hosts and the infectiousness of the environmental reservoir. One model addressed transmission in multi-host scenarios, as not all STH transmission cycles involve multiple hosts. Models were frequently used to simulate the effectiveness of mass drug administration, including drug efficacy and treatment coverage, while water, sanitation, and hygiene (WASH), health education, and vaccination were less explored. Given the limitation of individual-level data, compartmental models may be a reasonable starting point for S. stercoralis transmission. For a comprehensive understanding, incorporating parasite life cycle features into the model, exploring multi-host dynamics, including a diverse range of host heterogeneities, and assessing the impact of climatic factors like rainfall and land surface temperature on parasite survival in the environment may be beneficial, especially in settings where their importance is notable.

More Than Just Stool: Hypereosinophilic Syndrome Presenting as Persistent Diarrhea in a Patient With Ulcerative Colitis

We highlight a case of non-infectious diarrhea that progressed despite supportive care, prompting further workup. A 50-year-old man presented with 1 week of voluminous diarrhea, nausea, emesis, and abdominal pain. His history included ulcerative colitis, primary sclerosing cholangitis, Clostridioides difficile treated via total colectomy with ileoanal pouch, treated disseminated Mycobacterium avium complex, and international travel. On physical exam he had normal vital signs, diffuse abdominal tenderness without peritoneal signs, and a rash. Lab work revealed leukocytosis with eosinophilia, hyponatremia, and elevated creatinine. Lactate, inflammatory markers, stool studies, and computed tomography of his abdomen were normal. Tissue biopsies of the duodenum, ileum, and rectal pouch collected during colonoscopy and push enteroscopy revealed prominent mucosal eosinophilia, confirming the diagnosis of hypereosinophilic syndrome (HES). Treatment with steroids led to significant improvement in all symptoms and blood eosinophilia. This case highlights the importance of aggressive workup of diarrhea with peripheral eosinophilia, especially in patients with ulcerative colitis: waiting 6 months to confirm the diagnosis via blood work would delay treatment. Notably, infection with Strongyloides stercoralis was ruled out in this case prior to treatment. This is an important step in the workup and management of HES to prevent progression of Strongyloidiasis.

A 5-year single-center review of Strongyloides seropositivity in kidney transplant candidates in Central Texas

Introduction

Strongyloides stercoralis is a soil-transmitted helminth that can lead to life-threatening hyperinfection in transplant recipients. Targeted screening based on social history alone may preclude a large proportion of seropositive patients. Our institution implemented universal screening for kidney transplant candidates. This study aimed to identify the prevalence and identify risk factors of transplant candidates.

Methods

This was a retrospective chart review of kidney transplant candidates who were Strongyloides seropositive using the Strongyloides IgG enzyme-linked immunosorbent assay (ELISA) test. An equivocal Strongyloides serology was defined as 1.0 to 1.1 IV, a positive test as >1.1 IV, and a negative test as <1.0 IV.

Results

A total of 1653 patients underwent screening for Strongyloides, and 121 (7.3%) tested positive. Forty-seven patients (38.8%) who tested positive had no reported travel history to endemic areas, and 86% of patients originated from the United States. Forty-six patients (97.9%) who received a kidney transplant received treatment with ivermectin, and none developed disseminated disease or hyperinfection.

Conclusions

Among kidney transplant candidates screened for Strongyloides, 7.3% were seropositive and many reported no travel history to endemic areas, which highlights the significant prevalence of this parasite in Central Texas. Universal screening at our institution identified a substantial number of seropositive patients who might have otherwise been missed.

Residual gastritis associated with Strongyloides stercoralis infection: A case report

RATIONALE

Strongyloides stercoralis, a rare human intestinal parasite, poses a significant health risk, capable of causing lifelong infection and even mortality due to its atypical manifestation of symptoms. In this case report, we reported a case of a patient diagnosed with S. stercoralis infection of the residual stomach and meticulously detail its treatment process, offering valuable insights and a reference point for clinicians.

PATIENT CONCERNS

we report a case of infection caused by S. stercoralis after subtotal gastrectomy (Billroth type II) in a 47-year-old middle-aged man. It presents with recurrent nausea and vomiting, accompanied by intermittent food residue vomiting and constipation.

DIAGNOSES

Upon endoscopic examination, we observed mucosal swelling and erosion in the anastomosis and output ring of stomach, while pathological analysis confirmed the presence of Strongyloides stercoralis eggs. Subsequently, the administration of albendazole for anti-infection treatment proved to be effective, thereby reinforcing the diagnosis of S. stercoralis infection.

INTERVENSIONS

The patient underwent aggressive management including fasting, fluid replacement, anti-infection therapy, albumin supplementation, and albendazole treatment at a dose of 300 mg/kg/day for 3 days to eliminate the parasite.

OUTCOMES

After treatment, the patient's symptoms of nausea, vomiting, and constipation were alleviated and returned to normal upon discharge. Over the subsequent 3 years, the patient reported no instances of vomiting and experienced a recovery of digestive function compared to their discharge status.

LESSONS

S. stercoralis infection is relatively rare in the remnant stomach, endoscopic and pathological examination may be one of the important methods to diagnose S. stercoralis infection, and it is effective to treat albendazole according to the course of treatment.

Probiotics as a strategy for addressing helminth infections in low-income countries: Working smarter rather than richer

Helminth infections, which affect approximately 1.5 billion individuals worldwide (mainly children), are common in low- and middle-income tropical countries and can lead to various diseases. One crucial factor affecting the occurrence of these diseases is the reduced diversity of the gut microbiome due to antibiotic use. This reduced diversity compromises immune health in hosts and alters host gene expression through epigenetic mechanisms. Helminth infections may produce complex biochemical signatures that could serve as therapeutic targets. Such therapies include next-generation probiotics, live biotherapeutic products, and biochemical drug approaches. Probiotics can bind ferric hydroxide, reducing the iron that is available to opportunistic microorganisms. They also produce short-chain fatty acids associated with immune response modulation, oral tolerance facilitation, and inflammation reduction. In this review, we examine the potential link between these effects and epigenetic changes in immune response-related genes by analyzing methyltransferase-related genes within probiotic strains discussed in the literature. The identified genes were only correlated with methylation in bacterial genes. Various metabolic interactions among hosts, helminth parasites, and intestinal microbiomes can impact the immune system, potentially aiding or hindering worm expulsion through chemical signaling. Implementing a comprehensive strategy using probiotics may reduce the impact of drug-resistant helminth strains.

High prevalence of anti-Strongyloides antibody in SARS-CoV-2-infected human sera in a Thai hospital: Rapid serological screening

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can stimulate a systemic inflammatory response with severe lung involvement, multisystem dysfunction, and death in some cases. Immunosuppressive treatments have been proposed for management of COVID-19 patients, but these bring the risk of flare-up of pre-existing infections. Strongyloidiasis can become severe or fatal in immunocompromised individuals. This cross-sectional study determined the prevalence of anti-Strongyloides IgG antibody in sera collected from SARS-CoV-2 infected persons in a tertiary-care Thai hospital from January 2021 to January 2022. The survey was conducted using a rapid immunochromatographic test (ICT) kit based on a recombinant antigen of Strongyloides stercoralis known to be IgG-immunoreactive. High prevalence of anti-Strongyloides IgG antibody was found. Out of 297 SARS-CoV-2-infected patients 117 (39.4 %, 95 % CI 33.8-45.2 %) were positive for S. stercoralis according to the ICT kit. In areas where strongyloidiasis is endemic, we suggest using this point-of-care ICT kit for routine rapid screening in seriously ill COVID-19 patients who will be subjected to immunosuppressive treatment. Prompt anthelminthic treatment should be administered to prevent serious systemic strongyloidiasis in at-risk patients.

Comparison of parasitological methods for the identification of soil-transmitted helminths, including Strongyloides stercoralis, in a regional reference laboratory in northwestern Argentina: An observational study

Soil-transmitted helminths (STH) are a significant public health problem in impoverished communities of tropical and subtropical areas. Improved diagnostic methods are crucial for Neglected Tropical Diseases programs, particularly for S. stercoralis, as traditional methods are inadequate. Thus, it is important to identify the most accurate and efficient methods for the diagnosis of STH. We performed a retrospective study analyzing laboratory data at the Instituto de Investigaciones de Enfermedades Tropicales from 2010 to 2019. The study included data from outpatients referred for stool analysis and public health interventions from urban and rural communities in northern Salta province, Argentina. Samples were included in this analysis if processed through sedimentation/concentration, Baermann, Harada-Mori and McMaster's, with a subgroup that also included Agar plate culture method (APC). Sensitivity was calculated against a composite reference standard. Of the 5625 samples collected, 944 qualified for this analysis, with a prevalence of 11.14% for A. lumbricoides, 8.16% for hookworm, 1.38% for T. trichiura, and 6.36% for S. stercoralis. The sedimentation/concentration method was the most sensitive for A. lumbricoides (96%), compared to the McMaster method, with a sensitivity of 62%. Similarly, for hookworms, sedimentation/concentration was more sensitive than McMaster's, Harada-Mori, and Baermann with sensitivities of 87%, 70%, 43%, and 13%, respectively. Most of these infections were of light intensity. For S. stercoralis, Baermann and sedimentation/concentration methods were the most sensitive, with 70% and 62% respectively, while Harada-Mori was the least sensitive. In a subset of 389 samples also analyzed by the APC, Baermann was more sensitive than APC for detecting S. stercoralis, and both methods were superior to Harada-Mori. Parasitological methods, mostly when used combined, offer adequate opportunities for the diagnosis of STH in clinical and public health laboratories. The incorporation of S. stercoralis into the control strategies of the World Health Organization requires rethinking the current diagnostic approach used for surveys. With sedimentation/concentration and Baermann appearing as the most sensitive methods for this species. Further studies, including implementation assessments, should help in identifying the most adequate and feasible all-STH diagnostic approach.

Strongyloides causing diarrhea in a Hepatitis B carrier patient: A case report and review of literature

We report an unusual case of strongyloidiasis in a 62-year-old male, presenting with fever, and acute diarrhea. The patients had concomitant bilateral renal parenchymal disease and carrier for Hepatitis B. Numerous motile larvae were observed in wet mount of the freshly passed stool. The patient responded well to oral ivermectin. Prompt and accurate diagnosis of strongyloidiasis can prevent the consequences associated with hyperinfective syndrome.

High-throughput sequencing of Strongyloides stercoralis - a fatal disseminated infection in a dog

The rhabditid nematode Strongyloides stercoralis is known worldwide as the causative agent of strongyloidiasis in humans. In addition to public health concerns, S. stercoralis also infects dogs, which represent a possible reservoir for potentially zoonotic transmissions. We describe the first confirmed case of fatal disseminated infection in a dog in the Czech Republic. The microscopic and histological results were supported by a complex genotyping approach. Using high-throughput sequencing of the hypervariable region (HVR-IV) of 18S rDNA and Sanger sequencing of the partial cytochrome c oxidase subunit 1 gene (cox1), the potentially zoonotic haplotype/lineage A of S. stercoralis was confirmed, while the solely canine haplotype/lineage B was not found. The development of the disease is mainly associated with immunodeficiency, and in this case, it was triggered by inappropriate treatment, in particular the use of corticosteroids.

Enhancing screening adherence for strongyloides infection in latinx inpatients with COVID-19: a local protocol implementation study

Strongyloides stercoralis hyperinfection syndrome has been observed in immunosuppressed coronavirus disease 2019 (COVID-19) patients. Detecting and treating asymptomatic Strongyloides infection in individuals from endemic areas can effectively prevent hyperinfection. Unfortunately, many clinicians are unaware of this neglected infection. Therefore, we aimed to evaluate whether including Strongyloides screening in COVID-19 management protocols would encourage this practice. To accomplish this, we conducted a retrospective single-center study at 'Hospital Universitario 12 de Octubre' in Madrid, Spain, comparing two consecutive cohorts. The first cohort comprised all Latinx patients over 18 years old who were admitted for COVID-19 between March 1st and April 30th, 2020. The second cohort consisted of Latinx patients admitted between July 1st and December 31st, 2020, following an amendment to the COVID-19 management protocol that recommended screening for strongyloidiasis in at-risk patients. We identified 559 and 795 patients in the first and second periods, respectively. The percentage of individuals screened increased significantly from 8.8% to 51.6% after the screening recommendation was included in the protocol (odds ratio [OR] 11.08, 95% confidence interval [CI] 8.01-15.33). In both periods, the screening rate was significantly higher among those receiving immunosuppression than those who did not receive steroids and/or tocilizumab. No other factors influenced the screening rate. In conclusion, including strongyloidiasis screening recommendations in COVID-19 management protocols led to its increased implementation. However, the overall screening rate remained low, emphasizing the need for further efforts to enhance screening practices.

Factors associated with the sexual transmission of Strongyloides stercoralis in men who have sex with men: A systematic review

Strongyloides stercoralis is a parasitic worm with a complex life cycle and can cause significant morbidity, including a proctocolitis and life-threatening hyperinfection syndrome. Limited reports from non-endemic areas, including in men who have sex with men (MSM), suggest sexual transmission of S. stercoralis. In this systematic review of the published literature, we aimed to explore the associated factors of S. stercoralis in MSM. We systematically searched three bibliographical databases (MEDLINE, CINAHL and EMBASE) up to November 2022. We used a two-stage process to assess eligibility: the primary author conducted an initial screen of abstracts, and then three authors conducted independent full manuscripts to determine the final eligible manuscripts. We only included manuscripts written in English that contained data on specific factors associated with sexual transmission in MSM. We used the STROBE checklist to assess the risk of bias and synthesized the narrative data using the SWiM method. Seven manuscripts were eligible for this review (four case reports, one case series, one cross-sectional study and one experimental study), which included 22 individuals from Europe and the Americas. From these studies, S. stercoralis in MSM was associated with living with HIV (including having a low CD4 count and not using antiretrovirals), having a concomitant sexually transmitted infection (Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum and hepatitis C) and a concomitant (sexually transmitted) protozoal infection (Entamoeba histolytica, Giardia lamblia), travel to the S. stercoralis endemic area, multiple sexual partners from endemic areas, oro-anal sexual contact and chemsex. Although limited by the number of cases in the literature, we have highlighted some possible biological and behavioural risk factors associated with the sexual transmission of S. stercoralis in MSM that could be used to both target future research and S. stercoralis public health control interventions.

Generation of IgG antibodies against Strongyloides stercoralis in mice via immunization with recombinant antigens A133 and Ss-IR

Strongyloidiasis, caused by the nematode Strongyloides stercoralis, remains a threat to global public health, and a vaccine would be useful to control the disease, especially in developing countries. This study aimed to evaluate the efficacy of recombinant proteins, A133 and Ss-IR, as potential vaccine candidates against strongyloidiasis by investigating the humoral and cellular immune responses in immunized mice. Respective antigens were adjuvanted with Complete Freund's Adjuvant (prime) and Incomplete Freund's Adjuvant (boost) and administered intraperitoneally (prime) and subcutaneously (boost) to female BALB/c mice. For antigen-only doses, only antigens were injected without adjuvants. Altogether, 1 prime dose, 4 booster doses, and 2 antigen-only doses were administered successively. ELISAs were conducted to assess the antibody responses, along with flow cytometry and cytokine ELISA to elucidate the cellular immune responses. Results showed that A133 and Ss-IR induced the production of IgG1 and IgG2a, with A133 generating more robust IgG2a responses than Ss-IR. Flow cytometry findings indicated that effector CD8+T-cells and memory B-cells activity were upregulated significantly for A133 only, whereas cytokine ELISA demonstrated that a Th1/Th2/Th17 mixed cell responses were triggered upon vaccination with either antigen. This preliminary study illustrated the good potential of recombinant A133 and Ss-IR as vaccine candidates against S. stercoralis. It provided information on the probable immune mechanism involved in host defence and the elicitation of protection against S. stercoralis.

Examination of Diagnostic Performance of New IgG4 Rapid Test Compared with IgG- and IgG4-ELISAs to Investigate Epidemiology of Strongyloidiasis in Northeast Thailand

Strongyloidiasis, caused by Strongyloides stercoralis, is a neglected tropical disease with a global distribution. The infection can be fatal in immunocompromised individuals, and accurate diagnosis leading to timely treatment can save lives. Serodiagnosis is a sensitive method for diagnosis and is recommended for screening high-risk individuals. A point-of-care rapid test will facilitate the screening activities, especially in low-resource settings. This study aims to apply a new IgG4 immunochromatographic test using S. stercoralis recombinant antigen (SsRapid® cassette test) and to compare it with in-house IgG and IgG4 enzyme-linked immunosorbent assays (IgG- and IgG4-ELISAs) using native Strongyloides ratti antigen to investigate the epidemiology of strongyloidiasis in northeast Thailand. A total of 300 people participated, with 136 males and 164 females of a similar mean age. The reference tests were fecal examinations using the formalin-ethyl acetate concentration technique and an agar plate culture technique. The prevalence of S. stercoralis determined by SsRapid (81.7%) was significantly higher than that by fecal examinations (43.3%) or by antibody detection by IgG-ELISA (53.0%) or IgG4-ELISA (44.0%). The diagnostic sensitivities of SsRapid, IgG-ELISA, and IgG4-ELISA were found to be 93.9%, 77.7%, and 63.1%, respectively. The rate of positive tests by the SsRapid was significantly correlated to the levels of Strongyloides-specific IgG4 and IgG antibodies. By all diagnostic methods, male participants had a significantly higher prevalence of strongyloidiasis than females. Age was significantly associated with the concentration of specific serum IgG but not with the SsRapid grading score. In conclusion, SsRapid was shown to be a sensitive and valuable diagnostic test for the epidemiology study of strongyloidiasis.

Modifications to the parasitological technique of Rugai increase the diagnostic sensitivity for strongyloidiasis

Strongyloidiasis is a neglected tropical disease caused mainly by Strongyloides stercoralis, a nematode that can persist for decades in the human host with a very low parasitic burden and without specific symptoms. Hence, it is difficult to diagnose and control. Larval concentration and culture methods with fecal samples show higher sensitivity for the diagnosis of Strongyloides-infected individuals; however, these techniques are not routinely used, primarily due to the challenges associated with processing a substantial volume of fecal samples. In the current study, we comparatively evaluated the sensitivity and applicability of modifications made to the Rugai parasitological method for the diagnosis of strongyloidiasis in fecal samples of experimentally infected rats and in 68 individuals from an urban community close to Maceió, Brazil. The presence and quantity of parasite larvae in the feces were comparatively evaluated using different parasitological techniques. In the experimental model, we demonstrated that the modified Rugai technique (RMOD) allowed for significantly higher recovery of larvae than the original Rugai technique (RO). Moreover, the sediment was cleaner and easier to evaluate using optical microscopy. Compared to other parasitological techniques, such as agar-plate culture (A-PC) and spontaneous sedimentation (SS), the RMOD technique showed higher sensitivity in the detection of larvae in all infected groups and presented comparatively better performance, especially in rats with a low parasite burden. In the human population, among the 68 stool samples evaluated, Strongyloides larvae were detected in the feces of six individuals with an estimated prevalence of 8.82%. However, the performance of each parasitological method was remarkably different. SS identified Strongyloides larvae in only two individuals and A-PC in three, whereas RMOD was able to identify six infected individuals, resulting in sensitivities of 33.3%, 50%, and 100%, respectively. In conclusion, the modifications introduced to the Rugai technique resulted in improved sensitivity for the detection of Strongyloides spp. infections, especially in stool samples with a low parasite burden, in comparison with other routinely used parasitological techniques.

Strongyloides stercoralis genotyping in a human population in southwestern Iran

BACKGROUND

Strongyloidiasis is a neglected tropical disease (NTD) that is caused mainly by Strongyloides stercoralis, with an estimated 600 million people infected worldwide, and in fewer cases by Strongyloides fuelleborni fuelleborni and Strongyloides fuelleborni kellyi. A number of studies have been conducted on the genetic diversity of S. stercoralis in East and Southeast Asia; however, there is very limited corresponding information from West Asian countries, including Iran.

METHODS

For Strongyloides worms collected from patients in southwestern Iran, the hypervariable regions I (HVR-I) and IV (HVR-IV) of the nuclear 18S ribosomal DNA (rDNA) locus (SSU) and a fragment of the subunit 1 mitochondrial cytochrome c oxidase gene (cox-1) were sequenced. For a subset of the worms, whole-genome sequencing data were generated.

RESULTS

The cox-1 sequences of 136 worms isolated from 23 patients indicated that all isolates were S. stercoralis. Among the cox-1 sequences, 33 polymorphic sites and 13 haplotypes were found. The phylogenetic analysis demonstrated that some sequences clustered fairly closely with sequences from humans and dogs from other parts of the world, while others formed a separate, Iran-specific group. Among 64 S. stercoralis analyzed, we found three of the previously described SSU HVR-I haplotypes, with haplotype II being the most frequent haplotype. In contrast to Southeast Asia, where S. stercoralis heterozygous for different haplotypes at the HVR-I locus are rare, we found 20 worms to be heterozygous for two different HVR-I haplotypes, 18 of which fell into the Iran-specific cox-1 cluster. SSU-heterozygous worms also showed elevated heterozygosity at the whole-genome level.

CONCLUSIONS

We conclude that the S. stercoralis population from the Khuzestan province shares much of the genetic diversity with the population in Southeast Asia, but there is an indication of additional genetic input. There appears to be some population structure with different subpopulations, which however do interbreed at least occasionally.

The transmission dynamics of Strongyloides stercoralis and the impact of mass drug administration

The epidemiology of Strongyloides stercoralis is briefly reviewed with an emphasis on cross section and longitudinal studies of infection prevalence stratified by age, performance of different diagnostic tools, mass drug administration (MDA) impact and estimates of key population parameters within the complex life cycle of the parasite that determine transmission intensity and response to control measures. The paucity of studies is highlighted, and gaps in current knowledge identified about the population biology of this very prevalent infection in tropical and sub-tropical regions around the world. A stochastic individual based stochastic model is described in part to highlight gaps in knowledge. The impact of repeated MDA is simulated to illustrate some aspects of transmission dynamics of this helminth infection. Specifically, the impact and bounce back times in either the intervals between treatment rounds, or post the cessation of treatment, depend critically on the magnitude of two distinct components of the basic reproductive number R0. The absence of data on these key components is highlighted, as is the value of studies of longitudinal cohorts of people in regions of endemic infection post rounds of MDA to record how infection levels bounce back post treatment at individual and population levels of study. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.

Massive Airway Bleeding Caused by Pulmonary Strongyloidiasis in a Patient with a Transplanted Kidney

Introduction

We report a fatal case of massive airway bleeding caused by pulmonary strongyloidiasis in a patient with a transplanted kidney.

Case Presentation

A 47-year-old male, regularly taking immunosuppressants post-kidney transplant, visited our hospital with symptoms of abdominal bloating, nausea, and emesis persisting for three days. After hospitalization, he developed a cough, hemoptysis, and respiratory failure. Sputum analysis confirmed an infestation with Strongyloides stercoralis. Despite receiving albendazole therapy and bronchoscopic management for bronchial hemorrhage, the patient ultimately died due to acute respiratory and circulatory collapse triggered by severe airway bleeding.

Conclusion

Patients undergoing immunosuppressive therapy following kidney transplantation are at increased risk for disseminated strongyloidiasis. Consequently, infectious disease screening prior to transplantation, along with essential preventive pharmacotherapy, is of paramount importance.

Improved diagnostic sensitivity of human strongyloidiasis using point-of-care mixed recombinant antigen-based immunochromatography

Strongyloidiasis is a neglected tropical disease that can cause fatal complications due to hyperinfection and disseminated strongyloidiasis in immunocompromised patients. We used two Strongyloides stercoralis recombinant antigenic proteins, L3NieAg.01 (NIE) and IgG-immunoreactive antigen (SsIR), to develop the recombinant antigen-based immunochromatography test (ICT) kit. We constructed and compared kits using either the NIE (NIE ICT kit) or the SsIR (SsIR ICT kit) antigens and a kit using a mixture of both (NIE-SsIR ICT kit) for detection of anti-Strongyloides IgG antibody in human serum samples. Serum samples from normal healthy individuals (Group I, n = 40), proven strongyloidiasis patients (Group II, n = 100), and those with other parasitic infections (Group III, n = 154) were evaluated. Sensitivity and specificity were 81.0% and 84.0% for the NIE ICT kit, 89.0% and 83.5% for the SsIR ICT kit, and 95.0% and 90.2% for the NIE-SsIR ICT kit, respectively. The NIE-SsIR ICT kit provided the best diagnostic results; it can supplement stool examination for clinical diagnosis and can be used to screen for asymptomatic S. stercoralis infection in people at risk in endemic areas. The NIE-SsIR ICT kit can also be used in large-scale sero-epidemiological investigations in endemic areas without the need for additional facilities or ancillary supplies.

Strongyloides stercoralis Infection in Humans: A Narrative Review of the Most Neglected Parasitic Disease

Strongyloidiasis is a helminth infection affecting 613.9 million people annually, mainly in the tropics and subtropics. The reported seroprevalence in the United States is 4% with most of the cases reported in immigrants. Human T-lympho-tropic virus 1 (HTLV-1) infections, hypogammaglobulinemia, immunosuppressant use - particularly steroid use, alcoholism, and malnutrition have been associated with an increased risk of strongyloidiasis. Recently, cases of strongyloidiasis hyperinfection syndrome have been described in coronavirus disease 2019 (COVID-19) patients treated with steroids as well. This brief review discusses the epidemiology, clinical features, management, and prevention of strongyloidiasis including some facts about the infection in pregnancy, transplant recipients, and COVID-19 patients. We conducted an online search using the PubMed, Scopus, and Google Scholar databases. Strongyloidiasis can be asymptomatic or present with mild symptoms. Strongyloides stercoralis is known to cause autoinfection. In immunocompromised individuals, it can present with severe symptoms, hyperinfection, or disseminated disease. Reported mortality in cases of disseminated Strongyloidiasis is 87.1%. Serology and detection of larvae in stool by direct microscopy are the most commonly used methods to diagnose strongyloidiasis. The drug of choice for the treatment is ivermectin. However, the use of ivermectin in human pregnancy is not well studied, and its teratogenic risks are unknown. Proactive screening of strongyloidiasis is necessary in immunocompromised individuals to prevent severe disease.

Implementation and Outcomes of an Empiric Ivermectin Strongyloides Treatment Protocol for Patients Receiving High-Dose Corticosteroids for Severe COVID-19

Strongyloides stercoralis is a parasitic roundworm that is present worldwide and can cause lifelong, often asymptomatic, infection. Immunosuppression, particularly by corticosteroids, is a risk factor for hyperinfection syndrome and disseminated strongyloidiasis-severe disease states that can lead to septic shock and death. Our institution implemented a strongyloidiasis screening and empiric ivermectin treatment protocol for inpatients receiving high-dose corticosteroids for severe COVID-19. Among 487 COVID-19 admissions treated with high-dose corticosteroids from June 10, 2020 to March 31, 2021, 61% of those with demographics at risk for Strongyloides exposure were screened for Strongyloides and treated empirically with ivermectin. Adherence to the protocol declined over time during the study period. The empiric ivermectin protocol appeared safe, but more research is needed to determine the effect on hyperinfection and/or disseminated strongyloidiasis risk and mortality rate, as well as to improve institutional adherence to the protocol.

Diagnostic performance of Strongyloides-specific IgG4 detection in urine for diagnosis of human strongyloidiasis

BACKGROUND

Detection of parasite-specific IgG in urine is a sensitive method for diagnosis of strongyloidiasis and gives similar accuracy to serum IgG. However, there are no data concerning detection of IgG subclass in urine. To further explore the utility of diagnosis from urine samples, we evaluated the diagnostic performance of IgG4 in urine compared with parasitological and other immunological methods.

METHODS

The urine and sera included proven strongyloidiasis (group 1, n = 93), other parasitic infections (group 2, n = 40) and parasite negatives (group 3, n = 93). The performance of Strongyloides-specific IgG4 in urine for diagnosis of strongyloidiasis using fecal examinations as the reference standard was assessed.

RESULTS

With fecal examination as a gold standard, Strongyloides-specific IgG4 in urine had 91.4% sensitivity and 93.2% specificity while serum IgG4 had 93.6% sensitivity and 91.0% specificity. IgG4 in both urine and serum had almost perfect diagnostic agreements with fecal examination (Cohen's kappa coefficient was > 0.8). Cross-reactivity to Opisthorchis viverrini and Taenia spp. of IgG4 in urine were 7.5% and 12.5% in serum. Concurrent analyses of total IgG in urine and serum showed that the sensitivities (97.9-100%) and specificities (88.7-91.0%) were similar (P > 0.05). The sensitivity for parasitological examination by the formalin-ethyl acetate concentration technique (FECT) was 49.5% and that for agar plate culture technique (APC) it was 92.6%.

CONCLUSION

Our findings showed that specific IgG4 detection in urine yielded similar diagnostic performance to the same biomarkers in serum. This suggests that accurate diagnosis of strongyloidiasis can be performed using urine samples and IgG4 is a valid choice of diagnostic marker. Further assessment is required to assess the utility of urine IgG4 for measuring the response treatment in strongyloidiasis.

A case of strongyloidiasis with aplastic anaemia: A common disease with an uncommon presentation

Strongyloidiasis is an opportunistic infection caused by the nematode helminth Strongyloides stercoralis and transmitted mostly via soil. The disease is usually asymptomatic, limited, and long-standing. Herein, we report a case of strongyloidiasis in a patient who seemed to be immunocompetent despite his malnourished appearance. He was presented with pancytopenia and aplastic anaemia and well responded to albendazole therapy with complete resolution of symptoms within three months. We recommend, prior to beginning of immunosuppressive regimens, it may be prudent to examine all patients presenting with abdominal discomfort along with pancytopenia for a possible worm infestation. Bone marrow suppression induced by worm infestation is an extremely rare but potentially comorbid condition that can lead to pancytopenia and severe aplastic anaemia.

Strongyloidiasis-related lung involvement: too much of a bad thing

PURPOSE OF REVIEW

Strongyloidiasis is a soil-transmitted helminthiasis, a neglected tropical disease that affects 300-900 million individuals globally. Strongyloides stercoralis is associated with cutaneous, respiratory, and gastrointestinal clinical manifestations. Chronicity is due to an autoinfective cycle, and host immunosuppression can lead to severe and fatal disease. Lung involvement is significant in severe strongyloidiasis, and Strongyloides has a complex association with a number of lung diseases, which will be discussed in this review.

RECENT FINDINGS

The treatment of chronic lung diseases such as asthma and chronic obstructive pulmonary disease with corticosteroids is an important risk factor for Strongyloides hyperinfection syndrome (SHS)/disseminated strongyloidiasis. The use of corticosteroids in the treatment of coronavirus disease 2019 (COVID-19) and potentially COVID-19-induced eosinopenia are risk factors for severe strongyloidiasis. Recent findings have demonstrated a significant immunomodulatory role of Strongyloides in both latent and active pulmonary tuberculosis associated to an impaired immune response and poor outcomes in active pulmonary tuberculosis.

SUMMARY

Strongyloides lung involvement is a common finding in severe infection. Prompt recognition of Strongyloides infection as well as prevention of severe disease by screening or presumptive treatment are important goals in order to improve Strongyloides outcomes in at-risk population.

Endemic or regionally limited parasitic and fungal infections in haematopoietic stem-cell transplantation recipients: a Worldwide Network for Blood and Marrow Transplantation (WBMT) Review

There is a scarcity of data on endemic and regionally limited fungal and parasitic infections in recipients of haematopoietic stem-cell transplantation (HSCT) outside western Europe and North America. This Worldwide Network for Blood and Marrow Transplantation (WBMT) Review is one of two papers aiming to provide guidance to transplantation centres worldwide regarding prevention, diagnosis, and treatment based on the currently available evidence and expert opinion. These recommendations were created and reviewed by physicians with expertise in HSCT or infectious disease, representing several infectious disease and HSCT groups and societies. In this paper, we review the literature on several endemic and regionally limited parasitic and fungal infections, some of which are listed as neglected tropical diseases by WHO, including visceral leishmaniasis, Chagas disease, strongyloidiasis, malaria, schistosomiasis, histoplasmosis, blastomycosis, and coccidioidomycosis.

Strongyloides and COVID-19: Challenges and Opportunities for Future Research

Strongyloides stercoralis is a soil transmitted helminth endemic to tropical and subtropical areas that can persist for decades in immunocompetent human hosts as a chronic asymptomatic infection. The use of corticosteroids, a mainstay of treatment for patients hospitalized with severe coronavirus disease (COVID-19), can trigger a life-threatening Strongyloides hyperinfection syndrome and disseminated disease. We identified 22 previously published cases of strongyloidiasis occurring in individuals with COVID-19, with one death reported among the seven patients who had Strongyloides hyperinfection syndrome. A total of seventeen patients had previously received corticosteroids, and of the five with no prior corticosteroid use, one presented with hyperinfection syndrome. We identify the key challenges in the diagnosis and treatment of Strongyloides within the context of COVID-19, including our imprecise knowledge of the global distribution of Strongyloides, the overlapping symptoms and signs of COVID-19 and Strongyloides hyperinfection syndrome, the limited utility of eosinophilia as a clinical marker for strongyloidiasis in this setting, the lack of validated algorithms to screen for Strongyloides prior to corticosteroid use, and the paucity of treatment options for critically ill patients with COVID-19 who cannot take oral ivermectin. Future research should focus on improved diagnostic methods and population prevalence estimates, optimizing the approaches for Strongyloides screening in persons with COVID-19 (including clinical trial participants and strategies for resource-limited settings) and better defining the role of pre-emptive treatment.

Prevalence and risk factors of Strongyloides stercoralis in haemodialysis in Cochabamba, Bolivia: a cross-sectional study

BACKGROUND

Strongyloidiasis is an infectious disease that can be fatal in immunocompromised patients. Patients with end-stage renal failure who are on dialysis have a considerably weakened immune system, and organ transplantation is a major risk factor for severe strongyloidiasis. Knowledge of the local epidemiology in tropical and subtropical areas is an essential prerequisite for designing an appropriate strategy to prevent this potentially lethal complication. In this study, we aimed to estimate the prevalence and associated risk factors of S. stercoralis infection in patients on dialysis in Cochabamba, Bolivia.

METHODS

A cross-sectional study was carried out among patients undergoing haemodialysis in Cochabamba (elevation 2,500 m, temperate climate), collecting information on socio-demographic, lifestyle, and clinical variables, and using one coproparasitological technique (the modified Baermann technique) and one serological (ELISA) test for S.stercoralis diagnosis.

RESULTS

In total, 149 patients participated in the study (mean age = 51.4 years, 48.3% male). End-stage renal disease was predominantly (59%) of hypertensive and/or diabetic origin. The positive serological prevalence was 18.8% (95% CI: 13.3%-25.9%). Based on the sensitivity and specificity of the ELISA test, the estimate of the actual prevalence was 15.1% (95% CI: 9.4%-20.7%). Stool samples of 105 patients (70.5%) showed a coproparasitological prevalence of 1.9% (95% CI: 0.52%-6.68%). No potential risk factors were significantly associated with S. stercoralis infection.

CONCLUSIONS

We found a high seroprevalence of S. stercoralis in Bolivian patients undergoing haemodialysis in Cochabamba. We recommend presumptive antiparasitic treatment at regular intervals to avoid the potentially fatal complications of severe strongyloidiasis.

Epidemiology, clinical features, and outcomes of strongyloidiasis in Taiwan from 1988 to 2020: A case series and literature review

OBJECTIVES

We described a case of Strongyloides hyperinfection syndrome, reported a case series, and reviewed published cases of strongyloidiasis in Taiwan.

METHODS

Confirmed cases of strongyloidiasis at the National Taiwan University Hospital (NTUH) and NTUH Hsin-Chu Branch from 1988 to 2020 were identified in the medical record database. Literature search was carried out through Pubmed, Google Scholar, and Index to Taiwan Periodical Literature System to identify published cases of strongyloidiasis in Taiwan from 1979 to 2020. Data pertaining to the demographics, underlying medical conditions, clinical manifestations, laboratory findings, and outcomes were extracted.

RESULTS

A total of 117 cases of strongyloidiasis were identified, including 20 previously unpublished cases from the two hospitals and 97 published cases in the literature. Overall, 85 (73%) were male and the mean age was 64 years (range, 6-95 years). Classical symptoms such as diarrhea, cough, and skin rash were only observed in 43%, 37%, and 18% of the patients, respectively, whereas eosinophilia at presentation was only found in 48%. Strongyloides hyperinfection syndrome and disseminated strongyloidiasis were identified in 41 (35%) and 4 (3%) patients, respectively. Four (3%) patients had concurrent meningitis. In univariable analysis, being older and having pre-existing chronic obstructive pulmonary disease or asthma were associated with hyperinfection or dissemination (p = 0.024 and 0.003, respectively). The mortality rate was 43% among those with hyperinfection or disseminated infection.

CONCLUSIONS

Strongyloidiasis can cause serious complications and mortality. Efforts to diagnose strongyloidiasis early are urgently needed to improve the outcome of patients with strongyloidiasis in Taiwan.

Seroprevalence and microscopy detection rates of strongyloidiasis in Croatian patients with eosinophilia

Infection with the parasitic nematode Strongyloides stercoralis is characteristic for tropical and subtropical regions of the world, but autochthonous cases have been reported in European countries as well. Here we present the first nation-wide survey of S. stercoralis seroprevalence in Croatian individuals presenting with eosinophilia, and evaluate the fraction of positive microscopy rates in stool specimens of seropositive individuals. In our sample of 1407 patients tested between 2018 and 2021, the overall prevalence of strongyloidiasis was 9.31%, with significantly higher rates in those older than 60 years of age (P = 0.005). Of those, one-quarter (25.95%) were also positive following microscopy examination of faeces after using the merthiolate-iodine-formaldehyde concentration method. Our findings reinforce the notion of endemic strongyloidiasis transmission in Croatia, particularly in older individuals, and highlight the need to consider the presence of S. stercoralis in patients with eosinophilia.

Strongyloidiasis presenting during treatment of low-dose glucocorticoid plus rituximab for anti-signal recognition particle antibody-positive polymyositis: A case report

Strongyloidiasis, an intestinal parasitic infection caused by Strongyloides stercoralis, rarely occurs in Japan. When treated with immunosuppressive drugs, two potentially lethal conditions, hyperinfection and dissemination, may develop in asymptomatic carriers of this parasite. We report the development of strongyloidiasis during treatment of polymyositis with glucocorticoids plus rituximab (RTX). A 44-year-old woman had been diagnosed with anti-signal recognition particle antibody-positive polymyositis with interstitial pneumonia 6 years previously, for which she had recently been receiving prednisolone at 5 mg/day and RTX at 375 mg/m2 twice every 3 months. Her condition appeared to be well controlled. She was admitted to our hospital with a 1-month history of chronic diarrhoea and epigastric pain. Standard microscopic examination of a sample of faeces revealed the presence of S. stercoralis; however, serologic testing for parasites was negative. Treatment with ivermectin alleviated her inflammatory diarrhoea and eradicated the faecal parasites. We believe that our patient had an exacerbation of S. stercoralis infection (hyperinfection syndrome) that was exacerbated by low-dose glucocorticoids plus RTX. Strongyloidiasis should be considered in immunocompromised individuals with unexplained diarrhoea, even in non-endemic areas.

An adaptive phase II/III safety and efficacy randomized controlled trial of single day or three-day fixed-dose albendazole-ivermectin co-formulation versus albendazole for the treatment of Trichuris trichiura and other STH infections. ALIVE trial protocol

Background: Soil-transmitted helminths (STH) are targeted for control through mass drug-administration campaigns to prevent morbidity affecting at-risk groups in endemic regions. Although broadly successful, the use of albendazole and mebendazole achieved variable progress, with deficiencies against Trichuris trichiura and a predictable low efficacy against Strongyloides stercoralis. Novel drug combinations offer a potential solution, providing they can be delivered safely and maintain efficacy against all STH species. Here we present the protocol of a clinical trial to evaluate a fixed-dose combination (FDC) tablet containing albendazole and ivermectin that will be compared against albendazole against STH . Methods: An adaptive phase II/III randomized controlled trial will be undertaken in STH endemic sites in Ethiopia, Kenya and Mozambique to evaluate an oral FDC of 400 mg albendazole and either 9- or 18 mg ivermectin. FDC will be administered as a single dose or single doses over three-consecutive days and assessed against a single dose of 400 mg albendazole. In the phase II trial, 126 T. trichiura-infected children weighting 15 to 45 kg will be treated in a dose-escalation manner to determine safety objectives. In the phase III trial, 1097 participants aged 5 to 18 years old infected with T. trichiura, hookworm and S. stercoralis will be recruited to determine safety and efficacy. The trial will be open-label with blinded outcome assessors. Cure rate measured 21-days after-treatment in duplicate Kato-Katz is the primary efficacy outcome. Secondary objectives include efficacy evaluation by quantitative polymerase chain reaction (PCR) as an outcome measurement, description of pharmacokinetic parameters, palatability and acceptability evaluations, and monitoring of anthelmintic resistance. Conclusions: This trial with registrational goals seeks to evaluate an innovative fixed-dose combination of albendazole and ivermectin co-formulated tablets, with the goal of providing an anthelmintic regimen with improved efficacy and spectrum of coverage against STH. ClinicalTrials.gov registration: NCT05124691 (18/11/2021).

Evaluation of a Geographic Screening Protocol for Chronic Parasitic Infections Before Kidney Transplant: An Institutional Experience in Minnesota

Pretransplant recommendations advise risk-based screening for strongyloidiasis, schistosomiasis, and Chagas disease. We evaluated the implementation of a chronic parasite screening protocol at a health system in a nonendemic region serving a large foreign-born population. Candidates listed for kidney transplant at Hennepin Healthcare (Minneapolis, MN) between 2010 and 2020 were included. Country of birth and serologic screening for strongyloidiasis, schistosomiasis, and Chagas disease were retrospectively obtained from electronic medical records. Parasite screening frequency and seropositivity was assessed before and after implementation of a geographic risk factor-based screening protocol in 2014. Cost-efficiency of presumptive treatment was modeled. Of 907 kidney transplant candidates, 312 (34%) were born in the United States and 232 (26%) outside the United States, with the remainder missing country of birth information. The 447 (49%) candidates evaluated after implementation of the screening protocol had fewer unidentified countries of birth (53%-27%, P < 0.001) and were more frequently screened for strongyloidiasis, schistosomiasis, and Chagas disease (14%-44%, 8%-22%, and 1-14%, respectively, all Ps < 0.001). The number of identified seropositive candidates increased after protocol implementation from two to 14 for strongyloidiasis and from one to 11 for schistosomiasis, with none seropositive for Chagas disease. The cost-efficiency model favored presumptive ivermectin when strongyloidiasis prevalence reaches 30% of those screened. Implementing a geographic risk screening protocol before kidney transplant increases attention to infectious disease risk associated with country of birth and identification of chronic parasitic infections. In populations with higher strongyloidiasis prevalence or lower ivermectin costs, presumptive treatment may be cost-efficient.

Frequency and characteristics of HTLV in migrants: results from the +Redivi collaborative network in Spain

INTRODUCTION

The objective of this study was to describe the main characteristics of migrants diagnosed with human T-lymphotropic virus (HTLV) infection within the +Redivi Spanish network.

METHODS

Patients with a diagnosis of HTLV type 1 or 2 in +Redivi from October 2009 to December 2020 were included. Diagnosis was based on positive HTLV serology (enzyme-linked immunosorbent assay (ELISA)/chemiluminescent immunoassay (CLIA)) with line immunoassay (LIA)/Western blot with/without polymerase chain reaction (PCR).

RESULTS

A total of 107/17 007 cases (0.6%) had a final diagnosis of HTLV infection: 83 (77.67%) HTLV-1 infections, 6 (5.6%) HTLV-2 infections and 18 (16.8%) non-specified. The majority (76, 71%) were female, median age was 42 years and median time from arrival to Spain until consultation was 10 years. The group included 100 (93.5%) immigrants and 7 (6.6%) visiting friends and relatives (VFR)-immigrants. Most patients were from South America (71, 66.4%), followed by Sub-Saharan Africa (15, 14%) and Central America-Caribbean (13, 12.1%). Around 90% of patients were asymptomatic at presentation and diagnosed as part of screening programs. Median duration of follow-up was 5 years (IQR 2-7). Regarding HTLV-associated conditions, 90 patients (84.2%) had none, 7 (6.5%) had tropical spastic paraparesis , 5 (4.7%) had other associated conditions (dermatitis, uveitis, pulmonary disease), 3 (2.8%) had other neurological symptoms and 2 (1.9%) had adult T-cell leukaemia/lymphoma. No patients with HTLV-2 had HTLV-associated conditions. Four patients (3.7%) died. Concomitant diagnoses were found in 41 (38.3%) patients, including strongyloidiasis in 15 (14%) and HIV co-infection in 4 (3.7%). In 70% of patients, screening of potential contacts was not performed/recorded.

CONCLUSIONS

HTLV infections (the majority due to HTLV-1) were mainly diagnosed in asymptomatic migrants from Latin America (generally long-settled immigrants and the majority female with the consequent implications for screening/prevention). A high rate of association with strongyloidiasis was found. In the majority, screening of potential contacts was not performed, representing a missed opportunity for decreasing the under diagnosis of this infection.

Strongyloides stercoralis: A Neglected but Fatal Parasite

Strongyloidiasis is a disease caused by Strongyloides stercoralis and remains a neglected tropical infection despite significant public health concerns. Challenges in the management of strongyloidiasis arise from wide ranging clinical presentations, lack of practical high sensitivity diagnostic tests, and a fatal outcome in immunocompromised hosts. Migration, globalization, and increased administration of immunomodulators, particularly during the COVID-19 era, have amplified the global impact of strongyloidiasis. Here, we comprehensively review the diagnostic tests, clinical manifestations, and treatment of strongyloidiasis. The review additionally focuses on complicated strongyloidiasis in immunocompromised patients and critical screening strategies. Diagnosis of strongyloidiasis is challenging because of non-specific presentations and low parasite load. In contrast, treatment is simple: administration of single dosage ivermectin or moxidectin, a recent anthelmintic drug. Undiagnosed infections result in hyperinfection syndrome and disseminated disease when patients become immunocompromised. Thus, disease manifestation awareness among clinicians is crucial. Furthermore, active surveillance and advanced diagnostic tests are essential for fundamental management.

Strongyloides stercoralis hyperinfection syndrome mimicking pseudomembranous enteritis, complicated by Escherichia coli bacteremia and Pneumocystis jirovecii pneumonia in a patient after immunosuppressive therapy: a case report

Background

Strongyloidiasis, caused by Strongyloides stercoralis (S. stercoralis), is endemic worldwide, especially in countries with warm and humid climates. Strongyloides stercoralis hyperinfection syndrome (SHS) is an extremely serious manifestation of strongyloidiasis, which results from an acute exacerbation of auto-infection and is often fatal.

Case presentation

We present a case of SHS mimicking pseudomembranous enteritis with a final definitive diagnosis of a triple infection including S. stercoralis, Escherchia coli (E. coli) and Pneumocytis jirovecii (P. jirovecii) that occurred in a microscopic polyangiitis (MPA) patient after immunosuppressive therapy. SHS, together with E. coli bacteremia and Pneumocytis jirovecii pneumonia (PJP) in the same patient, is rare in clinical practice, which is first reported worldwide, to our knowledge. After the diagnosis was confirmed, the treatment protocol was quickly adjusted; however, the patient’s life could not be saved.

Conclusion

This case reminds us of the necessity to consider strongyloidiasis as a differential diagnosis in immunocompromised populations who live in or have visited to S. stercoralis endemic areas, especially patients with suspected pseudomembranous enteritis, even if stool examination, serological tests, and eosinophilia are negative. For this group, it is advisable to complete the relevant endoscopy and/or PCR as soon as possible. The fundamental solution to prevent this catastrophic outcome is to implement effective preventive measures at multiple levels, including physicians, patients, and relevant authorities.

Strongyloides stercoralis infection induces gut dysbiosis in chronic kidney disease patients

Background

Strongyloides stercoralis infection typically causes severe symptoms in immunocompromised patients. This infection can also alter the gut microbiota and is often found in areas where chronic kidney disease (CKD) is common. However, the relationship between S. stercoralis and the gut microbiome in chronic kidney disease (CKD) is not understood fully. Recent studies have shown that gut dysbiosis plays an important role in the progression of CKD. Hence, this study aims to investigate the association of S. stercoralis infection and gut microbiome in CKD patients.

Methodology/Principal findings

Among 838 volunteers from Khon Kaen Province, northeastern Thailand, 40 subjects with CKD were enrolled and divided into two groups (S. stercoralis-infected and -uninfected) matched for age, sex and biochemical parameters. Next-generation technology was used to amplify and sequence the V3-V4 region of the 16S rRNA gene to provide a profile of the gut microbiota. Results revealed that members of the S. stercoralis-infected group had lower gut microbial diversity than was seen in the uninfected group. Interestingly, there was significantly greater representation of some pathogenic bacteria in the S. stercoralis-infected CKD group, including Escherichia-Shigella (P = 0.013), Rothia (P = 0.013) and Aggregatibacter (P = 0.03). There was also a trend towards increased Actinomyces, Streptococcus and Haemophilus (P > 0.05) in this group. On the other hand, the S. stercoralis-infected CKD group had significantly lower representation of SCFA-producing bacteria such as Anaerostipes (P = 0.01), Coprococcus_1 (0.043) and a non-significant decrease of Akkermansia, Eubacterium rectale and Eubacterium hallii (P > 0.05) relative to the uninfected group. Interesting, the genera Escherichia-Shigella and Anaerostipes exhibited opposing trends, which were significantly related to sex, age, infection status and CKD stages. The genus Escherichia-Shigella was significantly more abundant in CKD patients over the age of 65 years and infected with S. stercoralis. A correlation analysis showed inverse moderate correlation between the abundance of the genus of Escherichia-Shigella and the level of estimated glomerular filtration rate (eGFR).

Conclusions/Significance

Conclusion, the results suggest that S. stercoralis infection induced gut dysbiosis in the CKD patients, which might be involved in CKD progression.

Human strongyloidiasis is caused by a soil-transmitted helminth, Strongyloides stercoralis, which typically causes severe symptoms in immunocompromised individuals. This infection can also alter the gut microbiota and is often found in areas where chronic kidney disease (CKD) is common. However, the relationship between S. stercoralis and the gut microbiome in CKD is not known. This is the first study to investigate the gut microbiota of CKD patients with and without S. stercoralis using high-throughput sequencing of the V3–V4 region of the 16S rRNA gene. Infection with S. stercoralis was associated with reduced gut microbial diversity. In addition, infection with this nematode led to reduced abundance of SCFA-producing bacteria and enrichment of pathogenic bacteria. In particular, there were significant differences in abundance of the beneficial genus Anaerostipes (a decrease) and the pathogenic taxon Escherichia-Shigella (an increase) in CKD patients infected with S. stercoralis relative to controls. In the infected group, the representation of Escherichia-Shigella was significantly higher in patients over the age of 65 years. There was a significant inverse moderate correlation of Escherichia-Shigella with the estimated glomerular filtration rate (eGFR).

Strongyloides stercoralis hyperinfection syndrome with cerebral involvement

Strongyloidiasis is a disease caused by the intestinal helminth Strongyloides stercoralis. When the immune system of infected individuals is compromised, larvae may migrate from the gastrointestinal tract to other tissues, causing S. stercoralis hyperinfection syndrome, which has a reported mortality of 71%. In this case, we report a patient with S. stercoralis hyperinfection syndrome with central nervous system (CNS) involvement. An elderly South East Asian male tourist presented with pulmonary symptoms, fever and infiltrates on chest X-ray. He later developed symptoms of CNS infection. S. stercoralis larvae were found in a stool sample. Microbiological examination of cerebrospinal fluid revealed S. stercoralis-specific DNA. The patient was treated with oral and rectal ivermectin and albendazole. The condition was complicated by sepsis, bacteraemia and hypereosinophilia. Unfortunately, the patient eventually died from pulmonary oedema and insufficiency. This case highlights the global importance of Strongyloides CNS infection in endemic and non-endemic regions.

Strongyloidiasis Hyperinfection Syndrome in COVID-19 Positive Migrants Treated with Corticosteroids

The aim of this study is to highlight the potentially fatal risk of Strongyloidiasis Hyperinfection Syndrome for hospitalized immigrant patients with moderate to severe COVID-19 disease and undiagnosed Strongyloidiasis. We reviewed electronic medical records of immigrants from 2010 to 2022 and extracted the number of patients with eosinophilia, strongyloidiasis and COVID-19 infection, outpatient and hospitalized. While 885 outpatients were diagnosed with eosinophilia, only 356 (40.2%) were tested for strongyloidiasis and 160 (44.9%) yielded a reactive serology. COVID-19 infection was reported in 6,412 patients. 1135 (17.7%) of these patients sought hospital care. Patients with undiagnosed strongyloidiasis are at risk for a potentially fatal parasitosis if treated with systemic corticosteroids for COVID-19. This supports clinical guidelines in hospital settings for those with severe COVID-19. Strongyloidiasis should be considered by taking a thorough travel or migration history and testing before giving immunosuppressive drugs.