The changing aetiology of eosinophilia in migrants and returning travellers in the Hospital for Tropical Diseases, London 2002-2015: An observational study

Schistosomiasis in migrant children and adolescents in a paediatric tropical referral unit in Spain: diagnosis and long-term management challenges

Globalisation and population movement have led to an increasing number of migrant children residing in areas non-endemic for schistosomiasis. However, diagnosing and managing schistosomiasis in children remain controversial. This study aims to investigate the prevalence of schistosomiasis in migrant children and to describe the diagnostic approach and management strategies, including long-term follow-up, to explore the potential role of serological tests in evaluating treatment response. We conducted a retrospective descriptive study spanning from January 2014-July 2021 at a referral unit for Paediatric Tropical Diseases in Madrid (Spain). The study included patients under 18 years diagnosed with schistosomiasis. Of 679 children screened for schistosomiasis, 73 (10.8%) tested positive. The median age was 16.3 years [IQR 9-17.6], 74% male. The majority originated from Sub-Saharan Africa (47%) and Asia (47%). Only 40% presented with symptoms, with gastrointestinal (18%) and cutaneous (17%) manifestations being the most common. Eosinophilia was observed in 43% (median [IQR]: 1103/mm3 [671-1536]), and ova were visualised in the urine of 2/50 (4.0%). Praziquantel treatment was administered to 92%, and 5 patients required retreatment. Follow-up data were available for 58 (80%) over a median period of 9 months [IQR 6-19.8], revealing a progressive decline in eosinophil count, IgE titres, and ELISA optical density.    Conclusion: In this series, the prevalence of schistosomiasis among migrant children was significant (10%), highlighting the importance of including serological tests in migrant health screening. The disease is largely asymptomatic, eosinophilia is often absent, and visualisation of ova in urine is exceedingly rare. Eosinophil count, IgE titres, and ELISA optical density could prove valuable as an initial approach for monitoring inflammation during follow-up assessments. What is Known: • The burden of disease related to schistosomiasis is significant, particulary in children, and it is advisable to screen this vulnerable population. What is New: • Eosinophilia may not be present in parasitic infections, so serological tests are crucial for screening migrant children. • Serological monitoring facilitates long-term management of migrant children with schistosomiasis.

Descriptive study on risk of increased morbidity of schistosomiasis and graft loss after liver transplantation

Solid-organ transplantation procedures have witnessed a surge in frequency. Consequently, increased attention to associated infections and their impact on graft success is warranted. The liver is the principal target for infection by the flatworm Schistosoma mansoni. Hence, rigorous screening protocols for this parasite should be implemented for liver transplantation donors and recipients. This study investigated the risks posed by schistosomiasis-infected liver tissues for successful liver transplantation (LT), considering donors and recipients, by analyzing reported cases. Among the 43 patients undergoing LT (donors = 19; recipients = 24), 32 were infected with S. mansoni, five were infected with other Schistosoma species, and no identification was made in four patients. Reported follow-up periods ranged from 1 to 132 months, and all patients achieved successful recovery. As these helminths do not replicate in their vertebrate hosts, immunosuppressive treatment is not expected to promote increased morbidity or reactivation. Moreover, suspected or confirmed schistosomiasis infections often have a benign course, and generally, should not prevent LT. The available literature was reviewed and a provisional screening protocol has been proposed.

Strongyloides stercoralis infection in the UK: A systematic review and meta-analysis of published cases

Strongyloidiasis is a helminth infection where symptoms vary, and asymptomatic presentation is common. Chronic strongyloidiasis can cause a high mortality 'hyper-infection' in immunocompromised states. Understanding at risk populations and symptomology can guide screening and early treatment to reduce hyper-infection risk. A systematic review of studies describing patients in the UK with strongyloidiasis pooled a total of 1,308 patients. Weighted pooled prevalence (WPP) of asymptomatic cases was 27.7% (95% CI 17.1-39.5%, I2 = 92%, p < 0.01). At-risk populations included migrants, returning travellers and armed forces personnel. The most common symptoms reported were abdominal pain (WPP 32.1% (95% CI 20.5-44.8%), I2 = 93%, p < 0.01), rashes (WPP 38.4% (95% CI 13.1-67.7%), I2 = 99%, p < 0.01) and diarrhoea (WPP 12.6% (95% CI 6.7-19.9%), I2=70%, p = 0.03). Symptomatology varied with cohort characteristics. Although asymptomatic presentation is common, patients may present with abdominal pain, diarrhoea or rashes. A low threshold for screening symptomatic individuals in at-risk groups is required.

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.

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.

Intestinal helminthic infections: a narrative review to guide the hepatogastroenterologist

Intestinal helminthic infections are not uncommon in Western Europe, mainly due to modern travel, emigration and globalization. Moreover, some helminthic infections are endemic in Western Europe and are part of the everyday clinical practice. The hepatogastroenterologist should therefore recognize and manage these patients or at least refer them to appropriate reference centers. Signs and symptoms are often unspecific or even absent. Discerning the disease at an early stage avoids expensive diagnostic testing, life-threatening complications and in some cases even further spread of the disease. This review article aims to guide the hepatogastroenterologist when suspecting a helminthic infection by addressing the most prevalent symptoms, summarizing the most probable associated helminthic entities, highlighting practical steps in diagnosis and available treatments.

Strongyloides colitis, a rare but important mimic of Crohn's disease, resulting in coma and multi-organ failure: a case report

BACKGROUND

Strongyloides colitis is a severe form of strongyloidiasis that carries a high mortality rate if untreated. There is an overlapping clinical presentation between Strongyloides colitis and Crohn's disease. Here, we present a case of a patient who was diagnosed with Crohn's disease and was treated with immunosuppressant therapy which resulted in a poor outcome.

CASE PRESENTATION

A middle-aged, native African male presented with diarrhea, abdominal pain, and weight loss. Colonoscopy showed some patchy inflammation in the caecum, which on biopsy was suggestive of Crohn's disease. He had a short course of steroids before being admitted to an emergency with abdominal pain, diarrhea, malnutrition, and severe weight loss. Initial conservative treatment failed, and he became acutely unwell and septic with peritonitis. Laparotomy was carried out, which showed mild inflammation in the terminal ileum, which was not resected. Postoperatively, the patient became comatose and went into multi-organ dysfunction. He failed to progress, and a further laparotomy and subtotal colectomy were performed on the 12th postoperative day. His multi-organ failure progressed, and he succumbed to death 4 days later.

DISCUSSION

Strongyloides stercoralis is a parasite causing an enteric infection in animals and humans. Strongyloidiasis in immunocompetent individuals is usually an indolent disease. However, in immunocompromised individuals, it can cause hyperinfective syndrome. Patients with strongyloid colitis should undergo colonoscopy and biopsy where acute inflammation with eosinophilic infiltrates indicates parasitic infiltration of the colonic wall. Surgery is generally not indicated, and any surgical intervention with misdiagnosis of a flare-up of IBD can be very detrimental to the patient.

CONCLUSION

Strongyloid colitis can very harmfully mimic Crohn's colitis, and the use of steroids and immunosuppressants can disseminate parasitic infection. Hyperinfection syndrome can lead to sepsis, organ dysfunction, and comma. Disseminated infection carries a high mortality.

Peripheral blood eosinophilia in dogs: Prevalence and associated diseases

BACKGROUND

Canine eosinophilia has not been evaluated over the last two decades. As in human local differences, changes in the prevalence and associated diseases over time can be expected.

OBJECTIVE

This study aims to determine the prevalence and causes of marked blood eosinophilia in dogs.

METHODS

Retrospective study. A total of 317 clinical histories of dogs with an eosinophil concentration > 1.5 × 109 /L (marked eosinophilia) between 2013 and 2017 were evaluated. Patients were allocated to 10 groups according to their major clinical findings.

RESULTS

Eosinophilia was present in 1,592 of 10,829 dogs (14.7%); it was mild (0.8-1.49 × 109 /L) in 78.4%, moderate (1.5 - 4.9 × 109 /L) in 20.5% and severe (> 5 × 109 /L) in 1.1% of cases. Rottweilers were overrepresented (16.1%). Of 317 cases with marked eosinophilia, 19.6% had neoplasia, 19.1% gastrointestinal disorders, 13.6% health check, 10.4% endoparasites, 6% respiratory, 5.4% neurologic, 5.4% dermatologic, 4.8% urogenital, 3.2% endocrine disorders and 12.6% miscellaneous. Lymphomas (29%) and mast cell tumours (12.9%) were the most frequent tumours in the neoplasia group. A total of 72.6% of tumour-bearing dogs were older than 8 years, while 63.6% of dogs had endoparasites, and 86% of apparently healthy dogs were younger than 5 years. Eosinophilia was significantly higher in patients with respiratory disorders (p < 0.0146). Leukocytosis was found in 50.2% of cases.

CONCLUSION

Malignancy was the most common cause of marked blood eosinophilia in older dogs and endoparasitism in younger dogs. Eosinophilia was common in apparently healthy young dogs and may be related to undiagnosed parasitic infestations.

Eosinophilia in Migrant Children: How Should We Proceed?

BACKGROUND

The diagnostic approach to eosinophilia is complex, given the numerous reported etiologies. Intestinal parasites (especially helminths) are a concern in children from high-burden settings. We describe the diagnostic approach and clinical management of eosinophilia in a cohort of migrant children.

METHODS

We conducted a retrospective observational study that included children diagnosed with eosinophilia at a reference center for pediatric tropical diseases from 2014 to 2018. All patients were screened according to a unified protocol, including direct microbiologic and serologic tests.

RESULTS

A total of 163 children presented with eosinophilia during the study period [median age, 7.7 years (4.1-12.2); 57.1% boys], mostly from Asia (27.6%) and South America (22.1%). Most were internationally adopted children (43.6%) or migrants (26.4%). Only 34.4% of the children were symptomatic, and the main etiology for eosinophilia was helminths (56.4%). After a sequential diagnostic approach, no etiology was found for 40.5% of the patients. The independent risk factors for an unexplained etiology were younger age (≤2 years: odds ratio, 3.6; 95% CI, 1.3-10.2; P = 0.015), absence of symptoms (odds ratio, 4.8; 95% CI, 1.8-12.5; P = 0.001) and mild eosinophilia (<1000/µL: odds ratio, 4.2; 95% CI, 4.5-11.7; P = 0.005). Only 6 children were treated empirically. In those children with an identified cause and in those treated empirically, the eosinophilia resolved in 52% in a median of 7 months (5-9).

CONCLUSIONS

Helminths are the main cause of eosinophilia in migrant children and need to be hunted, especially in older children with eosinophil counts >1000 eosinophils/µL.

Image challenge: Beware of diagnostic anchoring - An offshore vessel welding inspector with eosinophilia and a cough productive of 'worms'

A 38-year old male was referred from an Acute Medical Unit to a regional Tropical Infectious Disease Unit with a seven-week history of dyspnoea, wheeze and cough reportedly productive of worms. The patient had taken photographs of the expectorated substance which allowed macroscopic examination by a consultant in infectious diseases. Fresh samples were also sent for histological examination. Initial investigations showed a prominent eosinophilia of 2.5 × 10⁹/ml (0.0-0.4 × 10⁹/ml).

Screening for infection in unaccompanied asylum-seeking children and young people

We aimed to evaluate a screening programme for infection in unaccompanied asylum seeking children and young people against national guidance and to described the rates of identified infection in the cohort. The audit was conducted by retrospective case note review of routinely collected, anonymised patient data from all UASC referred between January 2016 and December 2018 in two paediatric infectious diseases clinics.There were 252 individuals from 19 countries included in the study, of these 88% were male, and the median age was 17 years (range 11-18). Individuals from Afghanistan, Eritrea and Albania constituted the majority of those seen. Median time between arriving in the UK and infection screening was 6 months (IQR 4-10 months, data available on 197 UASC). There were 94% (238/252) of cases tested for tuberculosis (TB), of whom 23% (55/238) were positive, including three young people with TB disease. Of those tested for hepatitis B, 4.8% (10/210) were positive, 0.5% (1/121) were positive for hepatitis C and of 252 tested, none were positive for HIV. Of the 163 individuals who were tested for schistosomiasis, 27 were positive (16%).The majority of patients were appropriately tested for infections with a high rate of identification of treatable asymptomatic infection. Infections were of both individual and public health significance. Our findings of clinically significant rates of treatable infections in UASC highlight the importance of infection screening for all in this vulnerable patient group.

First international external quality assessment scheme of nucleic acid amplification tests for the detection of Schistosoma and soil-transmitted helminths, including Strongyloides: A pilot study

BACKGROUND

Nucleic acid amplification tests (NAATs) are increasingly being used as diagnostic tools for soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Ancylostoma duodenale and A. ceylanicum), Strongyloides stercoralis and Schistosoma in human stool. Currently, there is a large diversity of NAATs being applied, but an external quality assessment scheme (EQAS) for these diagnostics is lacking. An EQAS involves a blinded process where test results reported by a laboratory are compared to those reported by reference or expert laboratories, allowing for an objective assessment of the diagnostic performance of a laboratory. In the current study, we piloted an international EQAS for these helminths (i) to investigate the feasibility of designing and delivering an EQAS; (ii) to assess the diagnostic performance of laboratories; and (iii) to gain insights into the different NAAT protocols used.

METHODS AND PRINCIPAL FINDINGS

A panel of twelve stool samples and eight DNA samples was validated by six expert laboratories for the presence of six helminths (Ascaris, Trichuris, N. americanus, Ancylostoma, Strongyloides and Schistosoma). Subsequently this panel was sent to 15 globally dispersed laboratories. We found a high degree of diversity among the different DNA extraction and NAAT protocols. Although most laboratories performed well, we could clearly identify the laboratories that were poorly performing.

CONCLUSIONS/SIGNIFICANCE

We showed the technical feasibility of an international EQAS for the NAAT of STHs, Strongyloides and Schistosoma. In addition, we documented that there are clear benefits for participating laboratories, as they can confirm and/or improve the diagnostic performance of their NAATs. Further research should aim to identify factors that explain poor performance of NAATs.

Soil-transmitted helminthiases in Nepal: Transmission boundaries and implications for local communities and international travelers

Soil transmitted helminthiasis (STHs) are endemic in Nepal but since the country territory is extremely heterogeneous, a multidisciplinary assessment is required to evaluate the risk of infection in different areas. Prevalence data were retrieved with systematic literature search and geographical coordinates were assigned to each survey site. Spatial stratification was then implemented considering land use and ecological parameters. STH transmission boundaries were tested after reference criteria and elevation was evaluated as additional predictor: the elevation threshold of 3057 m above sea level is demarking the STH transmission limit. Areas above this threshold are safe, but since lodging in at-risk sites is a compulsory stopover for international travelers, STH risk exposure should be considered for every travel to the country.

Strongyloides stercoralis infection: A systematic review of endemic cases in Spain

BACKGROUND

Strongyloides stercoralis infection, a neglected tropical disease, is widely distributed. Autochthonous cases have been described in Spain, probably infected long time ago. In recent years the number of diagnosed cases has increased due to the growing number of immigrants, travelers and refugees, but endemically acquired cases in Spain remains undetermined.

METHODOLOGY

We systematically searched the literature for references on endemic strongyloidiasis cases in Spain. The articles were required to describe Strongyloides stercoralis infection in at least one Spanish-born person without a history of travel to endemic areas and be published before 31st May 2018. Epidemiological data from patients was collected and described individually as well as risk factors to acquisition of the infection, diagnostic technique that lead to the diagnosis, presence of eosinophilia and clinical symptoms at diagnosis.

FINDINGS

Thirty-six studies were included, describing a total of 1083 patients with an average age of 68.3 years diagnosed with endemic strongyloidiasis in Spain. The vast majority of the cases were described in the province of Valencia (n = 1049). Two hundred and eight of the 251 (82.9%) patients in whom gender was reported were male, and most of them had current or past dedication to agriculture. Seventy percent had some kind of comorbidity. A decreasing trend in the diagnosed cases per year is observed from the end of last decade. However, there are still nefigw diagnoses of autochthonous cases of strongyloidiasis in Spain every year.

CONCLUSIONS

With the data provided by this review it is likely that in Spain strongyloidiasis might have been underestimated. It is highly probable that the infection remains undiagnosed in many cases due to low clinical suspicion among Spanish population without recent travel history in which the contagion probably took place decades ago.