Clinical and Diagnostic Features of 413 Patients Treated for Imported Strongyloidiasis at the Hospital for Tropical Diseases, London

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.

Epidemiological and clinical trends of imported strongyloidiasis in a referral international health unit, Barcelona, Spain: A 12-year period experience

BACKGROUND

Imported strongyloidiasis in non-endemic countries has increasingly been diagnosed. The aim of the present study is to describe the main epidemiological and clinical characteristics of patients with imported strongyloidiasis attended in a referral International Health Unit and to detect trend changes over a 12-year period.

METHODS

This is an observational retrospective study including all imported strongyloidiasis cases seen at the International Health Unit Vall d'Hebron-Drassanes (Barcelona, Spain) from January 2009 to December 2020. Epidemiological and clinical characteristics from included patients were collected.

RESULTS

Overall, 865 cases of imported strongyloidiasis were diagnosed, of whom 472 (54.6 %) were men and mean age was 38.7 (SD 13.4) years. Most cases were diagnosed in migrants (830, 96 %). The distribution of the geographic origin was: Latin America (561, 67.6 %), Sub-Saharan Africa (148, 17.8 %), Asia (113, 13.6 %), North Africa (5, 0.6 %), Eastern Europe (2, 0.2 %), and North America (1, 0.1 %). The main reasons for consultation at the Unit were screening of health status (371, 42.9 %), laboratory test alteration (367, 42.4 %), gastrointestinal symptoms (56, 6.5 %), cutaneous symptoms (26, 3 %), and other clinical symptoms (45, 5.2 %). An increase in the number of cases was observed in the last years of the study period.

CONCLUSIONS

Imported strongyloidiasis has increasingly been diagnosed in our referral unit, mostly due to screening strategies implementation. Most of the patients were young migrants coming from Latin America, with no symptoms at the time of diagnosis. The optimization of screening strategies will increase the detection and treatment of cases, reducing potential complications.

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.

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.

Epidemiological, Clinical and Laboratory Features of Strongyloidiasis in 69 Attendees at a French Outpatient Clinic

The present retrospective study analyzed the characteristics of strongyloidiasis in patients who were diagnosed at the Outpatient Clinic of the Department of Parasitology-Mycology, Toulouse, France. Sixty-nine file records were included in the study on the basis of a positive stool examination that used Baermann's method. The prominent epidemiological findings were the presence of former immigrants from Italy or Portugal, veterans from the 1st Indochina war, and autochthonous cases. Almost 1/4 of the patients were asymptomatic. Manifestations of skin allergy were the main clinical feature. Blood eosinophilia was present in 76.8% of the patients, and serum total IgE was ≥150 kIU/L in 79.7%. Immunodiagnosis was achieved from 1990 to 2001 by indirect immunofluorescence (IFAT) that was then replaced with ELISA, both methods using Strongyloides ratti filariform larvae. ELISA was found to be similar to IFAT in terms of specificity but exhibited a greater sensitivity. Patients were primarily treated with albendazole or ivermectin beginning in 1993. Forty-eight patients attended the follow-up consultation. Kinetics of the clinical picture and blood eosinophilia were found to be the most convenient parameters to assess the efficacy of anthelmintic therapy. In conclusion, strongyloidiasis remains a neglected disease in Southwestern France. The resolution of clinical features along with the kinetics of eosinophilia appeared to be the most appropriate parameters to check during the posttreatment follow-up.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Eosinophilic Lung Diseases

The eosinophilic lung diseases may manifest as chronic eosinophilic pneumonia, acute eosinophilic pneumonia, or as the Löffler syndrome (generally of parasitic etiology). The diagnosis of eosinophilic pneumonia is made when both characteristic clinical-imaging features and alveolar eosinophilia are present. Peripheral blood eosinophils are generally markedly elevated; however, eosinophilia may be absent at presentation. Lung biopsy is not indicated except in atypical cases after multidisciplinary discussion. The inquiry to possible causes (medications, toxic drugs, exposures, and infections especially parasitic) must be meticulous. Idiopathic acute eosinophilic pneumonia may be misdiagnosed as infectious pneumonia. Extrathoracic manifestations raise the suspicion of a systemic disease especially eosinophilic granulomatosis with polyangiitis. Airflow obstruction is frequent in allergic bronchopulmonary aspergillosis, idiopathic chronic eosinophilic pneumonia, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic obliterative bronchiolitis. Corticosteroids are the cornerstone of therapy, but relapses are common. Therapies targeting interleukin 5/interleukin-5 are increasingly used in eosinophilic lung diseases.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Screening for strongyloidiasis in Spain in the context of the SARS-CoV-2 pandemic: Results of a survey on diagnosis and treatment

Introduction

The generalization of treatment with dexamethasone or other immunosuppressants in patients with SARS-CoV-2 infection may increase the risk of occurrence of severe forms of strongyloidiasis. A nationwide survey was conducted to better understand the diagnostic and therapeutic situation of strongyloidiasis in SARS-CoV-2 co-infected patients in Spain.

Materials and methods

A survey was designed and sent to all SEIMC members during February and March 2021. Responses were exported for computer processing to Microsoft Excel 2017 and statistically processed with the free software PSPP.

Results

189 responses were received, of which 121 (64%) were selected for further processing. Eighty-four centers (69.5%) had no specific strongyloidiasis screening protocol. Forty-two centers (34.7%) had serological techniques available in their laboratories and the rest were sent to a reference laboratory. Only 22 centers (18%) screened for strongyloidiasis in SARS-CoV-2 infected patients. A total of 227 cases of strongyloidiasis were diagnosed in patients with SARS-CoV-2 infection. In four cases patients developed a massive hyperinfestation syndrome leading to the death of one patient.

Conclusion

COVID-19 has highlighted the need to unify screening and treatment protocols for imported pathologies such as strongyloidiosis. Efforts to disseminate knowledge are needed to ensure that this potentially fatal disease is adequately treated in patients with the highest risk of complications, such as those with COVID-19.

Strongyloides hyper-infection in a lung transplant recipient: Case report and review of the literature

CASE PRESENTATION

A 63-year-old man with a left single lung transplant for end-stage combined restrictive and obstructive lung disease developed persistent pulmonary infiltrates and recurrent gram-negative bacteremia post-transplant. Bronchoalveolar lavage fluid revealed a nematode on Papanicolau staining compatible with Strongyloides stercoralis larvae on day 50 post-transplant. Although Strongyloides serology performed post-transplant was negative, a retrospective review of the medical record revealed marked peripheral blood eosinophilia on several occasions before transplantation. Despite reduction in immunosuppression and treatment with albendazole and ivermectin, the patient developed another episode of Escherichia coli bacteremia. He died 3 months post-transplant from pulmonary and neurological complications.

DIAGNOSIS

Strongyloides hyper-infection.

DISCUSSION

Strongyloides hyper-infection syndrome is known to occur in immunocompromised patients, but it has only been reported once in a lung transplant recipient. This case illustrates the importance of screening for parasitic infections before transplantation in patients with marked eosinophilia, especially among immigrants from countries in which Strongyloides is endemic. Hyper-infection syndrome may appear years after infection in the context of immunosuppression or immunodeficiency. This case also highlights the association between Strongyloides hyper-infection and bacteremia with enteric organisms.

Case Report: Challenges for the Diagnosis and Treatment of Strongyloides stercoralis in Chronic Obstructive Pulmonary Disease Patients

Strongyloidiasis, a neglected tropical disease (NTD), which is caused by Strongyloides stercoralis, can be fatal in immunocompromised patients. In most chronic cases, infections most frequently are asymptomatic, and eosinophilia might be the only clinical characteristic of this disease. The use of corticosteroids in some diseases like chronic obstructive pulmonary disease (COPD) may lead to the development of the life-threatening S. stercoralis hyperinfection syndrome. In the present research, we presented five cases of strongyloidiasis with a history of COPD and receiving corticosteroids from Abadan County, southwestern Iran. By performing the direct smear stool examinations, two cases were identified and the other three cases were diagnosed using the agar plate culture method. Despite reporting eosinophilia in previous patients' hospitalizations, the fecal examination was not performed for parasitic infections. Moreover, pulmonary symptoms were similar, but gastrointestinal symptoms were varied, including nausea, vomiting, abdominal pain, epigastric pain, constipation, and diarrhea. All the included patients were treated with albendazole, which is the second-line drug for S. stercoralis, and relapse of infection was observed in two patients by passing few months from the treatment. The increased blood eosinophil count was shown to play important roles in both the management of COPD and diagnosis of helminthic infections. In COPD patients who are receiving steroids, screening and follow-up for strongyloidiasis should be considered as priorities. In addition, ivermectin, which is the first-line drug for strongyloidiasis, should be available in the region.

[Screening for strongyloidiasis in Spain in the context of the SARS-CoV-2 pandemic: results of a survey on diagnosis and treatment]

Introducción

La generalización del tratamiento con dexametasona u otros inmunosupresores en pacientes con infección por SARS-CoV-2 puede aumentar el riesgo de aparición de formas graves de estrongiloidiosis. Se realizó una encuesta a nivel nacional para conocer mejor de la situación diagnóstica y terapéutica de la estrongiloidiosis en España en pacientes coinfectados por SARS-CoV-2.

Materiales y métodos

Se diseñó una encuesta que fue enviada a todos los miembros de SEIMC durante los meses de febrero y marzo de 2021. Las respuestas se exportaron para su procesamiento informático al programa Microsoft Excel 2017 y se procesaron estadísticamente con el software libre PSPP.

Resultados

Se recibieron 189 respuestas, de las cuales se seleccionaron 121 (64%) para su procesamiento posterior. En 84 centros (69,5%) no existía ningún protocolo de cribado específico de estrongiloidiosis. Cuarenta y dos centros (34,7%) disponían de técnicas serológicas en sus laboratorios y en el resto se enviaban a un laboratorio de referencia. Solo 22 centros (18%) realizaron cribado de estrongiloidiosis en pacientes infectados por SARS-CoV-2. Se diagnosticaron 227 casos de estrongiloidiosis en pacientes con infección por el SARS-CoV-2. En cuatro casos los pacientes desarrollaron un síndrome de hiperinfestación masiva que condujo al fallecimiento de uno.

Conclusión

La COVID-19 ha puesto de manifiesto la necesidad de unificar protocolos de cribado y tratamiento de patologías importadas como la estrongiloidiosis. Es necesario realizar un esfuerzo de difusión del conocimiento para que esta patología potencialmente mortal sea tratada adecuadamente en los pacientes con mayor riesgo de complicaciones, como son aquellos con COVID-19.

Clinical value of serology for the diagnosis of strongyloidiasis in travelers and migrants: A 4-year retrospective study using the Bordier IVD® Strongyloides ratti ELISA assay

Strongyloides stercoralis serology is a sensitive method for strongyloidiasis diagnosis, but it is prone to cross-reactions with other helminthiases. This four-year retrospective study aimed at estimating the performance of the Bordier IVD^®Strongyloides ratti ELISA assay in a non-endemic country (France). The study included all patients tested for strongyloidiasis in our center between 2015 and 2019, by both serology and stool examination. Cases were defined using an algorithm considering serological results, microscopic examination of stools, and other biological, clinical or epidemiological data. The study included 805 stools from 341 patients (70% migrants, 20% travelers, 10% without travel to a highly endemic area). Thirty patients (8.8%) had positive serology, 9 had microscopically proven strongyloidiasis, and 11 and 10 were classified as probable and possible strongyloidiasis, respectively. Performances of microscopy and serology were compared, considering proven and probable strongyloidiasis as true infections. The sensitivity, specificity, positive predictive value and negative predictive value of serology were 100%, 97%, 67% and 100%, respectively, and those of microscopic examination of stools were 45% (p < 0.01), 100% (p < 0.01), 100% (p = 0.079) and 96% (p < 0.001), respectively. Eosinophilia did not help in discriminating true-positive from false-positive results. Overall, these results underline the high value of the S. stercoralis serologic assay, compared to stool examination. The systematic use of this technique for screening purposes in travelers or migrants, or before onset of immunosuppressive therapy, could help to improve patient management and epidemiological knowledge.

Strongyloides-Specific IgE Phage cDNA Clones and Development of a Novel ELISA for Strongyloidiasis

Strongyloidiasis, caused mainly by the nematode Strongyloides stercoralis, is prevalent worldwide and potentially fatal in immunosuppressed patients. We report on a new IgE biomarker to diagnose Strongyloides infection. Sera from two groups infected with Strongyloides served as positive samples: Group 1A, in which infection was confirmed by stool-microscopy and/or stool-polymerase chain reaction (PCR) and was seropositive by an IgG-enzyme linked immunosorbent assay (ELISA) and an IgG4 rapid test, and Group 1B in which infection was confirmed by stool-PCR but was seronegative. Negative samples (controls) comprised infections with other parasites (Group II) and healthy donors (Group III). Immunoscreenings of an S. stercoralis complementary DNA (cDNA) library were performed, and the cDNA clone with the highest diagnostic potential (clone A133) was selected for recombinant protein production and then evaluated using IgE Western blot and ELISA. The Western blot showed that the recombinant protein (rA133) was 100% reactive with Group IA (n = 10) and Group IB (n = 5), and 96% non-reactive with Groups II and III (n = 25). Subsequently, the IgE-ELISA was developed and showed 100% diagnostic sensitivity in Groups IA (n = 32) and IB (n = 11); and 99.3% specificity in Groups II and III (n = 144). In conclusion, this study has identified rA133 as a novel recombinant protein with potential diagnostic value, and that the IgE-ELISA incorporating this protein may be useful for patient diagnosis and epidemiological studies.

Prevalence of Strongyloidiasis in a Cohort of Migrants in Italy and Accuracy of a Novel ELISA Assay for S. stercoralis Infection, a Cross-Sectional Study

Strongyloides stercoralis infection is a life-threatening neglected tropical disease. Diagnostic issues have caused an underestimation of its global burden. The choice of appropriate diagnostic tests for the screening of populations at risk of the infection, such as migrants from endemic countries, is of paramount importance. From November 2017 to July 2018, all migrants presenting to the National Institute for Health Migration and Poverty (INMP) in Rome, Italy were offered screening tests for S. stercoralis infection. The study objective was to estimate the prevalence of strongyloidiasis in the study population and the accuracy of a novel ELISA assay. The following tests were carried out at the IRCCS Sacro Cuore Don Calabria hospital in Negrar, Verona: stool microscopy, real-time PCR for S. stercoralis, in-house immunofluorescence test (IFAT), a commercial ELISA assay (Bordier ELISA), and a novel ELISA assay (Euroimmun ELISA). A latent class analysis (LCA) model set up with test results, clinical variables, and eosinophilia indicated a prevalence around 7.5%, in line with previous findings. The sensitivity and the specificity of Euroimmun ELISA were 90.6% (95% CI 80.5–100) and 87.7% (95CI 84.5–91.0); these results indicate that the novel ELISA assay would be suitable for screening of migrants from endemic countries.

Diagnostic Potential of an IgE-ELISA in Detecting Strongyloidiasis

Strongyloides stercoralis infection is prevalent worldwide and can cause lifelong infection in immunocompetent individuals, and potentially death in immunosuppressed patients. The diagnosis is hindered by the low sensitivity of microscopic examination, thus making serology an important complementary test to improve the detection rate. However, there were reports that some Strongyloides-infected individuals were negative with specific IgG and IgG4 assays, and other helminth infections were positive with commercial Strongyloides IgG-ELISAs. Thus, there is a need to develop better serodiagnostic methods for strongyloidiasis. We investigated the diagnostic potential of IgE-ELISAs using Strongyloides larval lysate. Sera from two groups infected with Strongyloides served as the positive reference, that is, 1) positive by commercial IgG-ELISAs and IgG4 rapid test, and stool samples positive by microscopy and/or PCR (group IA; n = 20); and 2) negative by IgG-ELISAs and IgG4 rapid test, but stool samples were PCR positive (group IB sera; n = 11). Sera from another two groups served as negative reference (controls), that is, 1) infected with other parasites (group II; n = 73) and 2) healthy donors (group III; n = 22). Results showed a 100% diagnostic sensitivity in detecting sera from groups IA and IB. The latter group of individuals probably had early infection because their IgG and IgG4 assays were negative. The optical density values of group IB sera were also significantly lower than those of group IA (P < 0.003). The IgE-ELISA was 100% specific when tested against sera from groups II and III. This study highlights the diagnostic potential of IgE-ELISA using larval lysate to detect strongyloidiasis, especially those with probable early infection.

High Prevalence of Strongyloides among South Asian Migrants in Primary Care-Associations with Eosinophilia and Gastrointestinal Symptoms

Gastrointestinal (GI) symptoms are a frequent reason for primary care consultation, and common amongst patients with strongyloidiasis. We conducted a prospective cohort and nested case control study in East London to examine the predictive value of a raised eosinophil count or of GI symptoms, for Strongyloides infection in South Asian migrants. We included 503 patients in the final analyses and all underwent a standardised GI symptom questionnaire, eosinophil count and Strongyloides serology testing. Positive Strongyloides serology was found in 33.6% in the eosinophilia cohort against 12.5% in the phlebotomy controls, with adjusted odds ratio of 3.54 (95% CI 1.88-6.67). In the GI symptoms cohort, 16.4% were seropositive but this was not significantly different compared with controls, nor were there associations between particular symptoms and Strongyloidiasis. Almost a third (35/115) of patients with a positive Strongyloides serology did not have eosinophilia at time of testing. Median eosinophil count declined post-treatment from 0.5 cells × 109/L (IQR 0.3-0.7) to 0.3 (0.1-0.5), p < 0.001. We conclude Strongyloides infection is common in this setting, and the true symptom burden remains unclear. Availability of ivermectin in primary care would improve access to treatment. Further work should clarify cost-effectiveness of screening strategies for Strongyloides infection in UK migrant populations.