Human Strongyloides stercoralis infection

Strongyloides stercoralis is an important soil-transmitted helminth occurring world-wide and affecting 30-100 million people. Because many cases are asymptomatic and sensitive diagnostic methods are lacking, S. stercoralis infection is frequently underdiagnosed. The increasing incidence of autoimmune and wasting diseases and increased use of immunosuppressive agents, as well as the increased use of immunosuppressants and cytotoxic drugs, have increased S. stercoralis infection and their mortality. This review provides information about S. stercoralis epidemiology, life cycle, aetiology, pathology, comorbidities, immunology, vaccines, diagnosis, treatment, prevention, control and makes some recommendations for future prevention and control of this important parasite.

Diagnostic Approach to Pneumonia in Immunocompromised Hosts

In immunocompromised patients, pneumonia presents a diagnostic challenge due to diverse etiologies, nonspecific symptoms, overlapping radiological presentation, frequent co-infections, and the potential for rapid progression to severe disease. Thus, timely and accurate diagnosis of all pathogens is crucial. This narrative review explores the latest advancements in microbiological diagnostic techniques for pneumonia in immunocompromised patients. It covers major available microbiological tools for diagnosing both community-acquired and hospital-acquired pneumonia, encompassing a wide spectrum of pathogens including bacterial, viral, fungal, and parasitic. While traditional culture methods remain pivotal in identifying many pneumonia-causing etiologies, their limitations in sensitivity and time to results have led to the rise of non-invasive antigen tests and molecular diagnostics. These are increasingly employed alongside cultures and microscopy for more efficient diagnosis, mainly in viral and fungal infections. Lastly, we report the future of pneumonia diagnostics, exploring the potential of metagenomics and CRISPR/Cas13a for more precise and rapid pathogen detection in immunocompromised populations.

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.

Ameliorating the antiparasitic activity of the multifaceted drug ivermectin through a polymer nanocapsule formulation

Ivermectin (IVM) is a potent antiparasitic widely used in human and veterinary medicine. However, the low oral bioavailability of IVM restricts its therapeutic potential in many parasitic infections, highlighting the need for novel formulation approaches. In this study, poly(ε-caprolactone) (PCL) nanocapsules containing IVM were successfully developed using the nanoprecipitation method. Pumpkin seed oil (PSO) was used as an oily core in the developed nanocapsules. Previously, PSO was chemically analyzed by headspace solid-phase microextraction coupled to gas chromatography/mass spectrometry (HS-SPME/GC-MS). The solubility of IVM in PSO was found to be 4,266.5 ± 38.6 μg/mL. In addition, the partition coefficient of IVM in PSO/water presented a logP of 2.44. A number of nanocapsule batches were produced by factorial design resulting in an optimized formulation. Negatively charged nanocapsules measuring around 400 nm demonstrated unimodal size distribution, and presented regular spherical morphology under transmission electron microscopy. High encapsulation efficiency (98-100%) was determined by HPLC. IVM-loaded capsules were found to be stable in nanosuspensions at 4°C and 25°C, with no significant variations in particle size observed over a period of 150 days. Nanoencapsulated IVM (0.3 mM) presented reduced toxicity to J774 macrophages and L929 fibroblasts compared to free IVM. Moreover, IVM-loaded nanocapsules also demonstrated enhanced in vitro anthelmintic activity against Strongyloides venezuelensis in comparison to free IVM. Collectively, the present findings demonstrate the promising potential of PCL-PSO nanocapsules to improve the antiparasitic effects exerted by IVM.

A comparative 'omics' approach for prediction of candidate Strongyloides stercoralis diagnostic coproantigens

Human infection with the intestinal nematode Strongyloides stercoralis is persistent unless effectively treated, and potentially fatal in immunosuppressed individuals. Epidemiological data are lacking, partially due to inadequate diagnosis. A rapid antigen detection test is a priority for population surveillance, validating cure after treatment, and for screening prior to immunosuppression. We used a targeted analysis of open access 'omics' data sets and used online predictors to identify S. stercoralis proteins that are predicted to be present in infected stool, Strongyloides-specific, and antigenic. Transcriptomic data from gut and non-gut dwelling life cycle stages of S. stercoralis revealed 328 proteins that are differentially expressed. Strongyloides ratti proteomic data for excreted and secreted (E/S) proteins were matched to S. stercoralis, giving 1,057 orthologues. Five parasitism-associated protein families (SCP/TAPS, prolyl oligopeptidase, transthyretin-like, aspartic peptidase, acetylcholinesterase) were compared phylogenetically between S. stercoralis and outgroups, and proteins with least homology to the outgroups were selected. Proteins that overlapped between the transcriptomic and proteomic datasets were analysed by multiple sequence alignment, epitope prediction and 3D structure modelling to reveal S. stercoralis candidate peptide/protein coproantigens. We describe 22 candidates from seven genes, across all five protein families for further investigation as potential S. stercoralis diagnostic coproantigens, identified using open access data and freely-available protein analysis tools. This powerful approach can be applied to many parasitic infections with 'omic' data to accelerate development of specific diagnostic assays for laboratory or point-of-care field application.

A simple parasitological technique to increase detection of Strongyloides stercoralis in Bolivian primary health care system

BACKGROUND

Strongyloides stercoralis is widespread; however, there is limited information on its prevalence owing to laboratory underestimation and low clinical manifestations. The Baermann method and agar culture stand out among the parasitological techniques. Strongyloides stercoralis is present in Bolivia, but its prevalence in children remains unknown. The objective of this study was to estimate the applicability of simple parasitological techniques to increase the detection of this parasite in children living in the tropics.

METHODS

This cross-sectional study was conducted in a tropical village in Cochabamba, Bolivia. Participants were 304 children aged 5 - 12 years who provided stool samples for different parasitological analyses (direct examination, Ritchie, Baermann, and Dancescu techniques), and their parents provided informed consent.

RESULTS

Up to 64.8% of pathogenic parasites were detected using the modified Ritchie method. The Baermann technique identified 17.8% of Strongyloides stercoralis cases, and a high sensitivity with respect to the Baermann technique was only for the Dancescu technique (75.9%) that is also specific for Strongyloides stercoralis, followed by 66.7% for the modified Ritchie technique, which is used in second-line care.

DISCUSSION

The Baermann technique is the best parasitological option for improving Strongyloides stercoralis diagnosis in the first-line care of the Primary Health Care System. A particular cycle of reinfection, combined with the environment and some other risk factors are related with persistence. Control is difficult without a proper diagnosis, and the Baermann technique is an approach to the solution. We conclude that with a high suspicion of the presence of Strongyloides stercoralis, the use of the Baermann technique is strongly recommended as support for direct examination in primary health care systems especially in tropical areas.

Fatal Case of Autochthonous Strongyloides stercoralis Hyperinfection in an Immunosuppressed Calabrian Patient

Strongyloides stercoralis is an intestinal nematode that can induce disseminated infection in immunocompromised patients. It is most commonly acquired in tropical and subtropical countries; however, foci of the infection have also been reported in temperate geographic areas. In non-endemic areas, the diagnosis of an S. stercoralis infection is challenging due to the variety of clinical symptoms. Herein, we report the case of a patient, born and raised in the Calabria region of Southern Italy, who presented with melanoma and S. stercoralis hyperinfection, which is characterized by dyspnea, productive cough, inappetence, marked asthenia, weight loss, and Klebsiella pneumoniae bacteremia. He worked as a farmer and never traveled to another country known to be endemic for S. stercoralis. Despite the prompt identification of the parasite with sputum microscopy and the initiation of therapy with ivermectin and piperacillin–tazobactam, the patient later died. This case underscores the continued risk for S. stercoralis infection even in geographic areas that were previously considered non-endemic for the nematode and indicates that the geographic distribution of S. stercoralis may be expanding in Italy.

Elucidation of the inhibitory activity of ivermectin with host nuclear importin α and several SARS-CoV-2 targets

Ivermectin (IVM) is an FDA-approved drug that has shown antiviral activity against a wide variety of viruses in recent years. IVM inhibits the formation of the importin-α/β1 heterodimeric complex responsible for the translocation and replication of various viral species proteins. Also, IVM hampers SARS-CoV-2 replication in vitro; however, the molecular mechanism through which IVM inhibits SARS-CoV-2 is not well understood. Previous studies have explored the molecular mechanism through which IVM inhibits importin-α and several potential targets associated with COVID-19 by using docking approaches and MD simulations to corroborate the docked complexes. This study explores the energetic and structural properties through which IVM inhibits importin-α and five targets associated with COVID-19 by using docking and MD simulations combined with the molecular mechanics generalized Born surface area (MMGBSA) approach. Energetic and structural analysis showed that the main protease 3CLpro reached the most favorable affinity, followed by importin-α and Nsp9, which shared a similar relationship. Therefore, in vitro activity of IVM can be explained by acting as an inhibitor of importin-α, dimeric 3CLpro, and Nsp9, but mainly over dimeric 3CLpro.Communicated by Ramaswamy H. Sarma.

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.

Optimizing moxidectin dosing for Strongyloides stercoralis infections: Insights from pharmacometric modeling

Moxidectin is a frontrunner drug candidate in the treatment of strongyloidiasis. A dose of 8 mg is recommended to treat this indication, which shows a reasonably good efficacy and tolerability profile. Yet, owing to the unique life cycle of Strongyloides stercoralis (S. stercoralis) that entails internal autoinfection, a curative treatment would be desirable. Population‐based pharmacometric modeling that would help to identify an ideal dosing strategy are yet lacking. The aims of this study were to (i) explore the exposure‐efficacy response relationship of moxidectin in treating S. stercoralis and (ii) evaluate whether moxidectin treatment outcomes in terms of cure rates at baseline as compared to post‐treatment could be optimized. Our pharmacodynamic model suggests high predictive power (area under the concentration time curve‐receiver operating characteristic [AUC‐ROC] 0.817) in the probability of being cured by linking an exposure metric (i.e., AUC_0‐24 or maximum concentration [C_max]) to baseline infection intensity. Pharmacometric simulations indicate that with a minimum dose of 4 mg a maximum cure rate of ~ 95% is established in the low infection intensity group (larvae per gram [LPG] ≥0.4–1), whereas in the moderate‐to‐high intensity group (LPG >1) the cure rate plateaus at ~ 87%, following an 8 mg dose. To enhance efficacy further, studies using repeated dosing based on the duration of the autoinfection cycle, for example a two‐dose regimen 3 weeks apart should be considered. Simulations revealed similar C_max in both treatment courses of a two‐dose regimen; hence safety should not be a concern. Collectively, our results provide evidence‐based guidance for enhanced dosing strategies and should be considered when designing future treatment strategies.

The prevalence of soil transmitted helminth infections in minority indigenous populations of South-East Asia and the Western Pacific Region: A systematic review and meta-analysis

INTRODUCTION

Soil transmitted helminth (STH) infections cause one of the most prevalent diseases in man. STHs disproportionately impact socio-economically disadvantaged communities including minority indigenous populations. This systematic review aimed to quantify the prevalence of STH infection within minority indigenous populations of the South-East Asia and Western Pacific Regions.

METHODS

The systematic review was conducted in accordance with The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines following a published protocol. A random effects meta-analysis was used to estimate the pooled prevalence of STH infection, and meta-regression analysis was used to quantify associations with study characteristics. Where comparative data were available, sub-group analysis was conducted to evaluate the risk of STH infection in minority indigenous people relative to other population groups. The heterogeneity between studies was evaluated visually using Forest plots and was assessed quantitatively by the index of heterogeneity (I2) and Cochran Q-statistics.

RESULTS

From 1,366 unique studies that were identified, 81 were included in the final analysis. The pooled prevalence of infection within minority indigenous populations was 61.4% (95% CI 50.8, 71.4) for overall STH infection; 32.3% (95% CI 25.7, 39.3) for Ascaris.lumbricoides; 43.6% (95% CI 32.6, 54.8) for Trichuris.trichiura; 19.9% (95% CI 15.7, 24.5) for hookworm and 6.3% (95% CI 3.2, 10.2) for Strongyloides.stercoralis. A significant increase in T. trichiura prevalence was observed over time. The stratified analysis showed that the prevalence of infection for STH overall and for each STH species were not significantly different in minority indigenous participants compared to other populations groups.

CONCLUSION

The prevalence of STH infection is high within minority indigenous populations across countries at very different levels of socio-economic development. The increasing prevalence of T. trichiura calls for the implementation of more effective therapies and control strategies.

An in-silico analysis of ivermectin interaction with potential SARS-CoV-2 targets and host nuclear importin α

Ivermectin (IVM) is a broad-spectrum antiparasitic agent, having inhibitory potential against wide range of viral infections. It has also been found to hamper SARS-CoV-2 replication in vitro, and its precise mechanism of action against SARS-CoV-2 is yet to be understood. IVM is known to interact with host importin (IMP)α directly and averts interaction with IMPβ1, leading to the prevention of nuclear localization signal (NLS) recognition. Therefore, the current study seeks to employ molecular docking, molecular mechanics generalized Born surface area (MM-GBSA) analysis and molecular dynamics simulation studies for decrypting the binding mode, key interacting residues as well as mechanistic insights on IVM interaction with 15 potential drug targets associated with COVID-19 as well as IMPα. Among all COVID-19 targets, the non-structural protein 9 (Nsp9) exhibited the strongest affinity to IVM showing -5.30 kcal/mol and -84.85 kcal/mol binding energies estimated by AutoDock Vina and MM-GBSA, respectively. However, moderate affinity was accounted for IMPα amounting -6.9 kcal/mol and -66.04 kcal/mol. Stability of the protein-ligand complexes of Nsp9-IVM and IMPα-IVM was ascertained by 100 ns trajectory of all-atom molecular dynamics simulation. Structural conformation of protein in complex with docked IVM exhibited stable root mean square deviation while root mean square fluctuations were also found to be consistent. In silico exploration of the potential targets and their interaction profile with IVM can assist experimental studies as well as designing of COVID-19 drugs.

World Gastroenterology Organisation Global Guidelines: Management of Strongyloidiasis February 2018-Compact Version>

Strongyloides stercoralis is a soil-transmitted helminth, but it has a unique life cycle that can be completed in the human host, in a process known as autoinfection. Worldwide, the burden of disease is substantial (300 to 400 million infections). Strongyloidiasis is mainly prevalent in the tropics and subtropics, but there is as yet no global public health strategy for controlling the parasite.

Bacillus thuringiensis Cry5B is Active against Strongyloides stercoralis in vitro

Strongyloidiasis, caused by Strongyloides stercoralis infection, is an important neglected tropical disease that causes significant public health problems in the tropics and subtropics. The disease can persist in hosts for decades and may be life-threatening because of hyperinfection and dissemination. Ivermectin (mostly) and albendazole are the most common anthelmintics used for treatment. Albendazole is suboptimal for this parasite, and although ivermectin is quite effective in immunocompromised patients, a multiple-course regimen is required. Furthermore, reliance on a single drug class for treating intestinal nematodes is a recipe for future failure. Therefore, it is important to discover new anthelmintics to treat or prevent human strongyloidiasis. One promising candidate is the Bacillus thuringiensis crystal protein Cry5B. Cry5B is highly potent against parasitic nematodes, for example, hookworms and Ascaris suum. Here, we investigated the potential of Cry5B against S. stercoralis. Multiple stages of S. stercoralis, including the first larval stage (L1s), infective stage (iL3s), free-living adult stage, and parasitic female stage, were all susceptible to Cry5B as indicated by impairment of motility and decreased viability in vitro. In summary, Cry5B demonstrated strong potential as an effective anthelmintic for treatment and transmission control of human strongyloidiasis, justifying further experiments to investigate in vivo therapeutic efficacy.

Nematocidal effect of Piper retrofractum Vahl on morphology and ultrastructure of Strongyloides stercoralis third-stage infective larvae

In a previous research work aimed at discovering natural helminthicides as alternatives to conventional synthetic drugs, Piper retrofractum fruit hexane extract (PHE) has been shown to possess promising nematocidal activity against the third-stage infective larvae of Strongyloides stercoralis. Thus, this study was designed to evaluate the chemical composition and the impact of PHE on symptom and structural alterations of S. stercoralis. Chemical analysis of PHE by gas chromatography-mass spectrometry demonstrated 26 different compounds, constituting 100% of the total composition. The main components were 4-acetylphenyl (4-benzoylphenoxy) acetate (14.86%) and octyl methoxycinnamate (12.72%). Nematocidal bioassays revealed promising potential of PHE against S. stercoralis larvae, with an LC50 value of 0.059 mg/ml, while the reference drug ivermectin exerted higher efficacy, with an LC50 value of 0.020 µg/ml. Behavioural observations under light microscopy revealed that PHE-treated S. stercoralis larvae moved slowly, became paralysed and eventually died during 24 h of incubation. The dead larvae appeared under light microscope as straight worms with unknown vacuoles of different sizes inside their internal bodies. Morphological alterations of the PHE-treated S. stercoralis larvae, such as straight bodies with swollen cuticle, faded transverse annulations and faded longitudinal striations, as well as shallow and smooth lateral longitudinal grooves, were seen clearly under scanning electron microscopy. Ultrastructural changes in the treated larvae, such as protruded lateral longitudinal grooves, loose muscle with vacuolation, dissociation between the hypodermis and cuticle and marked intracellular disorganization with vacuolation, were detected under transmission electron microscopy. The results of this study provide evidence that PHE is toxic against S. stercoralis and also a potential new alternative for anti-Strongyloides chemotherapy.

Strongyloides Hyperinfection Presenting as a Gastric Outlet Obstruction

Strongyloides is a unique nematode in its ability to cause a secondary hyperinfection and disseminated disease several years following initial contact. The prevalence of Strongyloides infection has been rising; it is currently considered a global disease, which presents with a broad spectrum of clinical signs and symptoms among patients. This case report focuses on a 67-year-old Caribbean female presenting with severe weight loss, vomiting, early satiety, and mild anemia who was subsequently diagnosed with strongyloidiasis on the basis of a duodenal biopsy pathology report obtained via esophagogastroduodenoscopy (EGD).

The Anthelmintic Effect on Strongyloides venezuelensis Induced by BnSP- 6, a Lys49-phospholipase A2 Homologue from Bothrops pauloensis Venom

Background:

Phospholipases A2 (PLA2) from snake venoms have a broad potential as pharmacological tools on medicine. In this context, strongyloidiasis is a neglected parasitic disease caused by helminths of the genus Strongyloides. Currently, ivermectin is the drug of choice for treatment, however, besides its notable toxicity, therapeutic failures and cases of drug resistance have been reported. BnSP-6, from Bothorps pauloensis snake venom, is a PLA2 with depth biochemical characterization, reporting effects against tumor cells and bacteria.

Objective:

The aim of this study is to demonstrate for the first time the action of the PLA2 on Strongyloides venezuelensis.

Methods:

After 72 hours of treatment with BnSP-6 mortality of the infective larvae was assessed by motility assay. Cell and parasite viability was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Furthermore, autophagic vacuoles were labeled with Monodansylcadaverine (MDC) and nuclei of apoptotic cells were labeled with Propidium Iodide (PI). Tissue degeneration of the parasite was highlighted by Transmission Electron Microscopy (TEM).

Results:

The mortality index demonstrated that BnSP-6 abolishes the motility of the parasite. In addition, the MTT assay attested the cytotoxicity of BnSP-6 at lower concentrations when compared with ivermectin, while autophagic and apoptosis processes were confirmed. Moreover, the anthelmintic effect was demonstrated by tissue degeneration observed by TEM. Furthermore, we report that BnSP-6 showed low cytotoxicity on human intestinal cells (Caco-2).

Conclusion:

Altogether, our results shed light on the potential of BNSP-6 as an anthelmintic agent, which can lead to further investigations as a tool for pharmaceutical discoveries.

Fatal pancytopenia due to albendazole treatment for strongyloidiasis

We report 7 cases of strongyloidiasis that had occurred from 2016 through 2017 in a tertiary hospital of southern China. Three of the 7 patients (age 66-77) with farming exposure many years ago developed symptomatic infection while receiving immunosuppressant for underlying medical conditions. The majority of them were treated with albendazole due to unavailability of ivermectin in mainland China. One of the 7 patients, with underlying IgG4 sclerosing cholangitis and secondary biliary cirrhosis was on immunosuppressives and developed severe pancytopenia 15 days after albendazole treatment. He ultimately died of polymicrobial sepsis. This was the second fatal case being reported in the literature as a consequence of albendazole-induced myelosuppression. We have undertaken a review of the literature regarding the use of albendazole for strongyloidiasis and its adverse effect with a focus on myelosuppression as a rare but potentially serious event.

Strongyloidiasis Current Status with Emphasis in Diagnosis and Drug Research

Strongyloidiasis is a parasitic neglected disease caused by the nematode Strongyloides stercoralis affecting 30 to 100 million people worldwide. Complications, strongly associated with alcoholism, organ transplants, and HTLV-1 virus, often arise due to late diagnosis, frequently leading to patient death. Lack of preemptive diagnosis is not the only difficulty when dealing with this parasite, since there are no gold standard diagnostic techniques, and the ones used have problems associated with sensitivity, resulting in false negatives. Treatment is also an issue as ivermectin and benzimidazoles administration leads to inconsistent cure rates and several side effects. Researching new anti-Strongyloides drugs is a difficult task since S. stercoralis does not develop until the adult stages in Mus musculus (with the exception of SCID mice), the main experimental host model. Fortunately, alternative parasite models can be used, namely, Strongyloides ratti and S. venezuelensis. However, even with these models, there are other complications in finding new drugs, which are associated with specific in vitro assay protocol steps, such as larvae decontamination. In this review, we highlight the challenges associated with new drug search, the compounds tested, and a list of published in vitro assay methodologies. We also point out advances being made in strongyloidiasis diagnosis so far.

Type 2 Diabetes Mellitus Is Associated with Strongyloides stercoralis Treatment Failure in Australian Aboriginals

OBJECTIVE

To explore the efficacy of ivermectin in the treatment of serologically diagnosed cases of Strongyloides stercoralis (S. stercoralis) infection in an Aboriginal community and to describe factors that may influence the outcome of treatment.

METHODS

Longitudinal study of a group of 92 individuals with serologically diagnosed S. stercoralis treated with ivermectin and followed up over a period of approximately 6 months. Main outcomes were serological titers pre and post treatment, diabetic status, and duration of follow up.

FINDINGS

Treatment success was achieved in 62% to 79% of cases dependent on the methods employed for the diagnosis of infection and assessment of treatment outcome. Type 2 Diabetes Mellitus (T2DM) was found to be significantly associated with treatment failure in this group for two of the three methods employed.

INTERPRETATION

Ivermectin has been confirmed as an effective treatment for S stercoralis infection in this setting. T2DM appears to be an independent risk factor for treatment failure in this population, and plausible mechanisms to explain this observation are presented.

Strongyloides stercoralis hyperinfection associated with impaired intestinal motility disorder

Infection by Strongyloides stercoralis is a highly prevalent helminthiasis, which is mostly distributed in the tropical and subtropical regions of the world. Although a substantial number of cases are asymptomatic or paucisymtomatic, severe and life-threatening forms of this infection still occur and not infrequently is lately diagnosed. Gram-negative bacteria septicemia, which frequently accompanies the severe helminthiasis, contributes to the high mortality rate. Severe infection is invariably triggered by any imbalance in the host's immunity, favoring the auto-infective cycle, which increases the intraluminal parasite burden enormously. Clinical presentation of severe cases is varied, and diagnosis requires a high suspicion index. Acute abdomen has been reported in association with S. stercoralis infection, but intestinal necrosis is rarely found during the surgical approach. The authors report the case of a man who sought the emergency unit with recent onset abdominal pain. Clinical and imaging features were consistent with obstructive acute abdomen. Scattered adhesions and a necrotic ileal segment with a tiny perforation represented the surgical findings. The patient outcome was unfavorable and respiratory distress required an open lung biopsy. Both surgical specimens showed S. stercoralis infection. Unfortunately the patient underwent multiple organ failure and septicemia, and subsequently died. The authors call attention to the finding of intestinal necrosis and impaired intestinal motility disorder as possibilities for the diagnosis and risk factor, respectively, for a severe infection of S. stercoralis.