The laboratory diagnosis and follow up of strongyloidiasis: a systematic review

Albendazole-ivermectin co-formulation for the treatment of Trichuris trichiura and other soil-transmitted helminths: a randomised phase 2/3 trial

BACKGROUND

Treatments for soil-transmitted helminthiases face challenges, especially in addressing Trichuris trichiura. Combination regimens, particularly of ivermectin and albendazole, are promising. We aimed to assess the safety, efficacy, and palatability of a combination tablet for the treatment of T trichiura, hookworm, and Strongyloides stercoralis infections among school-aged children in Ethiopia, Kenya, and Mozambique.

METHODS

We conducted an adaptive phase 2/3, randomised, parallel-group, active-controlled, superiority trial in 15 schools in Ethiopia, Kenya, and Mozambique. Eligible participants for both phases were aged 5-18 years, weighed at least 15 kg, and were infected with T trichiura, hookworms, or S stercoralis. Participants were randomly assigned via a computer-generated sequence to either a single dose of a fixed-dose combination (FDC×1) of albendazole (400 mg) plus ivermectin (9 mg or 18 mg), three consecutive daily doses of an FDC (FDC×3) of albendazole (400 mg) plus ivermectin (9 mg or 18 mg), or a single dose of albendazole alone (400 mg) via block randomisation, stratified by soil-transmitted helminth species. Participants and those administering the treatments were not masked to treatment assignment, but those assessing the outcomes were masked. The primary outcome of phase 2 (conducted in Kenya only) was safety during the first 3 h after the intervention and for 7 days, and the primary outcome of phase 3 was efficacy (ie, the proportion of individuals cured at day 21 out of the total number infected at baseline) for T trichiura; both primary outcomes were analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT05124691, and is terminated.

FINDINGS

Between Jan 20, 2022, and March 24, 2023, 1001 participants were recruited (465 [46%] were female and 536 [54%] were male). 636 (64%) were infected with T trichiura, 360 (36%) with hookworm, and 104 (10%) with S stercoralis; 94 (9%) of 1001 participants had co-infections and were included in the analysis of each infecting species. A total of 243 participants were allocated to the albendazole group, 381 to the FDC×1 group, and 377 to the FDC×3 group. In both phase 2 and 3, gastrointestinal symptoms were the most common mild-to-moderate adverse events in the FDC groups, but resolved within 48 h without intervention. At least one treatment-related adverse event occurred in 34 (14%) of 243 participants in the albendazole group, 75 (20%) of 381 participants in the FDC×1 group, and 88 (23%) of 377 participants in the FDC×3 group. No serious adverse events occurred. For T trichiura, both FDC groups had a higher cure rate (97·2% [95% CI 95·2- 99·3] for FDC×3 and 82·9% [78·2-87·5] for FDC×1) than albendazole (35·9% [27·7-44·1]), with absolute differences of 61·3% (98% CI 50·2-71·2) and 47·0% (34·7-58·1), respectively. For hookworms, FDC×3 had a higher cure rate (95·0% [95% CI 91·1-98·9]) than albendazole (65·1% [56·0-74·2]), with absolute differences of 29·9% (98% CI 17·2-42·4), whereas FDC×1 had a similar cure rate (79·8% [72·8-86·9]) to albendazole. The sample size for efficacy evaluation of S stercoralis was not met.

INTERPRETATION

An FDC of albendazole plus ivermectin has a similar safety profile but superior efficacy to albendazole alone against T trichiura infection and hookworms. These findings open opportunities for control of all soil-transmitted helminth species of interest, including potentially S stercoralis. Evaluation of safety in larger populations and implementation scenarios are the next steps for this innovation to promote its incorporation into programmatic activities.

FUNDING

European and Developing Countries Clinical Trials Partnership.

TRANSLATION

For the Portuguese translation of the abstract see Supplementary Materials section.

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.

Strongyloidiasis Treatment Outcomes: A Prospective Study Using Serological and Molecular Methods

Strongyloidiasis, caused by the soil-transmitted helminth Strongyloides stercoralis, is estimated to infect around 600 million people worldwide. Ivermectin is the current first-line treatment. This prospective study evaluated long-term treatment response in patients with chronic strongyloidiasis. Conducted from 2019 to 2022 at Vega Baja Hospital in Alicante, Spain, this study enrolled 28 patients diagnosed with S. stercoralis infection. Patients received ivermectin at a dosage of 200 mcg/kg for one or two days and were followed for at least 12 months, with evaluations at 3, 6, 12, and 18 months post-treatment. Assessments included hemogram, IgE, Strongyloides serology, larvae culture and direct visualization and Strongyloides PCR in stool. Twenty-three patients completed at least 12 months of follow-up. Twenty-one patients (91.3%) achieved treatment response. Two patients (8.6%) experienced parasitological treatment failure, with detectable Strongyloides stercoralis DNA during follow-up. Ivermectin is highly effective in treating strongyloidiasis, with serology aiding in monitoring treatment efficacy. However, PCR detected an additional case of persistent infection, underscoring its complementary role.

Respiratory Manifestations of Strongyloidiasis: Significance of Diagnosis, Treatment, and Screening

Strongyloidiasis is a widespread disease characterized clinically by acute or chronic manifestations, which, in high-risk individuals and immunocompromised individuals, can progress to hyperinfection syndrome and disseminated forms with significant mortality rates. Among extraintestinal organs, the lungs are most commonly affected. Clinical presentations are very diverse, contributing to the challenges of diagnosis and timely treatment initiation. We present the case of a 57-year-old patient who was admitted to the intensive care unit (ICU) due to bilateral pneumonia and septic shock. During a two-month hospitalization period, the patient spent 16 days on invasive mechanical ventilation. Initially, nonspecific symptoms, such as weakness, fatigue, and cough, evolved into complications, including diarrheal syndrome, hemoptysis, urticaria, and ventilator-associated pneumonia (VAP) caused by Gram-negative bacteria. Numerous larvae of Strongyloides stercoralis were identified in a stool sample. In addition to antibiotic therapy, antiparasitic treatment was administered, resulting in significant improvement in the patient's overall condition, leading to discharge for further home care. In this case, community-acquired pneumonia was complicated by the reactivation of chronic strongyloidiasis in the form of hyperinfection syndrome in a high-risk patient. High-risk individuals and immunocompromised individuals should undergo screening for parasitic infections in cases presenting with gastrointestinal symptoms, particularly diarrhea and respiratory symptoms. Screening for parasitic infections should be integrated into routine clinical practice for this population.

Molecular detection of Strongyloides stercoralis: Emerging factors and diagnostic utility

Strongyloides stercoralis infection, a neglected tropical disease, poses a significant public health threat, especially in immunocompromised individuals. This parasitic nematode can establish chronic infections, potentially progressing to life-threatening conditions such as hyperinfection syndrome and disseminated disease. Timely and accurate diagnosis is critical for effective treatment and the prevention of severe complications. Traditional diagnostic methods, such as stool microscopy, are limited by low sensitivity, particularly for detecting low-intensity infections. Advances in molecular diagnostics, particularly Polymerase Chain Reaction (PCR), have significantly improved sensitivity and specificity, marking a pivotal shift in detection capabilities. However, critical barriers persist, including inconsistencies in sample collection and handling, geographic variations in parasite strains, and the impact of genetic diversity on assay performance. Emerging molecular technologies, such as real-time PCR, loop-mediated isothermal amplification (LAMP), and droplet digital PCR (ddPCR) hold significant promise for further enhancing diagnostic precision. These advanced methods provide opportunities for more robust and accessible diagnostics, particularly in resource-limited settings. To maximize their potential, it is imperative to address existing challenges through the standardization of protocols, optimization of sample handling procedures, and the development of high-quality, reliable reagents. By overcoming these obstacles, molecular diagnostics can be more effectively integrated into clinical and public health frameworks, facilitating improved management and control of S. stercoralis infection, ultimately reducing the morbidity and mitigating the global burden of this neglected tropical disease.

Impact of intestinal parasitic infections on gut epithelial barrier and inflammation among foreign-born persons living with HIV

Systemic inflammation is a major driver of comorbidities in people with HIV (PWH). Increased levels of biomarkers of enterocyte turnover, microbial translocation, and systemic inflammation have been shown to predict morbidity and mortality in PWH on antiretroviral therapy (ART). We conducted a prospective cohort study of foreign-born PWH with undetectable HIV RNA (<20 copies/mL) with and without intestinal parasitic coinfection. Biomarkers of enterocyte turnover (intestinal fatty acid binding protein [I-FABP]), microbial translocation (soluble CD14), and systemic inflammation (soluble CD163) were measured. Stool parasite quantitative PCR (qPCR) testing and Strongyloides stercoralis recombinant IgG ELISA ( Strongy IgG) were utilized to diagnose parasitic infection. Of the 52 participants, 14 (27%) tested positive for infection with Strongyloides stercoralis by Strongy IgG, and 7 (16%) of the 45 participants who provided stool samples tested positive for a parasitic infection (not including Blastocystis ) by stool qPCR. The median sCD14 level in PWH with (+) Strongy IgG was significantly higher than PWH with (-) Strongy IgG (1.69 ug/ml versus 1.48 ug/ml, p=0.03). The median sCD163 in PWH with parasitic infections by qPCR was not significantly different from sCD163 in PWH negative for parasitic infections. I-FABP levels did not differ significantly between groups. Participants with both HIV and intestinal parasite infections had increased levels of sCD14, a marker of microbial translocation that is an independent predictor of mortality in PWH, compared to PWH without parasitic infections. These findings raise concern about the long-term sequelae of intestinal parasitic infections in PWH.

IgE and Eosinophilia in Newly Arrived Refugees in Denmark: A Cross-Sectional Study of Prevalence and Clinical Management in Primary Care

Refugees have different disease patterns than the population in receiving countries. Furthermore, refugees face barriers to accessing health care services and treatment. The purpose of this study was to describe the prevalence of eosinophilia and elevated IgE levels in refugees and assess the clinical follow-up. Using a cross-sectional study design, we offered health assessments, including eosinophil count and IgE level measurements, to all newly arrived refugees in a Danish municipality from January 2016 to November 2018. In a subgroup, we assessed the clinical follow-up. The study population consisted of 793 refugees, all of whom had eosinophil counts measured, with 411 also having IgE levels measured. Notably, 48.6% were female and most participants originated from Syria, Eritrea, Iran or Afghanistan, with smaller representation from several other countries. Notably, 6.8% had eosinophilia and 32.1% had elevated IgE levels. Syrian origin was associated with a lower prevalence of both biomarkers, and Eritrean origin with a higher prevalence. In a subgroup of 116 participants with abnormal results, general practitioners brought attention to the elevated levels in 50.9% of the cases, and 31.0% of these received a diagnosis related to the findings. In total, 98.3% (114) of patients in the subgroup had contact with their GP following the health assessment. In refugees, eosinophilia and elevated IgE levels are common conditions, and underlying causes are often not diagnosed, potentially leading to inadequate treatment and worse health outcomes.

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.

Detection of human strongyloidiasis among patients with a high risk of complications attending selected tertiary care hospitals in Colombo, Sri Lanka using molecular and serological diagnostic tools

BACKGROUND

Strongyloidiasis a neglected tropical disease is known to cause severe disease among immunosuppressed and has not been studied extensively in Sri Lanka. Parasitological diagnostic approaches based on faecal microscopy and culture often fail to detect low-intensity infections. This study investigates the presence of strongyloidiasis among selected immunocompromised individuals using parasitological, molecular and serological techniques.

METHODS

Adult patients with immunocompromising conditions admitted to three tertiary care hospitals in Sri Lanka were recruited. A faecal sample and 2 ml of venous blood were collected. The faecal samples were subjected to direct faecal smear and cultures (agar plate, charcoal and Harada-Mori) and polymerase chain reaction (PCR) using species specific primers designed for Strongyloides stercoralis. The presence of Strongyloides IgG antibodies was tested in the collected serum samples using DRG Strongyloides IgG enzyme-linked immunosorbent assay (ELISA) kits. The PCR products of the positive samples were sequenced using Sanger sequencing method.

RESULTS

A total of 260 patients were recruited to this study, out of which 160 provided faecal samples and 122 provided blood samples. Out of the 160 faecal samples, none were positive for strongyloidiasis by direct smear, charcoal and Harada-Mori cultures. Only one sample (0.6%) was positive by agar plate culture. Out of the 123 samples subjected to PCR, 14 (11.4%), including the culture positive patient, were positive for S. stercoralis. Sequencing results of the PCR products indicated 100% similarity to S. stercoralis. Out of the 122 serum samples subjected to ELISA, 20 (16.4%), including the culture positive patient, were positive for Strongyloides IgG antibodies. However, sociodemographic, exposure factors, clinical features were not significantly associated with the presence of strongyloidiasis infection.

CONCLUSIONS

Strongyloidiasis is present among the immunocompromised population in Sri Lanka, even in the absence of a significant relationship with associated factors. It is advisable to screen such patients with highly sensitive tests such as PCR for early diagnosis and treatment.

Systematic Review of Strongyloides stercoralis Infection Diagnosis in Southeast Asia: Insights from Parasitological, Molecular, and Serological Approaches

Accurate diagnosis of strongyloidiasis is crucial for effective treatment and prevention of complications. We reviewed the current landscape of diagnostic assays used in detecting Strongyloides infection in Southeast Asia. A literature search was performed using Scopus, PubMed, and Web of Science databases spanning the last three decades. Based on the exclusion and inclusion criteria, 52 papers were included in this review. We outlined the diagnostic methods used and their advantages and drawbacks. Insensitive parasitological methods were commonly used, thus underscoring the underestimation of Strongyloides infection rates in Southeast Asia. A combination of diagnostic methods (i.e., microscopy, molecular techniques, and serology) is preferred because it leads to more effective detection and higher prevalence rates. New approaches have been developed, including urine ELISAs and rapid lateral flow tests. Improving and standardizing diagnostics and making them more accessible can improve Strongyloides prevalence estimates and facilitate control efforts.

An evaluation of a lateral flow rapid diagnostic test for Strongyloides stercoralis infection

Strongyloides stercoralis in humans often presents as a chronic asymptomatic infection. Diagnosis can be challenging due to the limited sensitivity of faecal-based parasitological techniques. A prototype lateral flow rapid diagnostic test (RDT) for the detection of specific antibodies against Strongyloides stercoralis (SsRapid) was evaluated using 143 samples from the serum bank of the Swiss Tropical and Public Health Institute. Group 1 (n = 30) comprised serum samples from larvae-positive individuals; the RDT's diagnostic sensitivity was 97 % (29/30). Group II comprised serum samples from patients with other parasitic infections (n = 86) and Swiss blood donors (n = 27); the RDT's diagnostic specificity for this group was 90 % (102/113). The RDT showed good diagnostic performance and is a promising point-of-care test for detecting human Strongyloides stercoralis infection.

Effective Laboratory Diagnosis of Parasitic Infections of the Gastrointestinal Tract: Where, When, How, and What Should We Look For?

(1) Introduction: Gastrointestinal parasites (GIPs) are one of the most common causes of disease in the world. Clinical diagnosis of most parasitic diseases is difficult because they do not produce characteristic symptoms. (2) Methods: The PubMed, Science Direct, and Wiley Online Library medical databases were reviewed using the following phrases: "parasitic infections and diagnostics", "intestinal parasites", "gastrointestinal parasites", "parasitic infections and diagnostics", and their combinations. (3) Results and Conclusions: Correct diagnosis of GIP involves determining the presence of a parasite and establishing a relationship between parasite invasion and disease symptoms. The diagnostic process should consider the possibility of the coexistence of infection with several parasites at the same time. In such a situation, diagnostics should be planned with consideration of their frequency in each population and the local epidemiological situation. The importance of the proper interpretation of laboratory test results, based on good knowledge of the biology of the parasite, should be emphasized. The presence of the parasite may not be causally related to the disease symptoms. Due to wide access to laboratories, patients often decide to perform tests themselves without clinical justification. Research is carried out using various methods which are often unreliable. This review briefly covers current laboratory methods for diagnosing the most common gastrointestinal parasitic diseases in Europe. In particular, we provide useful information on the following aspects: (i) what to look for and where to look for it (suitability of feces, blood, duodenal contents, material taken from endoscopy or biopsy, tissue samples, and locations for searching for eggs, cysts, parasites, parasite genetic material, and characteristics of immune responses indicating parasitic infections); (ii) when material should be collected for diagnosis and/or to check the effectiveness of treatment; (iii) how-that is, by what methods-laboratory diagnostics should be carried out. Here, the advantages and disadvantages of direct and indirect methods of detecting parasites will be discussed. False-positive or false-negative results are a problem facing many tests. Available tests have different sensitivities and specificities. Therefore, especially in doubtful situations, tests for the presence of the pathogen should be performed using various available methods. It is important that the methods used make it possible to distinguish an active infection from a past infection. Finally, we present laboratory "case reports", in which we will discuss the diagnostic procedure that allows for the successful identification of parasites. Additionally, we briefly present the possibilities of using artificial intelligence to improve the effectiveness of diagnosing parasitic diseases.

Concomitant Serological and Molecular Methods for Strongyloides stercoralis Screening in an Endemic Area of Spain

Strongyloidiasis is a widespread parasitic disease that can be life-threatening in immunosuppressed people. In the Mediterranean basin, autochthonous cases coexist with imported ones. We aimed to assess the utility of different screening methods, along with the frequency of strongyloidiasis and its associated risk factors in migrants and the native population. This cross-sectional study took place from 2019 to 2022 in the area of the Vega Baja Hospital in Alicante, Spain. Screening was performed in people who were immunosuppressed, at risk of immunosuppression, with blood asymptomatic eosinophilia, and in asymptomatic people from highly endemic countries. Screening methods were serological techniques (ELISA), stool parasitological tests (fecal concentration methods and agar plate culture), and a stool molecular test (PCR). Of the 168 participants (62.5% males, 53.0% migrants, 36.3% immunosuppressed, median age 57 years), 14 (8.3%) had confirmed strongyloidiasis, where 6 were confirmed by serology, 4 by PCR, and 4 by both methods. Overall, 9% of the migrants and 7.6% of the native-born patients were infected. Elevated IgE and hemoglobin and Latin American origin were associated with strongyloidiasis diagnosis. Screening with serology alone would have missed 28.6% of cases. We conclude that strongyloidiasis prevalence is high in our population, both in native and migrant groups, and stool PCR is a useful tool to increase case detection.

Serological diagnosis of strongyloidiasis: An evaluation of three commercial assays

BACKGROUND

Strongyloidiasis is caused by a neglected nematode, manifesting as chronic intestinal infection with potentially severe manifestations. The disease is an emerging problem in non-endemic countries affecting travelers and migrants. Diagnosis of strongyloidiasis is hampered by the lack of standardization and absence of a gold standard. Since adequate direct methods to detect the motile larvae in stool samples are not widely available, other techniques such as serology have been developed.

METHODS

We evaluated three commercial ELISA kits (DRG Instruments, IVD Research, and Bordier Affinity Products) to detect IgG antibodies against Strongyloides stercoralis assays utilizing serum samples from travelers with microscopically confirmed strongyloidiasis (n = 50) and other imported helminthic infections (n = 159) as well as healthy controls (n = 50).

RESULTS

The DRG, IVD, and Bordier assays showed sensitivities of 58.0%, 64.0%, and 56.0%, respectively. Specificity values were 96.0%, 96.0%, and 92.0% in healthy controls, and 67.3%, 62.9%, and 76.7% in cases with other helminth infections, respectively. Cross-reactions were mostly observed in cases with other nematodes (37.5%, 42.5%, and 20.0%, respectively), but also in trematode (33.3%, 38.1%, and 19.0%, respectively) and in cestode infections (25.0%, 30.0%, and 32.5%, respectively).

CONCLUSION

The study demonstrates the diagnostic limitations of serological assays to detect or exclude cases of strongyloidiasis in returning travelers, who frequently present with recent or acute infections.

A severe case of hyperinfection by Strongyloides stercoralis in a pet dog from Romania

Strongyloides stercoralis is a zoonotic soil-transmitted nematode affecting mainly humans and dogs but identified also in non-human primates, cats and wild carnivores. It has a cosmopolitan distribution being endemic in tropical and subtropical areas. In Romania, the infection was reported on several occasions in dogs with low prevalence (3.5% -3.8%), assessed by coproscopy and it was confirmed in human patients with no travel history. A 2-year-old male Boston Terrier dog presented to a private clinic due to severe digestive problems, in July 2022. The animal had a long history of health problems. The dog was in a very bad clinical condition with severe abdominal pain, bloody diarrhea, and weight loss. Coproparasitological examinations using the saline flotation method and the modified Baermann's technique were done, both being negative. In addition, an intestinal biopsy was performed during the second endoscopy. Nematodes were collected and identified morphologically and molecularly confirmed. Histology revealed severe inflammation of the duodenal mucosa with areas of edema, necrosis, and hemorrhage, and in the intestinal glands, there were numerous nematodes suggesting a parasitic infection by Strongyloides spp. PCR followed by sequencing confirmed the infection with S. stercoralis. The dog was treated with a combination of oral fenbendazole and milbemycin oxime for 5 months. No relapse was observed 3 months after negativity was attained. This case describes a severe clinical infection by Strongyloides stercoralis in a domestic dog from Romania and the recovery after long-term treatment.

Strongyloidiasis in Auckland: A ten-year retrospective study of diagnosis, treatment and outcomes of a predominantly Polynesian and Fijian migrant cohort

BACKGROUND

Strongyloides stercoralis is not endemic in Aotearoa New Zealand (AoNZ). However, approximately one third of Auckland residents are born in endemic countries. This study aimed to describe the epidemiology and management of strongyloidiasis in Auckland, with a focus on migrants from Pacific Island Countries and Territories.

METHODS

This study retrospectively reviewed clinical, laboratory and pharmacy records data for all people diagnosed with strongyloidiasis in the Auckland region between July 2012 and June 2022. People with negative Strongyloides serology were included to estimate seropositivity rate by country of birth.

FINDINGS

Over ten years, 691 people were diagnosed with strongyloidiasis. Most diagnoses were made by serology alone (622, 90%). The median age was 63 years (range 15-92), 500 (72%) were male, and the majority were born in Polynesia (350, 51%), Fiji (130, 19%) or were of Pasifika ethnicity (an additional 7%). Twelve participants (1.7%) had severe strongyloidiasis at diagnosis. The total proportion treated with ivermectin was only 70% (484/691), with no differences between immunocompromised and immunocompetent participants, nor by ethnicity. The outcome of treatment (based on a combination of serology and/or eosinophilia and/or stool microscopy) could only be determined in 50% of the treated cohort. One participant failed treatment with ivermectin, experiencing recurrent strongyloidiasis, and another participant died in association with severe strongyloidiasis. The rate of 'positive' Strongyloides serology was highest among participants born in Samoa (48%), Fiji (39%), and Southeast Asian countries (34%).

INTERPRETATION

Strongyloidiasis was common and under-treated in Auckland during the study period. Clinicians should have a low threshold for considering strongyloidiasis in migrants from endemic countries, including Polynesia and Fiji.

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.

Strongyloidiasis

Strongyloidiasis is a neglected tropical disease caused primarily by the roundworm Strongyloides stercoralis. Strongyloidiasis is most prevalent in Southeast Asia and the Western Pacific. Although cases have been documented worldwide, global prevalence is largely unknown due to limited surveillance. Infection of the definitive human host occurs via direct skin penetration of the infective filariform larvae. Parasitic females reside in the small intestine and reproduce via parthenogenesis, where eggs hatch inside the host before rhabditiform larvae are excreted in faeces to begin the single generation free-living life cycle. Rhabditiform larvae can also develop directly into infectious filariform larvae in the gut and cause autoinfection. Although many are asymptomatic, infected individuals may report a range of non-specific gastrointestinal, respiratory or skin symptoms. Autoinfection may cause hyperinfection and disseminated strongyloidiasis in immunocompromised individuals, which is often fatal. Diagnosis requires direct examination of larvae in clinical specimens, positive serology or nucleic acid detection. However, there is a lack of standardization of techniques for all diagnostic types. Ivermectin is the treatment of choice. Control and elimination of strongyloidiasis will require a multifaceted, integrated approach, including highly sensitive and standardized diagnostics, active surveillance, health information, education and communication strategies, improved water, sanitation and hygiene, access to efficacious treatment, vaccine development and better integration and acknowledgement in current helminth control programmes.

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.

Gastrointestinal parasite infections in Nepalese Gurkha recruits arriving in the United Kingdom from 2012-2020

BACKGROUND

Gastrointestinal parasite (GIP) infections are a major cause of global morbidity, infecting hundreds of millions of people each year and potentially leading to lifelong infection and serious complications. Few data exist on screening for GIP infections in migrants entering the UK or on the current performance of different traditional diagnostic approaches. This study aimed to describe the prevalence of GIP infections in Nepalese Gurkha recruits screened on arrival in the UK.

METHODOLOGY/PRINCIPAL FINDINGS

We present a retrospective analysis of data from screening male adults (18-21 years) who arrived in the UK from Nepal between 2012 and 2020. Three separate faecal samples were obtained from participants at weekly intervals and processed for formalin-ethyl acetate (FEA) concentration/light microscopy and charcoal culture. Serum samples were analysed for IgG antibodies to Strongyloides stercoralis by ELISA. Results were available from 2,263 participants, of whom 463 (20.5%, 95% CI 18.8%-22.2%) had a positive diagnostic test for at least one GIP infection. A total of 525 potential infections were identified. Giardia duodenalis was most common (231/2263, 10.2%), followed by S. stercoralis (102/2263, 4.5%), and hookworm species (86/2263, 3.8%). Analysis (microscopy and culture) of the initial stool sample diagnosed only 244/427 (57.1%) faecally identified pathogens, including 41/86 (47.7%) hookworm infections. The proportion of participants infected with any GIP showed a downward trend over the study period. Log-binomial regression showed risk of infection decreasing by 6.1% year-on-year (95% CI 3.2% - 9.0%). This was driven predominantly by a fall in hookworm, S. stercoralis and Trichuris trichiura prevalence.

CONCLUSIONS/SIGNIFICANCE

The level of potentially pathogenic GIP infection in young Nepalese men migrating to the UK is high (20.5%) and requires a combined diagnostic approach including serology and analysis of multiple stool samples incorporating specialised parasitological methods. Advances in molecular approaches may optimise and simplify the intensive screening strategy required.

Evaluation of the accuracy of a multi-infection screening test based on a multiplex immunoassay targeting imported diseases common in migrant populations

BACKGROUND

We aimed to evaluate the performance of a novel multiplex serological assay, able to simultaneously detect IgG of six infections, as a screening tool for imported diseases in migrants.

METHODS

Six panels of 40 (n = 240) anonymized serum samples with confirmed infections were used as positive controls to assess the multiplex assay's sensitivity. One panel of 40 sera from non-infected subjects was used to estimate the seropositivity cutoffs, and 32 non-infected sera were used as negative controls to estimate each serology's sensitivity and specificity. The multi-infection screening test was validated in a prospective cohort of 48 migrants from endemic areas. The sensitivity of the Luminex assay was calculated as the proportion of positive results over all positive samples identified by reference tests. The specificity was calculated using 32 negative samples. Uncertainty was quantified with 95 % confidence intervals using receiver operating characteristic analyses.

RESULTS

The sensitivity/specificity were 100 %/100 % for HIV (gp41 antigen), 97.5 %/100 % for Hepatitis B virus (HBV-core antigen), 100 %/100 % for Hepatitis C virus (HCV-core antigen), 92.5 %/90.6 % for strongyloidiasis [31-kDa recombinant antigen (NIE)], 97.5 %/100 % for schistosomiasis (combined serpin Schistosoma mansoni and S.haematobium antigens) and 95 %/90.6 % for Chagas disease [combined Trypanosoma cruzi kinetoplastid membrane protein-11 (KMP11) and paraflagellar rod proteins 2 (PFR2) antigens]. In the migrant cohort, antibody response to the combination of the T.cruzi antigens correctly identified 100 % individuals, whereas HBV-core antigen correctly identified 91.7 % and Strongyloides-NIE antigen 86.4 %.

CONCLUSIONS

We developed a new, robust and accurate 8-plex Luminex assay that could facilitate the implementation of screening programmes targeting migrant populations.

Frequency of strongyloidiasis and associated factors: Analysis of 13 years of laboratory results in a tertiary referral hospital in Honduras, 2010-2022

INTRODUCTION

The frequency of detected strongyloidiasis is affected by the selected laboratory method in the studied population. Considering that Honduras has few community-based studies, the analysis of the laboratory record data can provide information helping to understand this parasitosis.

OBJECTIVE

To estimate the frequency and to identify the factors associated with strongyloidiasis, analyzing the laboratory records of the Servicio de Parasitología at Hospital Escuela in Tegucigalpa (Honduras) between 2010 and 2022.

MATERIALS AND METHODS

We carried out a descriptive, cross-sectional, analytical study. The laboratory diagnosis consisted of stool samples' examination by direct smear and modified Baermann technique. We estimated frequencies and percentages. The statistical association was calculated with prevalence ratios and a 95% confidence interval. Software R, version 4.2.0, and epiR package, version 2.0.46, were used to perform the analysis.

RESULTS

The frequency of strongyloidiasis was 0.29% (112/38,085). It was higher with the modified Baermann technique (0.87%; 40/4,575) among male patients (0.44%; 70/15,758). Regarding the age, strongyloidiasis was higher in the 20-40 years old group (0.41%; 28/6,886) with direct smear and 41-61 years old (1.14%; 14/1,232) group with the modified Baermann technique. Among the factors associated with strongyloidiasis were age between 20 and 61 years old (PR=2.26, CI 95%=1.53-3.31), male patients (PR=2.34, CI 95%=1.60‑3.44), mucus (PR=1.86, CI 95%=1.22-2.83) and Charcot-Leyden crystals in stool (PR=8.47, CI 95%=5.14-13.96); watery stool (PR=2.39, CI 95%=1.55-3.68), and other helminthiases (PR=6.73, CI 95%=3.98-11.38). Associated factors to cases detected with the modified Baermann technique were outpatient consultation (PR=4.21, CI 95%=1.91-9.28) and formed stools (PR=3.99, CI 95%=1.94-8.19).

CONCLUSIONS

The modified Baermann technique increased the detection of strongyloidiasis almost four times. Most cases were distributed among male adults. The cases diagnosed exclusively with the modified Baermann technique have differences from those with observed larvae in the direct smear. It is necessary to develop community-based population studies.

Prevalence of gastrointestinal parasites in captive mammals at Khon Kaen Zoo, Thailand

Background and Aim

Captive animals are susceptible to parasitic diseases due to the stress and confinement they experience. In addition, they can serve as reservoirs of zoonotic parasites that have the potential to infect humans. To investigate this possibility, we estimated the prevalence of gastrointestinal (GI) parasites in captive mammals at Khon Kaen Zoo, Thailand.

Materials and Methods

One hundred and forty-seven individual mammals (37 primates, 43 carnivores, 62 herbivores, and 5 rodents) were examined for parasitic infections by fecal examination daily for 3 consecutive days using the formalin-ethyl acetate concentration technique (FECT) and the agar plate culture method.

Results

According to FECT, the overall prevalence of GI parasites was 62.6% (92/147). Within animal groups, the numbers were as follows: 67.6% (25/37) in primates, 23.3% (10/43) in carnivores, 85.5% (53/62) in herbivores, and 80.0% (4/5) in rodents. Using the agar plate culture method, 21.43% (27/126) were positive for Strongyloides spp. and hookworm infections. The GI parasites identified belonged to three categories: protozoa (including Entamoeba histolytica species complex, Entamoeba coli, Giardia spp., coccidia, and ciliated protozoa), trematodes (minute intestinal flukes and rumen flukes), and nematodes (strongyle/hookworm, Strongyloides spp., Ascarididae, and Trichuris spp.).

Conclusion

The findings of this study indicate the prevalence of several GI parasites in zoo animals with the potential for transmission to humans, given the animals' close proximity to both visitors and animal caretakers.

Strongyloides infection screening in transplant candidates: What is the best strategy?

BACKGROUND

The potential that Strongyloides stercoralis infection has to cause major morbidity and high mortality when the disseminated form occurs in transplant patients is of particular concern.

METHODS

In this study, the objective was to observe S. stercoralis infection in patients who are candidates for transplantation by using parasitological, serological, and molecular techniques and to propose an algorithm for the detection of that infection in transplant candidates.

RESULTS

By parasitological techniques, 10% of fecal samples were positive. Anti-Strongyloides antibodies immunoglobulin G were detected in 19.3% and 20.7% of patients by immunofluorescence assay and enzyme-linked immunosorbent assay, respectively. S. stercoralis DNA was observed in 17.3% of samples by conventional polymerase chain reaction and 32.7% of samples by quantitative polymerase chain reaction (qPCR).

CONCLUSION

The set of results allows us to reinforce that a positive result by parasitological techniques and/or qPCR indicates that the specific treatment should be applied. However, the improvement of diagnostic techniques may suggest changes in the screening for strongyloidiasis in these patients.

Clinical presentation and diagnosis of imported strongyloidiasis at a tertiary hospital, Stockholm, Sweden

BACKGROUND

Since Strongyloides can persist in its host for decades, and cause life threatening infections data on prevalence, the burden and risk factors for infection is crucial in migrant populations.

METHODS

In this observational retrospective cohort study, we describe the epidemiological, clinical, and microbiological characteristics of imported strongyloidiasis diagnosed at the Karolinska University Hospital, Stockholm, Sweden, during 2010-2021.

RESULTS

We identified 98 individuals with strongyloidiasis, 89 (90.8%) born in endemic and 9 (9.2%) in non-endemic countries. Sub-Saharan Africa was the most common origin among the group born in endemic countries (62, 69.7%), (p < 0.005). There were 22 individuals with an underlying immunosuppressive condition. Gastrointestinal symptoms (53/98, 54.1%) were the symptoms most frequently described, and were more frequent in adults (57.0%) vs children (0%) (p = 0.013). Eosinophilia was detected in 74 (75.5%), being more frequent in the endemic-borne group (79.8% vs 33.3%, p = 0.002). Eight persons developed complications of strongyloidiasis because of either hyperinfection or disseminated disease. No people living with HIV with CD4 <500/mm3 (n = 6) developed severe strongyloidiasis.

CONCLUSION

A limited number of strongyloidiasis cases was identified, with few complicated cases in immunosuppressed patients. Further studies focusing on identifying and exploring the risk of complicated strongyloidiasis in immunosuppressed patients are needed.

First field study using Strong-LAMP for diagnosis of strongyloidiasis in Cubal, Angola

BACKGROUND

Strongyloides stercoralis infection is a common neglected tropical disease distributed worldwide, mainly in tropical and subtropical climates. The impact of S. stercoralis infections on human health ranges from mild asymptomatic infections to chronic strongyloidiasis unnoticeable until the host is immunosuppressed. In severe strongyloidiasis, a syndrome of hyperinfection and larval dissemination to various organs can occur with high mortality rates. The diagnosis of strongyloidiasis is challenging because of the absence of a single standard reference test with high sensitivity and specificity, which also makes it difficult to estimate the accuracy of other diagnostic tests. This study aimed to evaluate, for the first time, the use of an easy-to-perform loop-mediated isothermal amplification (LAMP) colorimetric assay (named Strong-LAMP) for the molecular screening of strongyloidiasis in stool samples from patients in a low-resource endemic area in Cubal, Angola. To compare different LAMP application scenarios, the performance of the Strong-LAMP under field conditions in Angola was reassessed in a well-equipped reference laboratory in Spain and compared with a quantitative polymerase chain reaction (qPCR) method.

METHODS

A total of 192 stool samples were collected from adult population in Cubal, Angola, and examined by parasitological methods (direct saline microscopy and Baermann's technique). DNA was extracted from each stool sample using a commercial kit and tested by the colorimetric Strong-LAMP assay for the detection of Strongyloides spp. under field conditions. Furthermore, all samples were shipped to a well-equipped laboratory in Spain, reanalysed by the same procedure and compared with a qPCR method. The overall results after testing were compared.

RESULTS

Strongyloides stercoralis larvae were identified by direct saline microscopy and Baermann in a total of 10/192 (5.2%) and 18/192 (9.4%) stool samples, respectively. Other helminth and protozoan species were also identified. The Strong-LAMP-positive results were visually detected in 69/192 (35.9%) stool samples. The comparison of Strong-LAMP results in field conditions and at a reference laboratory matched in a total of 146/192 (76.0%) samples. A total of 24/192 (12.5%) stool samples tested positive by qPCR.

CONCLUSIONS

This is the first study in which colorimetric Strong-LAMP has been clinically evaluated in a resource-poor strongyloidiasis endemic area. Strong-LAMP has been shown to be more effective in screening for strongyloidiasis than parasitological methods under field conditions and qPCR in the laboratory. Our Strong-LAMP has proven to be a field-friendly and highly accurate molecular test for the diagnosis of strongyloidiasis.

Prevalence of Strongyloides in Southeast Asia: a systematic review and meta-analysis with implications for public health and sustainable control strategies

BACKGROUND

Strongyloidiasis, caused by the nematodes Strongyloides stercoralis and Strongyloides fuelleborni, is estimated to affect over 600 million individuals worldwide. The disease is endemic in Southeast Asia, where a warm-humid climate and socio-economic conditions maintain the parasite's life cycle and transmission. However, the current diagnostic methods may not be sufficiently sensitive, suggesting that the true prevalence of strongyloidiasis could be seriously underestimated in this. This study aims to determine the prevalence of strongyloidiasis in Southeast Asia through a systematic review and meta-analysis and to discuss the implications of the estimated prevalence on diagnostic approaches and control strategies.

METHODS

Following PRISMA guidelines, we conducted a systematic literature search in PubMed and Google Scholar databases to identify studies reporting Strongyloides prevalence data in the 11 Southeast Asian countries up to December 2022. A random effects model was employed to estimate the pooled prevalence of S. stercoralis at both regional and country levels.

RESULTS

Out of 3722 articles identified, 224 met our inclusion criteria. For S. stercoralis specifically, we found 187 articles, of which 52.4% were from Thailand. All Southeast Asian countries, except Brunei, had at least one study on Strongyloides prevalence. The estimated pooled prevalence of S. stercoralis regionally was 12.7% (95% CI 10.70-14.80%), ranging from 0.4 to 24.9% at the country level. Cambodia had the highest pooled prevalence (24.9%, 95% CI 15.65-35.38%), followed by Lao PDR (16.5%, 95% CI 9.50-24.95%). Moreover, we obtained a pooled prevalence of 10% (95% CI 7.06-13.52%) in a group comprising immigrants, workers, and veterans from Southeast Asian countries. S. stercoralis infects various host types, including nonhuman primates, domestic dogs and cats, rodents, and transport carriers such as cockroaches and vegetables.

CONCLUSIONS

A high prevalence of strongyloidiasis in Southeast Asia was revealed, highlighting the importance of the region's ongoing research, surveillance, and control efforts. Factors contributing to the strongyloidiasis transmission include the role of animal hosts, the impact of global connectivity, and the significance of the co-endemicity of other Strongyloides species. Based on these findings, a multi-pronged One-Health approach is essential for sustainable intervention and control.

Multiple Stool Sampling and Specific Parasitological Technique are Crucial to Diagnose Strongyloidiasis in Alcoholic Patients

PURPOSE

Chronic alcoholism is a well-known risk factor for strongyloidiasis, in these patients the disease is potentially more severe, probably due to the breakdown of local protective barriers and immunosuppression caused by alcohol, which can lead to autoinfection and dissemination. The aim of this study was to evaluate multiple stool sampling and a specific parasitological assay agar plate culture (APC) for the diagnosis of Strongyloides stercoralis in alcoholics.

METHODS

APC was compared to sedimentation technique (HPJ; Hoffman, Pons and Janer), as parasitological methods to detect S. stercoralis infection in alcoholic individuals. Three stool samples from 60 alcoholic and 60 non-alcoholic individuals were analyzed.

RESULTS

S. stercoralis larvae were observed in 11 (18.3%) alcoholic individuals and 1 (1.7%) nonalcoholic individual (P = 0.0042). In view of the combined results, sensitivity for the APC method was 63.6% (CI 31.6-87.6%) with the first sample reaching 100% (CI 67.8-100%) after analyzing three fecal samples. The HPJ sensitivity was 36.4% (CI 12.4-68.4) in the first sample, reaching 72.7% (CI 39.3-92.7) after three samples analyzed.

CONCLUSION

The present results suggest that in alcoholic patients, it is important to repeat stool sampling with specific techniques, especially using the APC method, to avoid misdiagnosis in cases that could evolve to disseminated strongyloidiasis.

Prevalence of asymptomatic strongyloidiasis co-infection in COVID-19 patients residing in endemic areas

BACKGROUND

Fatal forms of strongyloidiasis, hyperinfection syndrome (HS) and disseminated strongyloidiasis (DS), are caused by exaggerated autoinfection of the intestinal nematode, Strongyloides stercoralis (S. stercoralis). Corticosteroids, frequently administered to patients with severe COVID-19, can transform chronic asymptomatic strongyloidiasis into the above-mentioned fatal diseases. This study aimed to investigate the prevalence of strongyloidiasis in COVID-19 patients receiving corticosteroids in a hypoendemic region.

METHODS

The present cross-sectional study enrolled 308 COVID-19 patients admitted to two hospitals in Ahvaz and Abadan in the southwest of Iran between 2020 and 2022. A real-time reverse transcription polymerase chain reaction (RT-PCR) test and chest computed tomography (CT) scan were employed to detect and monitor the disease's severity in the patients, respectively. All patients were evaluated for IgG/IgM against S. stercoralis using Enzyme-linked immunosorbent assay (ELISA) test. Subsequently, individuals with a positive ELISA test were confirmed using parasitological methods, including direct smear and agar plate culture (APC).

RESULTS

The patients were between 15 and 94 years old, with a mean age of 57.99 ± 17.4 years. Of the 308 patients, 12 (3.9%) had a positive ELISA test, while 296 (96.1%) had negative results. Three of the 12 patients with a positive ELISA result died, and three failed to provide a stool sample. To this end, only six cases were examined parasitologically, in which S. stercoralis larvae were observed in five patients. Significant differences were found between S. stercoralis infection with sex (p = 0.037) and age (p = 0.027). Binary regression analysis revealed that strongyloidiasis was positively associated with sex (odds ratio [OR]: 5.137; 95% confidence interval [CI]: 1.107-23.847), age (OR: 5.647; 95% CI 1.216-26.218), and location (OR: 3.254; 95% CI: 0.864-12.257).

CONCLUSIONS

Our findings suggest that screening for latent strongyloidiasis in COVID-19 patients in endemic areas using high-sensitivity diagnostic methods, particularly ELISA, before receiving suppressive drugs should be given more consideration.

Challenges in the diagnosis and management of IBD: a sub-Saharan African perspective

With the exception of South Africa, inflammatory bowel disease (IBD) has long been considered uncommon in sub-Saharan Africa (SSA) with a dearth of peer-reviewed publications from the subcontinent. This most likely reflects underreporting as some cases may be missed due to the high burden of infectious diseases which may closely mimic IBD. In addition, many countries in SSA have limited endoscopic capacity, inadequate access to diagnostic imaging and a notable scarcity of histopathologists, radiologists and gastroenterologists. Beyond these obstacles, which significantly impact patient care, there are many other challenges in SSA, particularly the unavailability of key IBD therapies. In this review, we discuss barriers in diagnosing and managing IBD in SSA, as well as some of the initiatives currently in place to address these short comings.

Gastroduodenal strongyloidiasis infection causing protein-losing enteropathy: A case report and review of the literature

Strongyloides stercoralis is an intestinal nematode in which adult worms in the host small intestine can cause strongyloidiasis. Symptoms in immunocompromised patients might range from diarrhea and bleeding to sepsis and even death. A 56-year-old patient presented with a 2-month history of weight loss, vomiting, and diarrhea. The patient had type 2 diabetes mellitus (T2DM) and was on long-term prednisone for chronic kidney disease. The results of the gastric emptying test and head magnetic resonance (MRI) were normal. A blood test revealed increased IgE levels, eosinophilia, and hypoalbuminemia. Parasitic larvae were not discovered during stool analysis. Gastroscopy revealed chronic nonatrophic gastritis with erosions and dilation of lymphatic vessels of the duodenum. Small-bowel capsule endoscopy suggested dilation of lymphatic vessels of the small intestine. Colonoscopy revealed no abnormalities. Finally, a histopathology examination identified S. stercoralis pervasion in the gastric antrum and duodenum. The patient was treated with albendazole and discharged successfully. In conclusion, we discovered S. stercoralis as a cause of protein-losing enteropathy in a patient with a long-term oral corticosteroid therapy and T2DM. The diagnosis was made through histopathology, once parasitological examination was negative. Therefore, health professionals should stay alert to S. stercoralis infection in immunocompromised patients with vague gastrointestinal symptoms. More sensitive methods should be applied in the diagnosis.

Spectrum of Helminth Infections in Migrants from Sub-Saharan Africa to Europe: A Literature Review

Sub-Saharan Africa (SSA) is endemic to numerous neglected tropical diseases, including many helminth diseases. With the migration of people from this part of the world to Europe, as has been happening on a large scale since 2015, these diseases are becoming more relevant to European physicians. This work aims to summarize the recent literature on this topic and to raise awareness of helminth diseases afflicting SSA migrants. The databases PubMed, Embase, and MEDLINE were screened for literature published in English and German between January 1, 2015 and December 31, 2020. In total, 74 articles were included in this review. The spectrum of helminth infections in migrants from SSA found in the literature review is broad; current research, however, is particularly focused on infections with Schistosoma spp. and Strongyloides stercoralis. Both diseases are often characterized by a long course, with few or no symptoms, with the risk of long-term organ damage. Successful and reliable screening for schistosomiasis and strongyloidiasis is strongly recommended. However, the current diagnostic methods lack sensitivity and specificity, rendering the diagnosis challenging and reliable assessment of disease prevalence difficult. Novel diagnostic methods and a greater awareness of these diseases are urgently needed.

Efficacy of Oral Ivermectin as Empirical Prophylaxis for Strongyloidiasis in Patients Treated with High-Dose Corticosteroids: A Retrospective Cohort Study

People living in areas endemic for strongyloidiasis are at risk of latent Strongyloides stercoralis infection. Corticosteroid therapy is a well-established risk factor for life-threatening hyperinfection syndrome and disseminated disease owing to suppression of the immune system. There are limited data available on the efficacy and cost of providing oral ivermectin prophylaxis to all patients receiving high-dose corticosteroids for strongyloidiasis in endemic areas. We thus conducted this retrospective cohort study at Khon Kaen University's Srinagarind Hospital from 2015 to 2019. Inclusion criteria were as follows: age ≥ 18 years, having received ≥ 0.5 mg/kg/day of prednisolone or equivalent for at least 14 days, and hospitalization during the study period. A total of 250 patients were included in the study: 125 in the empirical prophylaxis group (prescribed ivermectin even if fecal examination results were negative or nonexistent) and the remaining patients in the definite therapy group (prescribed ivermectin only if S. stercoralis was detected by fecal examination). The prevalence of strongyloidiasis at enrollment estimated by fecal examination was 5.5%. Ivermectin was given to 125 patients (100%) in the prophylaxis group compared with 12 (9.6%) in the definite therapy group (P value < 0.001). During the 12-month follow-up period, S. stercoralis was detected in three patients, two in the prophylaxis group and one in the definite therapy group (P value = 1.000). No cases of hyperinfection syndrome or disseminated disease were found. The empirical prophylaxis strategy had a significantly higher cost than the definite therapy strategy (563 versus 254, P value < 0.001) and did not demonstrate superior efficacy in strongyloidiasis prevention.

A Rare Case of Strongyloides stercoralis Hyperinfection in a Diabetic Patient from Romania-Case Report and Review of the Literature

Severe cases of strongyloidiasis are most often associated with multiple causes of immune suppression, such as corticoid treatment and HTLV (human T-lymphotropic virus) coinfection. Diabetes is not traditionally considered a risk factor for the development of severe strongyloidiasis. We report a rare case of autochthonous severe strongyloidiasis in Romania, a European country with a temperate climate. A 71-year-old patient with no prior travel history was admitted with multiple gastrointestinal complaints and recent weight loss. CT (computed tomography) scans indicated duodenal wall thickening, and duodenal endoscopy evidenced mucosal inflammation, ulcerations and partial duodenal obstruction at D4. Microscopic examination of stool samples and biopsy specimens from the gastric and duodenal mucosa revealed an increased larval burden characteristic of Strongyloides stercoralis hyperinfection. Sequential treatment with albendazole and ivermectin achieved parasitological cure and complete recovery. The novelty of our case stems from the scarcity of severe strongyloidiasis cases reported in Europe and especially in Romania, the absence of other risk factors in our patient aside from diabetes, the involvement of the gastric mucosa and the rare presentation as partial duodenal obstruction. This case highlights the importance of considering strongyloidiasis as a differential diagnosis, even in temperate climates where cases are sporadic, in cases in which immune suppression is not evident and in the absence of eosinophilia. The case is presented in the context of the first literature review examining the relationship between severe strongyloidiasis and diabetes, emphasizing diabetes as a possible risk factor for severe strongyloidiasis.

Seroprevalence of Strongyloides stercolaris in Patients about to Receive Immunosuppressive Treatment in Gran Canaria (Spain)

Strongyloides stercoralis infection is generally asymptomatic or mildly symptomatic, but in the immunosuppressed host, it is associated with more severe and complicated forms with a worse prognosis. S. stercoralis seroprevalence was studied in 256 patients before receiving immunosuppressive treatment (before kidney transplantation or starting biological treatments). As a control group, serum bank data of 642 individuals representative of the population of the Canary Islands were retrospectively analyzed. To avoid false positives due to cross-reactivity with other similar helminth antigens present in the study area, IgG antibodies to Toxocara spp. and Echinococcus spp. were evaluated in cases positive for Strongyloides. The data show this is a prevalent infection: 1.1% of the Canarian population, 2.38% of Canarian individuals awaiting organ transplants and 4.8% of individuals about to start biological agents. On the other hand, strongyloidiasis can remain asymptomatic (as observed in our study population). There are no indirect data, such as country of origin or eosinophilia, to help raise suspicion of the disease. In summary, our study suggests that screening for S. stercoralis infection should be performed in patients who receive immunosuppressive treatment for solid organ transplantation or biological agents, in line with previous publications.

Seroepidemiology of Strongyloides spp. Infection in Balimo, Western Province, Papua New Guinea

Strongyloidiasis in Papua New Guinea (PNG) is poorly understood. There have been limited surveys describing the levels of endemicity in some regions of PNG, but in the Western Province, its occurrence and level of burden are unknown. This study aimed to determine the seroepidemiology of Strongyloides spp. seropositivity within a community located in the Balimo region of the Western Province. Plasma samples were collected from 120 adult participants and were subjected to anti-IgG Strongyloides spp. serological testing. Logistical regression analyses were performed to identify relationships between strongyloidiasis and attributes of sociodemography. In this cross-sectional cohort study, 22.5% (27/120; 95% CI: 15.9-30.8%) of participants were seropositive for strongyloidiasis. Participants with higher body mass indices were less likely to be seropositive for Strongyloides spp. infection (odds ratio [OR] = 0.85, P value = 0.008), and in the multivariable analysis, increasing units of age (adjusted OR [aOR] = 0.93, P value = 0.048) and participants ≤ 40 years old were associated with a decreased likelihood of Strongyloides spp. seropositivity (aOR = 0.07, P value = 0.034). The results from this study indicate that the occurrence of strongyloidiasis is high in the Western Province, PNG, and age is a determining factor of seroreactivity. This study provides evidence of endemic strongyloidiasis in this community and raises questions as to the impact of this neglected disease and other intestinal parasites on disease burden and comorbidities.

Larva Currens: Report of Seven Cases and Literature Review

Strongyloidiasis is a frequent and often unrecognized parasitic disease because of the frequently asymptomatic nature and lack of sensitivity of diagnostic tests. Under conditions of immunosuppression (particularly systemic corticosteroid treatment), potentially fatal dissemination may occur. Thus, prevention and early diagnosis are important. Larva currens is a rare and pathognomonic cutaneous sign of strongyloidiasis, but is poorly described because of its unpredictable and fleeting occurrence. We report seven imported cases of larva currens seen in Paris between 1990 and 2020. We illustrate the clinical and biological features of this specific but uncommon sign of strongyloidiasis with clinical pictures. There were three males and four females, aged between 29 and 58 years. There were five migrants from endemic countries, one tourist and one expatriate. Digestive disorders were the main extracutaneous signs. All patients had eosinophilia above 0.5 G/L. All cases were confirmed by stool tests. All were cured with ivermectin. The rapidity and the short duration of the creeping eruption distinguish it from other parasitoses. Ivermectin is a treatment of choice. The key point is to think about preventing disseminated strongyloidiasis before giving corticosteroids not only among migrants but also among expatriates and tourists in endemic countries.

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.

Evaluation of larval surface antigens from infective larvae of Strongyloides venezuelensis for the serodiagnosis of human strongyloidiasis

Serodiagnosis of strongyloidiasis is usually performed by ELISA for the detection of IgG antibodies due to its high sensitivity and practicality, but its main limitation is a constant source of S. stercoralis antigens. The use of S. venezuelensis as a heterologous source of antigens has facilitated several published studies on the serodiagnosis and epidemiology of human strongyloidiasis. The main objective of this study was to evaluate the diagnostic accuracy of surface cuticle antigens of infective larvae of S. venezuelensis extracted with CTAB detergent (L3-CTAB) in comparison with soluble somatic extracts (L3-SSE) using a panel of sera from immunocompetent and immunocompromised individuals, at three different cut-offs. ROC curve analysis showed that L3-CTAB had an AUC of 0.9926. At the first cut-off value (OD 450 nm = 0.214), sensitivity and specificity were 100% and 90.11%, respectively, with a diagnostic accuracy of 0.93. At a second cut-off value (OD 450 nm = 0.286), sensitivity and specificity were 70% and 100%, respectively, with a diagnostic accuracy of 0.91. However, at an alternative third cut-off value (OD 450 nm = 0.589), sensitivity and specificity were 95% and 97.8%, respectively, with a diagnostic accuracy of 0.97. Using L3-CTAB as an antigenic source, the seropositivity rate in immunocompromised patients was 28.13% (9/32) whereas a seropositivity rate of 34.38% (11/32) was found when L3-SSE was used in ELISA. Therefore, the L3-CTAB is simple and practical to obtain and was found to be highly sensitive and specific.

Strongyloidiasis infection in a borderline lepromatous leprosy patient with adrenocorticoid insufficiency undergoing corticosteroid treatment: a case report

BACKGROUND

Strongyloidiasis is a soil-transmitted helminthiasis mainly caused by Strongyloides stercoralis. It is endemic to the tropics and subtropics. Sri Lanka has a 0-1.6% prevalence rate. S. stercoralis infection was identified in a 33-year-old Sri Lankan male patient treated with corticosteroids for borderline lepromatous leprosy with adrenocortical dysfunction.

CASE PRESENTATION

In March 2020, a 33-year-old Sri Lankan (Sinhalese) male patient presented with watery diarrhea, lower abdominal pain, and post-prandial abdominal fullness. Previously, he was diagnosed with borderline lepromatous leprosy and was treated with rifampicin, clofazimine, and prednisolone 60 mg daily since July 2019. After developing gastrointestinal symptoms, he had defaulted leprosy treatment including the prednisolone for 3 months. Duodenal biopsy revealed numerous intraepithelial nematodes within the lumina of glands in the duodenum whose appearance favored Strongyloides. Fecal wet smear revealed numerous Strongyloidis stercoralis L1 rhabditiform larvae. Larval tracks were seen in the agar plate culture. L3 filariform larvae of Strongyloidis stercoralis were seen in the Harada-Mori culture. In addition, the short synacthen test revealed adrenocortical insufficiency, and oral hydrocortisone and fludrocortisone were started with albendazole treatment against strongyloidiasis. Fecal wet smear and culture repeated after treatment with albendazole were negative for Strongyloidis stercoralis. The patient was discharged in July 2020 on oral hydrocortisone. One month later his condition was reviewed and the repeated fecal wet smear and agar plate culture was normal. He is being followed up every 3 months.

CONCLUSION

This is the first case of strongyloidiasis diagnosed in a patient with borderline lepromatous leprosy from Sri Lanka. The patient manifested symptoms of strongyloidiasis while on high-dose steroid therapy for his lepromatous reaction. Subsequently, the patient not only discontinued his steroid therapy, but also developed adrenocortical insufficiency as a complication of leprosy. Therefore, although diagnosis of strongyloidiasis was delayed, his subsequent low steroid levels probably protected him from disseminated disease. This is an interesting case where symptomatic strongyloidiasis was diagnosed in a patient who was initially treated with high-dose steroids but subsequently developed adrenocortical insufficiency. We emphasize the need to screen all patients prior to the commencement of immunosuppressive therapy.

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.

Improving the detection of infectious diseases in at-risk migrants with an innovative integrated multi-infection screening digital decision support tool (IS-MiHealth) in primary care: a pilot cluster-randomized-controlled trial

BACKGROUND

There are major shortfalls in the identification and screening of at-risk migrant groups. This study aims to evaluate the effectiveness of a new digital tool (IS-MiHealth) integrated into the electronic patient record system of primary care centres in detecting prevalent migrant infections. IS-MiHealth provides targeted recommendations to health professionals for screening multiple infections, including human immunodeficiency virus (HIV), hepatitis B and C, active tuberculosis (TB), Chagas disease, strongyloidiasis and schistosomiasis, based on patient characteristics (including variables of country of origin, age and sex).

METHODS

A pragmatic pilot cluster-randomized-controlled trial was deployed from March to December 2018. Eight primary care centres in Catalonia, Spain, were randomly allocated 1:1 to use of the digital tool for screening, or to routine care. The primary outcome was the monthly diagnostic yield of all aggregated infections. Intervention and control sites were compared before and after implementation with respect to their monthly diagnostic yield using regression models. This study is registered on international standard randomised controlled trial number (ISRCTN) (ISRCTN14795012).

RESULTS

A total of 15 780 migrants registered across the eight centres had at least one visit during the intervention period (March-December 2018), of which 14 598 (92.51%) fulfilled the criteria to be screened for at least one infection. There were 210 (2.57%) individuals from the intervention group with new diagnoses compared with 113 (1.49%) from the control group [odds ratio: 2.08, 95% confidence interval (CI) 1.63-2.64, P < 0.001]. The intervention centres raised their overall monthly diagnosis rate to 5.80 (95% CI 1.23-10.38, P = 0.013) extra diagnoses compared with the control centres. This monthly increase in diagnosis in intervention centres was also observed if we consider all cases together of HIV, hepatitis B and C, and active TB cases [2.72 (95% CI 0.43-5.00); P = 0.02] and was observed as well for the parasitic infections' group (Chagas disease, strongyloidiasis and schistosomiasis) 2.58 (95% CI 1.60-3.57; P < 0.001).

CONCLUSIONS

The IS-MiHealth increased screening rate and diagnostic yield for key infections in migrants in a population-based primary care setting. Further testing and development of this new tool is warranted in larger trials and in other countries.

Health and Vaccination Status of Unaccompanied Minors After Arrival in a European Border Country: A Cross-sectional Study (2017-2020)

BACKGROUND

Unaccompanied and separated children (UASC) are a high-risk group for infectious diseases and information on their vaccination status is scarce. Different approaches are used to screen newly arrived minors in Europe. The aim of this study was to describe the health status and serological protection against different vaccine-preventable diseases among UASC to inform public health decision-making.

METHODS

Retrospective study of all UASC seen at an international health reference center in Barcelona (Spain) between January 2017 and February 2020. Screening results were analyzed using binary logistic regression with adjustment for symptoms, geographic origin, and time since arrival.

RESULTS

We studied 289 UASC (88.9% males; median age, 17 years). At least one infection was diagnosed in 136 minors (47.1%). There was a high prevalence of intestinal parasites (22.8%), latent tuberculosis infection (22.5%), and hepatitis B (5.2%), even in asymptomatic individuals, and especially among UASC from sub-Saharan Africa (odds ratio, 2.5; 95% confidence interval, 1.5-4.0, P &lt; 0.001). We did not observe a significant association between clinical symptoms and the presence of infection or differences in the prevalence of different infections according to number of months since arrival. Protection against hepatitis B virus (36%), measles (80%), and varicella (83%) was suboptimal.

CONCLUSIONS

Our results highlight the importance of screening and vaccination programs for UASC arriving in Europe, especially border countries. Protocols should be adjusted according to geographic origin. Absence of symptoms does not necessarily rule out infection, highlighting the importance of screening in asymptomatic minors. These programs are a public health priority and should not be neglected during the current COVID-19 pandemic.

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.

Building an integrated serosurveillance platform to inform public health interventions: Insights from an experts' meeting on serum biomarkers

The use of biomarkers to measure immune responses in serum is crucial for understanding population-level exposure and susceptibility to human pathogens. Advances in sample collection, multiplex testing, and computational modeling are transforming serosurveillance into a powerful tool for public health program design and response to infectious threats. In July 2018, 70 scientists from 16 countries met to perform a landscape analysis of approaches that support an integrated serosurveillance platform, including the consideration of issues for successful implementation. Here, we summarize the group's insights and proposed roadmap for implementation, including objectives, technical requirements, ethical issues, logistical considerations, and monitoring and evaluation.

A systematic review and meta-analysis of human and zoonotic dog soil-transmitted helminth infections in Australian Indigenous communities

Soil-transmitted helminths (STH) infect 1.5 billion people and countless animals worldwide. In Australian Indigenous communities, STH infections have largely remained endemic despite control efforts, suggesting reservoirs of infection may exist. Dogs fulfil various important cultural, social and occupational roles in Australian Indigenous communities and are populous in these settings. Dogs may also harbour zoonotic STHs capable of producing morbidity and mortality in dogs and humans. This review provides an overview of human and zoonotic STH infections, identifies the Australian Indigenous locations affected and the parasite species and hosts involved. The meta-analysis provides estimates of individual study and pooled true prevalence of STH infections in Australian Indigenous communities and identifies knowledge gaps for further research on zoonotic or anthroponotic potential. A systematic literature search identified 45 eligible studies documenting the presence of Strongyloides stercoralis, Trichuris trichiura, Ancylostoma caninum, Ancylostoma duodenale, Ancylostoma ceylanicum, undifferentiated hookworm, and Ascaris lumbricoides. Of these studies, 26 were also eligible for inclusion in meta-analysis to establish true prevalence in the light of imperfect diagnostic test sensitivity and specificity by Rogan-Gladen and Bayesian methods. These studies revealed pooled true prevalence estimates of 18.9% (95% CI 15.8–22.1) for human and canine S. stercoralis infections and 77.3% (95% CI 63.7–91.0) for canine A. caninum infections indicating continued endemicity, but considerably more heterogenous pooled estimates for canine A. ceylanicum infections, and A. duodenale, undifferentiated hookworm and T. trichiura in humans. This review suggests that the prevalence of STHs in Australian Indigenous communities has likely been underestimated, principally based on imperfect diagnostic tests. Potential misclassification of hookworm species in humans and dogs due to outdated methodology, also obscures this picture. High-quality contemporary studies are required to establish current true prevalence of parasite species in all relevant hosts to guide future policy development and control decisions under a culturally sound One Health framework.

Soil-transmitted helminths include hookworms, threadworms, whipworms and roundworms. These worms may infect different hosts including humans and dogs, and some species are zoonotic, meaning that they are able to transmit between animals and humans. In many Australian Indigenous communities, people remain infected with these worms at high rates compared to other parts of the country despite various control strategies. Resource and health literacy inequalities are primary drivers for these differences. However, the potential for dogs to act as reservoirs for zoonotic worm infections in humans must also be considered. For this reason, it’s important to create a clear picture of the level of infection by location and host. Given that tests used to establish prevalence can produce false positive or negative results, we performed a meta-analysis allowing comparison of true prevalence estimates by location and host, regardless of the test used. This review suggests that threadworm and dog hookworm remain endemic in Australian Indigenous communities, though a gap exists to accurately inform the prevalence of the other worms. It also highlights the need for One Health strategies in research, policy and control where humans, all animal hosts and the environment are considered in a culturally relevant way.

The diagnosis of human and companion animal Strongyloides stercoralis infection: Challenges and solutions. A scoping review

Strongyloidiasis is the infection caused by soil-transmitted nematodes of Strongyloides species, infecting humans and some animals. Strongyloides stercoralis is the species with most clinical and epidemiological relevance in humans and dogs, due to its high prevalence and its capacity of inducing a life-threatening hyperinfection. Diagnosis of strongyloidiasis is challenging, due to the absence of a single reference standard test with high sensitivity and specificity, which also hampers the estimation of the accuracy of other diagnostic tests. In this chapter, we review the deployment and performance of the parasitological, immunological, molecular tests for the diagnosis of strongyloidiasis in humans and in dogs. Further, we comment the available evidence from genotyping studies that have addressed the zoonotic potential of S. stercoralis. Finally, we discuss the use of different diagnostic methods in relation to the purpose (i.e., screening, individual diagnosis, inclusion in a clinical trial) and the setting (endemic/non-endemic areas) and report the accuracy figures reported by systematic reviews on either parasitological, serological or molecular techniques published in literature.

A Rare Presentation of Strongyloides stercoralis Infection from an Immunocompetent Individual in a Tertiary Care Center in South India

Strongyloidiasis is a neglected parasitic disease caused by the intestinal parasite, Strongyloides stercoralis. Most patients with strongyloidiasis are asymptomatic, but few present with varied clinical manifestations such as cutaneous, gastrointestinal, pulmonary, and disseminated disease. It creates a diagnostic dilemma and undue delay in the diagnosis of patients. We report the case of a 79-year-old male who presented with fever and abdominal pain due to strongyloidiasis with no history of immunosuppression. The infection resolved entirely on treatment with ivermectin.

Proteomic analysis of the excretory-secretory products from Strongyloides venezuelensis infective larvae: new insights for the immunodiagnosis of human strongyloidiasis

Serodiagnosis of human strongyloidiasis is a practical alternative to parasitological methods due to its high sensitivity. However, cross-reactivity with other helminth infections limits its utility, and this problem is due to the use of homologous or heterologous somatic extracts of the parasite as an antigen source. Excretory-secretory (E/S) products from Strongyloides infective larvae can be used to improve the serodiagnosis. The combined use of western blot and proteomics became an interesting strategy to identify immunological markers for the serodiagnosis of strongyloidiasis. The present study describes the proteomic analysis of the antigenic components from E/S products of S. venezuelensis infective larvae that were recognized by IgG antibodies from patients with strongyloidiasis. Our results showed that IgG antibodies from patients with strongyloidiasis recognized between 15 and 16 antigenic bands in the E/S products from S. venezuelensis that were incubated in PBS or in RPMI culture medium, respectively. Overall, antigenic bands of low and high molecular weight were more specific than those of intermediate molecular weight, which were cross-reactive. A 36-kDa antigenic band was 93% sensitive and 100% specific (a probably arginine kinase of 37 kDa), while other antigenic bands were highly sensitive but low specific. Proteomic analysis revealed differences between the protein profiles from E/S-RPMI and E/S-PBS since only one-third of all proteins identified were common in both types of E/S products. Bioinformatic analysis showed that more than 50% of the proteins from E/S products are secreted within extracellular vesicles and only a small percentage of them are actually released by the classical secretory pathway. Several components from the E/S products were identified as plasminogen-binding proteins, probably used as an immune evasion mechanism. The data provided here provide valuable information to increase understanding of E/S products from S. venezuelensis infective larvae. This may help us to find new targets for the immunodiagnosis of human strongyloidiasis.

Current pharmacotherapeutic strategies for Strongyloidiasis and the complications in its treatment

INTRODUCTION

Strongyloidiasis, an infection caused by the soil-transmitted helminth Strongyloides stercoralis, can lead immunocompromised people to a life-threatening syndrome. We highlight here current and emerging pharmacotherapeutic strategies for strongyloidiasis and discuss treatment protocols according to patient cohort. We searched PubMed and Embase for papers published on this topic between 1990 and May 2022.

AREAS COVERED

Ivermectin is the first-line drug, with an estimated efficacy of about 86% and excellent tolerability. Albendazole has a lower efficacy, with usage advised when ivermectin is not available or not recommended. Moxidectin might be a valid alternative to ivermectin, with the advantage of being a dose-independent formulation.

EXPERT OPINION

The standard dose of ivermectin is 200 µg/kg single dose orally, but multiple doses might be needed in immunosuppressed patients. In the case of hyperinfection, repeated doses are recommended up to 2 weeks after clearance of larvae from biological fluids, with close monitoring and further dosing based on review. Subcutaneous ivermectin is used where there is impaired intestinal absorption/paralytic ileus. In pregnant or lactating women, studies have not identified increased risk with ivermectin use. However, with limited available data, a risk-benefit assessment should be considered for each case.