Schistosomiasis In Travellers Research Articles

Imported schistosomiasis in travelers: Experience from a referral tropical medicine unit in Barcelona, Spain

BackgroundAcute schistosomiasis occurs most often in travelers to endemic regions. The aim of the study is to describe the epidemiological, clinical and parasitological characteristics of patients with schistosomiasis acquired during an international travel. MethodsObservational retrospective study including all travel-related schistosomiasis cases seen at the International Health Unit Vall d’Hebron-Drassanes (Barcelona, Spain) from 2009 to 2022. Diagnosis of schistosomiasis was defined by the presence of Schistosoma eggs in stools or urine or the positivity of a serological test. We collected demographic, epidemiological, clinical, parasitological, and therapeutic information. Results917 cases of schistosomiasis were diagnosed, from whom 96 (10.5 %) were travel-related. Mean age of the patients was 34.9 years, and 53.1 % were women. Median duration of the travel was 72 days, and geographical areas where travelers had contact with fresh water were Africa (82.3 %), Asia (12.5 %), and South America (5.2 %). Twenty (20.8 %) patients reported having had some clinical symptom, being gastrointestinal symptoms the most frequent. Two patients developed the classical Katayama syndrome. In eleven (11.5 %) cases eggs were observed in urine or feces samples, and 85 (88.5 %) cases were diagnosed by a positive serology. Ninety-one (94.8 %) patients received treatment with praziquantel with different therapeutic schemes. The two patients with Katayama syndrome received concomitant treatment with corticosteroids. ConclusionsSchistosomiasis in travelers represented 10 % of the overall schistosomiasis cases in our center. Increasing the awareness in the pre-travel advice and implementing specific screening in those travelers at risk (long travelers, contact with fresh water) could reduce the incidence and associated morbidity in this group.

Unusual and Severe Complications of Acute Schistosomiasis in Travelers.

Acute schistosomiasis (ASC) is a hypersensitivity reaction seen mostly in nonimmune travelers and manifests mainly with fever, urticaria, and respiratory symptoms. We describe unusual severe presentations of ASC in 3 patients, including hip-monoarthritis, peri-myocarditis, and optic neuritis. In all 3 patients, clinical symptoms appeared or worsened after praziquantel administration.

Evaluation of a duplex real-time PCR in human serum for simultaneous detection and differentiation of Schistosoma mansoni and Schistosoma haematobium infections – cross-sectional study

BackgroundWe evaluated a one-tube multiplex real-time PCR targeting DNA of Schistosoma haematobium complex and S. mansoni complex in serum samples obtained at different German diagnostic centers. MethodsSimplex real-time PCR protocols for the detection of the multi-copy DNA-repeats Dra1 of S. haematobium complex and Sm1-7 of S. mansoni complex in serum were combined to a new one-tube multiplex format. The new PCR was subjected to full validation including evaluation in a diagnostic real-life setting with travelers and migrants. PCR results were compared with those of stool and urine microscopy, serology, and circulating cathodic antigen (CCA) rapid diagnostic tests in urine. Sensitivity and specificity of the diagnostic approaches were analyzed using latent class analysis (LCA). ResultsLCA assessment indicated sensitivity and specificity of 94.9% and 98.4%, respectively, for serum PCR if serology was included in the calculation, and 100% and 95.6%, respectively, if serology was not included as a parameter not necessarily associated with active infection. Agreement between the compared diagnostic procedures at genus level was fair (kappa 0.273) if serology was included and moderate (kappa 0.420) if serology was not included. DiscussionThe PCR assay proved to be highly reliable for the diagnosis of schistosomiasis in travelers and migrants.

Schistosomiasis in Norwegian students after travel to Africa.

Schistosomiasis is a tropical infectious disease in which early diagnosis and treatment can prevent serious illness. This study examined the incidence and diagnosis of schistosomiasis in Norwegian exchange students who had been exposed to freshwater in Africa. Students (n = 318) from Bergen and Oslo who had travelled to Africa as part of an exchange programme in the period 2003-18, were contacted and included in the study if they had been exposed to freshwater during their stay. A routine workup was performed comprising Schistosoma antibody testing, microscopy and/or PCR analysis of urine and faeces, dipstick urinalysis, and blood samples for analysis of eosinophilic granulocytes, creatinine and total IgE. Time, place and type of exposure were recorded in a questionnaire, along with symptoms. Schistosoma antibodies were detected in 46 (30%) of the 151 students included in the study. None of the seropositive individuals had eggs detected in their urine or faeces, and none had eosinophilia. Two students reported cercarial dermatitis, while one had symptoms consistent with acute schistosomiasis. Rafting was the only form of freshwater exposure reported by 22 (55%) of the 40 seropositive individuals. A large proportion of the students who had been exposed to freshwater were diagnosed with schistosomiasis. The majority reported no symptoms. Rafting was the most common form of exposure. All were diagnosed by serologic tests, while other routine diagnostic tests for schistosomiasis proved less useful. Serological analysis should be the preferred form of testing for the diagnosis of schistosomiasis in travellers.

Acute Schistosomiasis in European Students Returning From Fieldwork at Lake Tanganyika, Tanzania: Table 1

Schistosomiasis is common in many African regions and poses a risk for travelers and the local population. So far, schistosomiasis in travelers or expatriates returning from the Tanzanian bank of Lake Tanganyika has not been reported. We report a group of students who sought treatment with signs of acute schistosomiasis after having returned from Lake Tanganyika, Tanzania. Information as to travel and exposure as well as clinical and laboratory data were collected. Schistosomiasis was diagnosed in 8 of 16 students from Berlin, Germany, who had returned from a 2- to 3-month stay of fieldwork in Kigoma District at Lake Tanganyika, Tanzania. All 16 students reported frequent freshwater exposure at the lake. Six patients showed signs of acute schistosomiasis and had fever, and some of them also had cough, weakness, headache, or abdominal pain. Eosinophilia was present in five of the six symptomatic individuals. Notably, two serologically enzyme-linked immunosorbent assay (ELISA)-positive individuals did not report or present with symptoms or abnormal laboratory parameters. Schistosoma mansoni eggs were found in one symptomatic and one asymptomatic individual each. Blood and stool samples from the other eight individuals who were equally exposed to freshwater yielded negative results. This is the first report of an outbreak of acute schistosomiasis imported from the Tanzanian shore of Lake Tanganyika and highlights the risk for travelers and the local population of acquiring the infection in that part of Tanzania. It provides arguments for routine serological screening for schistosomiasis in individuals who had prior freshwater contact in endemic areas, irrespective of symptoms or other laboratory findings.

High Rate of Schistosomiasis in Travelers After a Brief Exposure to the High-Altitude Nyinambuga Crater Lake, Uganda

Travel-related schistosomiasis is usually associated with prolonged freshwater exposure. Until recently, Uganda's crater lakes were considered schistosomiasis free due to their high-altitude location. We describe an outbreak of acute schistosomiasis after a brief exposure (mean, 22 ± 9.5 minutes) to a high-altitude crater lake.

An Interesting Cause of Rectal Bleeding in an African Immigrant

Question: A 30-year-old Sudanese-born man who emigrated to the United States 10 years ago with a past medical history of hepatitis B as well as recently treated Helicobacter pylori gastritis presented for outpatient follow-up for management of hepatitis B. His previous symptoms of heartburn and dyspepsia had improved with treatment of H pylori. He now complained of rectal bleeding with anal pruritus. He had no recent travel, no sick contacts, and had not started any new medications. On physical examination, he was afebrile with stable vital signs. He seemed well nourished. He had no scleral icterus. His abdominal examination was benign. He had no rash or jaundice. Rectal examination revealed no abnormalities. Complete blood count with differential revealed a white blood count of 3.1 K/μL with 6.1% eosinophils. Chemistry was normal. Liver function tests were unremarkable other than a stable total bilirubin of 1.8 g/dL. A flexible sigmoidoscopy (Figure A) was performed which revealed erythematous mucosa in the sigmoid colon, which was biopsied for pathologic examination (Figure B and C). What is the diagnosis? How should this patient be treated? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Tissue biopsy confirmed colonic mucosa with parasitic egg forms with granulomatous and eosinophilic response, concerning for Schistosoma mansoni. The patient was treated with praziquantel and had improvement in symptoms. Schistosomiasis is caused by a parasite that uses snails as intermediate hosts and humans as definitive hosts. It is endemic in parts of Africa, the Middle East, and Asia. Humans are infected through skin penetration in freshwater containing larvae. Most patients infected are asymptomatic. Acute infection in travelers can cause a localized dermatitis called “swimmer's itch” and a hypersensitivity syndrome known as Katayama fever. Those with this syndrome tend to present with symptoms similar to serum sickness and findings of lymphadenopathy and hepatosplenomegaly. Chronic manifestations in those living in endemic areas result from a granulomatous response to egg trapping in various organ systems, including the intestines, liver, bladder, and central nervous system. Examination of urine or feces for egg forms is the gold standard for diagnosis of active infection. Tissue biopsy may be required for diagnosis. Infected patients should be treated with praziquantel. Glucocorticoids should be used in patients with suspected Katayama fever and those with neurologic involvement. After treatment, urine or stool specimens should be assessed for cure.1Clerinx J. Van Gompel A. Schistosomiasis in travelers and migrants.Trav Med Infect Dis. 2011; 9: 6-24Crossref PubMed Scopus (92) Google Scholar It is important to have a high index of suspicion in immigrants and travelers for rarely encountered sources of pathology that may have been acquired outside the United States. Although it is unclear the exact duration of our patient's infection, he likely was infected while living in the Sudan.

Acute Schistosomiasis in Travelers: 14 Years' Experience at the Hospital for Tropical Diseases, London

We report 79 cases of acute schistosomiasis. Most of these cases were young, male travelers who acquired their infection in Lake Malawi. Twelve had a normal eosinophil count at presentation and 11 had negative serology, although two had neither eosinophilia nor positive serology when first seen. Acute schistosomiasis should be considered in any febrile traveler with a history of fresh water exposure in an endemic area once malaria has been excluded.

Acute pulmonary schistosomiasis in travelers: Case report and review of the literature

We report the case of an American traveler who developed acute pulmonary schistosomiasis after swimming in a lake in Madagascar, and we review the literature on acute pulmonary schistosomiasis. Schistosomiasis is one of the world's most prevalent parasitic diseases, with three species (Schistosoma mansoni, Schistosoma haematobium and Schistosoma japonicum) causing the greatest burden of disease. Pulmonary manifestations may develop in infected travelers from non-endemic areas after their first exposure. The pathophysiology of acute pulmonary disease is not well-understood, but is related to immune response, particularly via inflammatory cytokines. Diagnosis of schistosomiasis may be either through identification of characteristic ova in urine or stool or through serology. Anti-inflammatory drugs can provide symptomatic relief; praziquantel, the mainstay of chronic schistosomiasis treatment, is likely not effective against acute disease; the only reliable prevention remains avoidance of contaminated freshwater in endemic areas, as there is no vaccine. Travelers who have been exposed to potentially contaminated freshwater in endemic areas should seek testing and, if infected, treatment, in order to avoid severe manifestations of acute schistosomiasis and prevent complications of chronic disease. Clinicians are reminded to elicit a detailed travel and exposure history from their patients.

An outbreak of schistosomiasis in travellers returning from endemic areas: the importance of rigorous tracing in peer groups exposed to risk of infection

Each year, schools across Scotland send their students on exchange programmes to Malawi. Between 2005 and 2009, 22.8% of Scotland's new cases of schistosomiasis were from freshwater exposure in Malawi, with 41.5% diagnosed in 15-24 year olds. In January 2011, a 17-year-old male presented to our urology department with visible haematuria following freshwater exposure during a school trip to Malawi. He was subsequently diagnosed with urinary schistosomiasis. The potential involvement of other individuals from the trip prompted further public health enquiry. The school, public health department and education authorities were notified promptly and all individuals potentially exposed to Schistosoma haematobium were invited for screening. All 21 participants of the exchange programme underwent serological screening. Thirteen tested positive for Schistosoma infection. Only two individuals displayed symptoms of schistosomiasis; the other 11 were asymptomatic. Infection rates, even following a limited exposure to S. haematobium, are high. The majority of seropositive cases may never have symptoms. Therefore, a history of foreign travel to endemic schistosomiasis areas should be sought from any young person presenting with visible heamaturia and appropriate tests instigated. Schools should adopt policies forbidding activities involving freshwater exposure in Malawi. Effective public health measures must be set in place to trace and treat any other possible cases of exposure.

Schistosomiasis in travellers and migrants

Schistosomiasis is a tropical parasitic disease caused by blood-dwelling fluke worms of the genus Schistosoma whose infective stages, the cercariae, are amplified through mollusks acting as intermediate hosts. People are infected when exposed to fresh water containing cercariae that penetrate the skin. There are however considerable differences in intensity of infection and morbidity, depending on the pattern of exposure and the infective species. In travellers, schistosomiasis differs substantially from infection in endemic populations in many aspects: geography, morbidity, treatment and prevention. In migrants, schistosomiasis manifests itself in a way more akin to what is seen in endemic populations. In this paper we will review the specific issues associated with schistosomiasis in travellers and migrants, with emphasis on the acute disease manifestations in non-immune persons, and on neuroschistosomiasis as a potential severe complication. We discuss new trends in diagnosis and treatment with respect to the specific disease stage, and summarize precautionary measures and novel ways to prevent Schistosoma infection in travellers.

Schistosomicidal activity of the antimalarial drug, mefloquine, in Schistosoma mansoni-infected mice

Therapeutic effects of racemic mefloquine were assessed in Schistosoma mansoni-infected mice, and evaluated by recording worm burden, the status of egg maturation and viability, and intestinal mast cell recruitment. Age-matched mice were divided into four groups, of which two were infected. At 8 weeks postinfection, one group of infected and one group of uninfected mice were treated with a single dose of mefloquine (150 mg/kg). Ten days after treatment, all animals were killed. Mefloquine at 150 mg/kg had no effect on worm burden, but significantly reduced the number of eggs in the first three developmental egg stages. Analysis of intestinal mast cell numbers showed that mefloquine induced mastocytosis both in infected and control animals. In conclusion, mefloquine significantly reduces egg production in S. mansoni-infected mice, suggesting a therapeutic potency in schistosomiasis therapy. Mefloquine also exerts a significant proinflammatory effect on the intestine. Through its effect on egg production, mefloquine may be a cause of silent schistosomiasis in travelers using mefloquine for malaria chemoprophylaxis. Further study of the anti-schistosomal activity of mefloquine is warranted, as its activity against other helminths.

Schistosomiasis in travelers and immigrants

Schistosomiasis is caused by trematode parasites of one of five species, Schistosoma mansoni, Schistosoma haematobium, Schistosoma japonicum, Schistosoma intercalatum, or Schistosoma mekongi, acquired via skin contact with fresh water containing infectious larval cercariae. Between 1 and 8 weeks after exposure, acute schistosomiasis presents as dermatitis, fever, fatigue, or eosinophilia. If untreated, long-term infection may cause anemia or undernutrition and may progress to liver fibrosis, portal hypertension, or hydronephrosis. Schistosomiasis represents a threat to residents and visitors in all endemic areas of Africa, Asia, and South America. Travelers should be made aware of infection risk if they become exposed to untreated fresh water. New immigrants and those returning to high-risk areas to visit friends and family should be screened for signs and symptoms of acute and chronic schistosomiasis. Physicians caring for travelers and immigrants must be familiar with the signs and symptoms of schistosomiasis and must be able to diagnose and treat it correctly.

La bilharziose d'importation chez les voyageurs : enquête en France métropolitaine

Objective The clinical presentation of acute schistosomiasis in travellers differs from those observed with chronic schistosomiasis in people from endemic areas. The objective of this study is to describe the main clinical and biological characteristics of the acute schistosomiasis in French travellers. Methods Retrospective study conducted in 42 hospital laboratories of parasitology in France, based on a questionnaire filled out for each case of schistosomiasis diagnosed in subjects non-originating from an endemic country and returning from of a stay in Africa, between 2000 and 2004. Results Seventy-seven cases of acute schistosomiasis diagnosed between 2000 and 2004 were reported by 15 of the 33 laboratories having taken part in the study. The patients were 26 years old on average and 60% were contaminated in West Africa. Seventy patients (91%) presented at least one symptom at the moment of the diagnosis, but only 44 (57%) presented sufficiently intense symptoms to justify a medical consultation spontaneously. The most frequently reported clinical signs were fever (44%), diarrhoea (40%), pruritus (25%), cough (21%) and hematuria (20%). Hypereosinophilia (82%), elevated liver enzymes and positive serology were respectively reported in 82, 23 and 90% of the cases. Ova were found in the urines or the stool in 60% of the cases. Eleven patients were hospitalized. Discussion Acute schistosomiasis must be evoked in patients returning from endemic country and presenting with non-specific symptoms; including patients whose bathes in contaminated water was limited to a short contact of the feet in a river. The high frequency of the asymptomatic or paucisymptomatic forms exposes the infected people to a delayed diagnosis and therefore to an evolution towards the chronic form of schistosomiasis. The increase in tourism towards the endemic areas could be accompanied by an increase in the frequency of the schistosomiasis, and encourages setting-up an active monitoring of acute schistosomiasis.

Schistosome Infection among River Rafters on Omo River, Ethiopia

Adventure trips to Africa have become more frequent, and rafting on some of the great rivers has become almost commonplace. We describe three rafting trips on the Omo River in Ethiopia, after which most of the participants were diagnosed with schistosomiasis. After index cases from the three groups came to medical attention, active surveillance detected outbreaks of illness in a group of American travelers (n = 18 ) in 1993 and in two groups of Israeli travelers in 1997 (n = 26). Of 44 travelers, 37 were screened and 28 (76%) were infected, all with Schistosoma mansoni. Among the infected patients, 16 of 28 (57%) were symptomatic, the most frequent manifestation being fever, which occurred in 14 of 25 (56%); cough occurred in 6 of 18 (33%). Diagnosis was based on FAST-enzyme-linked immunosorbent assay, with confirmation by immunoblot. Other rafting trips on the Omo River sponsored by the same tour companies did not result in symptomatic infection. Investigation of the rafting itineraries suggested the route may have been altered from the usual for these three groups, exposing them to a part of the river that is wider, slower moving, and more densely populated. Schistosomiasis should be considered in febrile patients following rafting trips in schistosome-endemic areas. As asymptomatic schistosomiasis in travelers is also common (43% in this series), all travelers exposed to freshwater in endemic areas should be encouraged to undergo serologic screening.

Schistosomiasis in Travelers and Expatriates.

Background: Several outbreaks of schistosomiasis among travelers, expatriates, and military serviceman have been reported in recent years. Methods: The travel histories and anamnestic and clinical features of 62 patients with schistosomiasis, who presented to a German outpatient clinic specializing in infectious and tropical diseases, were investigated to identify risk factors that could lead to infection in travelers and expatriates. Results: All patients remembered incidents that led to a likely exposure to cercariae of Schistosoma sp. Fifty nine patients (95%) acquired infection in Africa, two (3%) in South America, and one each (2% each) in Iraq and the Mekong River, respectively. The highest proportion of infection (45%) was imported from West Africa. Patients returning from West Africa reported either contact with tributaries of the Niger (including freshwater pools in the Dogon country, Mali) or with waters of the Volta River, notably Lake Volta and/or its delta. Six patients (10%) acquired infection in little-visited areas such as Central Africa and the Congo Basin. East Africa (especially Lake Victoria) and Lake Malawi contributed 14 patients (22%) to our study group; a further nine patients (14%) became infected after contact with waters of the Zambezi River. Conclusions: The most sensitive method for detection of possible infection with schistosomiasis appeared to be a combination of thorough travel history and serologic testing by indirect hemagglutination (IHA), immunofluorescence antibody test (IFAT), and enzyme-linked immunosorbent assay (ELISA). Most infections were acquired by travelers on lengthy and adventurous journeys or by expatriates venturing outside their normal areas of activity. Most patients knew that they had traveled in an area endemic for schistosomiasis, but were uninformed about behavioral risks they had taken in specific settings.

Schistosomiasis in Dogon country, Mali: identification and prevalence of the species responsible for infection in the local community

The prevalence of schistosomiasis amongst the Dogon people in 4 villages and one school of the Bankass district of Mali was determined during 2 surveys in 1992; 1398 urine and 1199 stool samples were examined. The most common schistosome was Schistosoma haematobium, with an overall prevalence of 51.3%; S. mansoni had a prevalence of 12%. No S. intercalatum egg was seen in the stools. Biomphalaria pfeifferi and Bulinus truncatus were found in pools at the base of the Dogon cliffs; Bulinus forskalii was found in smaller numbers in brick pits. Two isolates from urine samples of children were identified as S. haematobium in the laboratory using an α-glycerophosphate marker, restriction enzyme analysis of ribosomal deoxyribonucleic acid (rDNA) and random amplification of polymorphic DNA. The isolates did not develop in Bulinus forskalii or B. crystallinus of the B. forskalii group. Some evidence for past hybridization of S. haematobium and S. intercalatum is provided by the enzyme and rDNA results as well as the positive Ziehl-Neelsen staining of polymorphic eggs in urine samples. The findings are discussed in relation to the published observations concerning schistosomiasis in travellers returning from this region of Mali.

DEVELOPMENT OF CIRCULATING ANTIGEN ASSAY FOR RAPID DETECTION OF ACUTE SCHISTOSOMIASIS

A circulating antigen assay to detect acute schistosomiasis mansoni in experimentally infected mice has been developed. The competitive-inhibition enzyme-linked immunosorbent assay uses rabbit serum prepared against purified cercarial antigen. The assay detects a 100-worm infection as early as 1 week after exposure; circulating antigen levels in mouse serum exceeded 0·1 μg/ml. Preliminary characterisation of the cercarial antigen shows that it is a hydrophobic polypeptide of approximate molecular weight 41 000. A rapid and accurate diagnosis of acute schistosomiasis in travellers would facilitate appropriate chemotherapy before the onset of pathology. A circulating antigen assay would also be valuable for seroepidemiological studies in areas where the disease is endemic.