Health problems and exposure to infectious risks in returning humanitarian aid workers

BACKGROUND

Humanitarian aid workers are exposed to deployment-related health threats. Identifying subgroups at a higher risk of infection in this diverse population could help optimize prevention.

METHODS

We carried out a retrospective study based on anonymized data of humanitarian aid workers that visited our clinic for a post-deployment visit between 1 January 2018 and 31 December 2021. We conducted a descriptive analysis of basic demographic data, self-reported risk exposure and health problems encountered during deployment extracted from a standard questionnaire.

RESULTS

The questionnaire was administered to 1238 aid workers during 1529 post-deployment medical consultations. The median age was 37.2 years (IQR 31.7-44.3), and 718/1529 (47.0%) were female aid workers. The median duration of deployment was 6 months (IQR 3-12 months). Most deployments (1321/1529 (86.4%)) were for a medical organization and in Sub-Saharan Africa (73.2%). The most common risk exposures were contact with freshwater in schistosomiasis endemic regions (187/1308 (14.3%)), unprotected sexual contact with a person other than a regular partner (138/1529 (9.0%)), suspected rabies exposure (56/1529 (3.7%)) and accidental exposure to blood (44/1529 (2.9%)). Gastrointestinal problems (487/1529 (31.9%)), malaria (237/1529 (15.5%)) and respiratory tract infections (94/1529 (6,2%)) were the most encountered health problems. Fifteen volunteers (1%) were hospitalized during deployment and 19 (1.2%) repatriated due to health problems. Adherence to malaria chemoprophylaxis was poor, only taken according to the prescription in 355 out of 1225 (29.0%) of aid workers for whom prophylaxis was indicated.

CONCLUSION

Humanitarian aid workers deployed abroad encounter significant rates of health problems and report a high level of risk exposure during their deployment, with the risks being greatest among younger people, those deployed to rural areas, and those working for non-medical organizations. These findings help guide future pre-deployment consultations, to increase awareness and reduce risk behaviour during deployment, as well as focus on adherence to medical advice such as malaria chemoprophylaxis.

Cutaneous schistosomiasis: epidemiological and clinical characteristics in returning travelers

The clinical manifestations of parasitic diseases are well-covered in the infectious disease literature; however, cutaneous manifestations often receive limited attention. There is a need to update existing knowledge and improve reporting of disease characteristics. Given continued increases in travel and transportation, more individuals are acquiring cutaneous infections while traveling abroad. Schistosomiasis is the second most important tropical disease among returning travelers and affects more than 200 million individuals worldwide. The literature classically describes three forms of skin disease in those infected with Schistosoma: the immediate pruritic eruption of cercarial dermatitis, the urticarial response of Katayama syndrome, and the granulomatous lesions of late cutaneous schistosomiasis. Over the last two decades, more atypical presentations have been described. Travelers returning from Africa, South America, and Asia are at highest risk given these are the continents in which the parasite is endemic. This review highlights the cutaneous manifestations of schistosomiasis, with a focus on international travelers with atypical presentations. Additionally, genital schistosomiasis will be reviewed given its significant morbidity. The aim of this review is to update the current body of literature. Dermatologists and other physicians evaluating the skin should be aware of the following principles regarding schistosomal infections: (i) the importance of an early skin biopsy in making the diagnosis; (ii) the necessity of adding schistosomiasis to the differential diagnosis for zosteriform lesions; (iii) the resemblance of chronic cutaneous schistosomiasis of the genitals to sexually transmitted infections; and (iv) the need to revise definitions for early and late infection, specifically for cutaneous disease.

One Health Concept against Schistosomiasis: An Overview

Schistosomiasis (bilharziasis) is a parasitic disease caused by Schistosoma spp. that belongs to trematode worms. These worms are known as “blood parasites”. This disease is included in “neglected tropical diseases” and “water-borne diseases”. The main species are Schistosoma (S.) haematobium, S. japonicum, S. mansoni, S. intercalatum, S. mekongi, S. guineensis and S. intercalatum, though there are more than 20 different species. The parasite in the definitive host may affect many organs and systems. The disease may become chronic and lasts 3–8 years and even up to 20–30 years. The definitive host is primarily human; however, in endemic areas animals such as monkeys, cattle, horses, rodents, cats, dogs are reservoirs. According to World Health Organization (WHO), schistosomiasis affects 250 million people, and causes 1.9 million deaths yearly in endemic areas. Moreover, due to global warming, the spread of the disease may increase. The effective way to fight against schistosomiasis is following the “one-health system”. Indeed, to overcome or “eradicate” this disease, we have to strive against different forms at different evolutionary stages of the worm such as, forms in humans, domestic or wild animals, and freshwater snails. If we combine the knowledge of professionals, we may achieve this goal.

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.

Clinical Spectrum of Schistosomiasis: An Update

Schistosomiasis is a helminthic infection and one of the neglected tropical diseases (NTDs). It is caused by blood flukes of the genus Schistosoma. It is an important public health problem, particularly in poverty-stricken areas, especially those within the tropics and subtropics. It is estimated that at least 236 million people worldwide are infected, 90% of them in sub-Saharan Africa, and that this disease causes approximately 300,000 deaths annually. The clinical manifestations are varied and affect practically all organs. There are substantial differences in the clinical presentation, depending on the phase and clinical form of schistosomiasis in which it occurs. Schistosomiasis can remain undiagnosed for a long period of time, with secondary clinical lesion. Here, we review the clinical profile of schistosomiasis. This information may aid in the development of more efficacious treatments and improved disease prognosis.

Schistosoma haematobium infection with pulmonary involvement in a traveller returning from Congo: A case report and systematic review of literature on nodular pulmonary schistosomiasis

BACKGROUND

Schistosomiasis is highly prevalent in sub-Saharan Africa and diagnosis is difficult for travel medicine practitioners, because it can affect different organs with atypical manifestations. S. haematobium is mostly associated with urinary involvement and rarely with pulmonary lesions. This review aims to summarise the pulmonary forms associated with schistosomiasis, especially with S. haematobium.

METHOD

Based on a case report of both pulmonary and urogenital schistosomiasis, we performed a systematic literature review of schistosomiasis occurring in migrants and travellers, with a specific focus on pulmonary schistosomiasis.

RESULTS

Pulmonary schistosomiasis can present two different clinical patterns. On the one hand, there is an acute pattern, which more frequently affects non-immune young travellers within three to eight weeks of their return and, on the other hand, there is a chronic pattern, which has been evolving in recent years and which mostly affects people living in endemic areas or migrating from these countries. Nodular pulmonary lesions are described in both patterns. Genus identification should not focus only on known patterns, and identification of S. haematobium should not be associated exclusively with urinary schistosomiasis.

CONCLUSIONS

Pulmonary schistosomiasis, even when resulting from S. haematobium, is a rare but existing infection that appears to be spreading with increasing travel and global migration. Physicians need to be more aware of non-specific symptoms that may reveal an atypical presentation of a tropical disease, in order to avoid the chronic complications which can result from parasitic diseases.

Acute schistosomiasis in paediatric travellers and comparison with their companion adults

BACKGROUND

Schistosomiasis in non-immune travellers can cause acute schistosomiasis, a multi-systemic hypersensitivity reaction. Little is known regarding acute schistosomiasis in children. We describe acute schistosomiasis in paediatric travellers and compare them with adult travellers.

METHODS

A retrospective study of paediatric travellers (0-18 years old) diagnosed with schistosomiasis at Sheba Medical Center. Patients' findings are compared with those of adult travellers from the same travel groups.

RESULTS

in total, 18 children and 24 adults from five different trips to Tanzania, Uganda, Nigeria and Laos were infected (90% of the exposed travellers). The median bathing time of the infected children was 30 min (interquartile range (IQR) 15-30 min). The most common presentations were respiratory symptoms in 13 (72%), eosinophilia in 13 (72%) and fever in 11 (61%). Acute illness included a median of 2.5 symptoms. Three children required hospitalization and three were asymptomatic. Fatigue was significantly less common in children compared with similarly exposed adults (33% vs 71%, P = 0.03). Rates of hospitalization and steroid treatment were similar. The median eosinophil count in children was 1045 cells/μl (IQR 625-2575), lower than adults [2900 cells/μl (IQR 1170-4584)], P = 0.02.

CONCLUSIONS

Children may develop acute schistosomiasis following short exposure to contaminated freshwater, demonstrating a high infection rate. Severity seems to be similar to adults, although children report fatigue less commonly and show lower eosinophil counts. The disease should be suspected in children with multi-systemic illness and in asymptomatic children with relevant travel history.

Molecular approach to the epidemiology of urinary schistosomiasis in France

BACKGROUND

The diagnosis of urogenital schistosomiasis is based on the complementarity of serological technique and microscopic examination (ME). Between 2015 and 2019, the number of urinary schistosomiasis tests received in our laboratory increased sharply from 300 to 900 per year. Therefore, we wanted to evaluate the reliability of urine microscopic examination (ME, reference and routine technique) from urine sample by comparing it to other techniques (antigenic technique and PCR). To this end, we optimized two real-time PCRs targeting respectively Schistosoma haematobium (Sh) and Schistosoma mansoni (Sm).

METHODOLOGY/PRINCIPAL FINDINGS

914 urine samples from 846 patients suspected of urogenital schistosomiasis were prescribed and analyzed by PCR and also by antigenic technique for the first 143 samples. The antigenic technique evaluated was Schisto POC-CCA, Rapid Medical Diagnostics. These results (antigenic technique and PCR) were compared to ME which was performed from all urines. The percentage of 14% (128/914) positive cases with the PCR technique and the percentage of 6.0% (54/914) positive cases with ME is significantly different (Chi 2 test, p<0.001). These 128 positive PCRs correspond to 120 different patients, 88.3% (106/120) of them were young migrants and 11.7% (14/120) were French patients returning from travel. Among these migrants, more than 75% (80/106) came from French-speaking West Africa. In addition, the Schisto POC-CCA showed a specificity of 39% (46/117), too poor to be used as a screening tool in low or non-endemic areas.

CONCLUSION/SIGNIFICANCE

Targeted Sh and Sm PCRs in urine are reliable techniques compared to ME (reference technique). In view of our results, we decided to screen urinary schistosomiasis by direct ME always coupled by the PCR technique, which has shown better reliability criteria.

Population genetics of African Schistosoma species

Blood flukes within the genus Schistosoma (schistosomes) are responsible for the major disease, schistosomiasis, in tropical and sub-tropical areas. This disease is predominantly present on the African continent with more than 85% of the human cases. Schistosomes are also parasites of veterinary importance infecting livestock and wildlife. Schistosoma population genetic structure and diversity are important characteristics that may reflect variations in selection pressures such as those induced by host (mammalian and snail) environments, habitat change, migration and also treatment/control interventions, all of which also shape speciation and evolution of the whole Schistosoma genus. Investigations into schistosome population genetic structure, diversity and evolution has been an area of important debate and research. Supported by advances in molecular techniques with capabilities for multi-locus genetic analyses for single larvae schistosome genetic investigations have greatly progressed in the last decade. This paper aims to review the genetic studies of both animal and human infecting schistosome. Population genetic structures are reviewed at different spatial scales: local, regional or continental (i.e. phylogeography). Within species genetic diversities are discussed compared and the compounding factors discussed, including the effect of mass drug administration. Finally, the ability for intra-species hybridisation questions species integrities and poses many questions in relation to the natural epidemiology of co-endemic species. Here we review molecularly confirmed hybridisation events (in relation to human disease) and discuss the possible impact for ongoing and future control and elimination.

Tropical Infections in Returning Travelers

In the modern era, the relative ease and faster speed of travel have made the world a global village. An increasing number of people are traveling to distant and sometimes exotic locations for vacation/leisure or at times for business purposes. Along with the experiences of far-fetched lands, sometimes they bring bugs/organisms that are not native to their motherland. This makes the diagnosis and management of illnesses in a traveler challenging. In this review, we have tried to outline a management protocol for travelers returning with fever, with specific emphasis on trypanosomiasis and schistosomiasis.

How to cite this article: Suri V, Bhalla A. Tropical Infections in Returning Travelers. Indian J Crit Care Med 2021;25(Suppl 2):S175–S183.

Antigen-based diagnosis of Schistosoma infection in travellers: a prospective study

BACKGROUND

Travellers infected with Schistosoma spp. might be pauci- or even asymptomatic on first presentation. Therefore, schistosomiasis may remain undiagnosed in this population. Active infection, as evidenced by the presence of the tissue-dwelling worm, can be demonstrated via the detection of adult worm-derived circulating anodic antigen (CAA) utilising a robust well-described lateral flow-(LF) based test applying background-free up-converting reporter particles (UCP). In this prospective study, we assessed the diagnostic value of serum and urine UCP-LF CAA test in comparison with two Schistosoma-specific serological assays detecting antibodies against adult worm antigen-immuno fluorescence assay (AWA-IFA) and against soluble egg antigen-enzyme-linked immunosorbent assay (SEA-ELISA) antigens in travellers.

METHODS

Samples were collected from 106 Dutch travellers who reported freshwater contact in sub-Saharan Africa and who were recruited up to 2 years after return. Subjects were asked to complete a detailed questionnaire on travel history, water contact, signs and symptoms compatible with schistosomiasis.

RESULTS

Two travellers were positive by serum CAA and an additional one by urine CAA. A total of 22/106 (21%) samples were antibody positive by AWA-IFA and 9/106 (9%) by SEA-ELISA. At follow-up 6 weeks and 6 months after praziquantel treatment, all seropositives remained antibody positive whereas CAA was cleared. Seropositivity could not be predicted by the type of fresh water-related activity, country visited or symptoms reported.

CONCLUSION

The low number of UCP-LF CAA positives suggests that in travellers, active infections often do not establish or have very low worm burden. Based on our high seroconversion rates, we conclude that the AWA-IFA assay is the most sensitive test to detect schistosome exposure. Given the lack of predictive symptoms or risk factors, we recommend schistosomiasis screening at least by serology in all travellers with reported freshwater contact in high-endemic areas.

Retrospective study on imported schistosomiasis in Morocco between 2005 and 2017

Since 2004, no indigenous cases of schistosomiasis have been found in Morocco; only imported cases have been detected. The aim of the present study was to describe and analyse the epidemiological profile of imported schistosomiasis between 2005 and 2017, and, by this, attract attention to the probability of a reintroduction of this disease. During this period, 27 cases were recorded in Morocco, with a male predominance (13:1). All cases reported were found among African immigrants from Mauritania (37%), Mali (18%) and Senegal (15%). Schistosoma heamatobium was the most dominant specie. Most cases were reported in Rabat and Agadir, where there are many snail habitats. To prevent a re-emergence of the disease, the main challenge would be to consolidate and maintain a sustainable surveillance and control system of the importation of bilharzia. The frequency of asymptomatic schistosomiasis justifies a systematic health check-up for all travellers, migrants and immigrants.

Delay in schistosomiasis diagnosis and treatment: a multicenter cohort study in Italy

BACKGROUND

Barriers to access to care, different diagnostic strategies and low awareness remain challenging issues in the fight against schistosomiasis.Our study aims to examine management of schistosomiasis in migrants attending large tertiary hospitals in Italy, in order to call for a comprehensive approach.

METHODS

A retrospective review of schistosomiasis cases was carried out between January 1, 2016, and December 31, 2017, in five large Infectious Disease Centers in Italy. We included all patients diagnosed with schistosomiasis. We differentiated among (i) asymptomatic patients diagnosed by serology either as healthy 'migrant evaluation' or as 'late evaluation' in patients followed because of a different infection and (ii) patients tested because of a suggestive clinical presentation. Patients characteristics and clinical data were recorded.

RESULTS

One hundred forty-nine patients were included, 137 (91.9%) were male, the median age was 26 years and 70% of them came from Sub-Saharan Africa.Thirty-eight asymptomatic patients (25.5%) were diagnosed by serology [15, (10.1%) among 'migrant evaluation' and 23 (15.4%) among 'late evaluation' group], and 111 (74.5%) presented with signs/symptoms.The median diagnostic delay from arrival in Italy was 31 months: 110 for asymptomatic group and 16 months for symptomatic patients. Among the 111 symptomatic patients, 41 individuals were already followed in our clinics, and they never underwent screening before appearance of evident disease. Among patients with positive serology who were tested by microscopy, 32/86 (37.2%) had confirmed diagnosis. Forty-five (37.8%) patients presented radiologic abnormalities. Praziquantel was the treatment of choice (70.1% for 3 days and 29.9% in a single-day dose), and 77 (51.7%) were lost to follow-up.

CONCLUSIONS

In our centers, a high proportion of patients were tested late after arrival, and most of them presented with clinical apparent disease. Well-defined strategies and implementation of recent guidelines are needed to improve early diagnosis and to overcome heterogeneity of practice.

Currently Available Monitoring and Surveillance Systems for Taenia spp., Echinococcus spp., Schistosoma spp., and Soil-Transmitted Helminths at the Control/Elimination Stage: A Systematic Review

An increasing global focus on neglected tropical diseases (NTDs) has resulted in the set up of numerous control and elimination activities worldwide. This is partly true for Taenia solium taeniasis/cysticercosis, the most important foodborne parasitic infection. Despite substantial progress, adequate monitoring and surveillance (M&S) are required to sustain a status of control/elimination. This is often lacking, especially for T. solium. Therefore, the objective was to conduct a systematic literature review of the currently available M&S systems at the control/elimination stage of the four top-ranked helminth NTDs. Specifically, Taenia spp., Echinococcus spp., Schistosoma spp., and soil-transmitted helminths (STHs) were considered to determine if there are any similarities between their M&S systems and whether certain approaches can be adopted from each other. The systematic review demonstrated that rigorous M&S systems have been designed for the control/elimination stage of both STHs and schistosomiasis, particularly in China. On the other hand, a concept of M&S for Taenia spp. and Echinococcus spp. has not been fully developed yet, due to a lack of epidemiological data and the fact that many endemic countries are far away from reaching control/elimination. Moreover, accurate diagnostic tools for all four diseases are still imperfect, which complicates proper M&S. Finally, there is an urgent need to develop and harmonize/standardize M&S activities in order to reliably determine and compare the epidemiological situation worldwide.

Schistosomiasis in immigrants, refugees and travellers in an Italian referral centre for tropical diseases

BACKGROUND

Schistosomiasis is one of the most important neglected tropical diseases. If unrecognised and untreated, the chronic infection can lead to irreversible complications.

METHODS

Retrospective observational study aimed at describing clinical history, laboratory findings and imaging presentation of imported schistosomiasis diagnosed at the Centre for Tropical Diseases, Sacro Cuore Don Calabria Hospital of Negrar, Verona, Italy from 2010 to 2014. The aim of our study was to assess differences in demographic characteristics, clinical presentation, laboratory data and ultrasound findings between immigrants/visiting friends and relatives (VFR) from endemic countries (endemic group) and expatriates/travellers (non-endemic group).

RESULTS

A total of 272 patients were retrieved: 234 in the endemic and 38 in the non-endemic group. Most of the patients acquired schistosomiasis in Africa (97.4%). Symptoms were reported by 52.9% of the patients; abdominal pain (36%), macroscopic hematuria (11.3%), and genito-urinary symptoms (7.4%) being the most frequently reported. Increased IgE and blood eosinophilia were observed in 169 (63.8%) and 130 (47.8%) patients, respectively. The proportion of positive serology was 250/272 (91.9%).The Circulating Cathodic Antigen CCA for Schistosoma mansoni was positive in 14/61 individuals (23%). At microscopy, infected subjects were 103/272 (37.9%). The species of Schistosoma found were S. haematobium (47.6%), S. mansoni (46.6%) or both (5.8%). Schistosomiasis was classified as confirmed in 103 (37.9%), probable in 165 (60.6%) and suspected in 4 (1.5%) cases using clinical presentation, laboratory data and ultrasound findings. The infection was further classified based on organ involvement: intestinal (17.9%), hepatosplenic (5.1%), urogenital (48.9%), and indeterminate (43.8%). The comparative analysis of endemic and non-endemic patients highlighted differences in sex and age. Endemic patients had more frequent ova identification (41.9% vs. 13.2%, P < 0.001) and increased IgE (70% vs. 26.3%, P < 0.001) when compared with non-endemic. Multivariate analyses showed that younger age, abnormal ultrasound findings and blood eosinophilia were significantly associated with positive microscopy (OR = 0.94, OR = 2.12, OR = 1.98, respectively).

CONCLUSIONS

Symptoms, eosinophilia and abnormal ultrasound findings were present in about half of patients, without differences between groups. Many patients had positive serology but negative microscopy, indicating that schistosomiasis might be misdiagnosed. A combination of diagnostic tools may facilitate the diagnosis.

Preventing diseases in round-the-world travelers: a contemporary challenge for travel medicine advice

Providing advice for travelers embarking on long-term trips poses a challenge in travel medicine. A long duration of risk exposure is associated with underuse of protective measures and poor adherence to chemoprophylaxis, increasing the chances of acquiring infections. Recently, in our clinic, we observed an increase in the number of travelers undertaking round-the-world trips. These individuals are typically aged around 32 years and quit their jobs to embark on one-to-two-year journeys. Their destinations include countries in two or more continents, invariably Southeast Asia and Indonesia, and mostly involve land travel and visiting rural areas. Such trips involve flexible plans, increasing the challenge, especially with regard to malaria prophylaxis. Advising round-the-world travelers is time-consuming because of the amount of information that must be provided to the traveler. Advisors must develop strategies to commit the traveler to his/her own health, and verify their learnings on disease-prevention measures. Contacting the advisor after the appointment or during the trip can be helpful to clarify unclear instructions or diagnosis made and prescriptions given abroad. Infectious diseases are among the most frequent problems affecting travelers, many of which are preventable by vaccines, medicines, and precautionary measures. The dissemination of counterfeit medicines, particularly antibiotics and antimalarial medicines, emphasizes the need for travelers to carry medicines that they may possibly need on their trip. Additional advice on altitude, scuba diving, and other possible risks may also be given. Considering the difficulties in advising this group, we present a review of the main recommendations on advising these travelers.

Positive fecal occult blood test as a diagnostic cue for Schistosoma mansoni infection in a developed country

The rise in eco-tourism and travel off the beaten track have increased numbers of tourists with schistosomiasis which is seldom seen in developed countries, although this disease is considered a neglected tropical disease especially in poor communities. A Guinean male living in Japan was seen complaining of severe constipation. He was positive for fecal occult blood (FOB) and underwent colonoscopy. Colonoscopy showed petechiae of the rectal mucosa, with pathologic examination of biopsy tissue showing calcified eggs of the genus Schistosoma. Direct examination of eggs in feces and antibody tests of serum confirmed the diagnosis of schistosomiasis. The patient was administered Praziquantel (400 mg/day for 2 days) and FOB and fecal ova tests were negative after treatment. FOB tests have been reported as a useful assessment of morbidities associated with intestinal schistosomiasis. In developed countries, positive FOB result, which is used as a main examination for bowel malignant disease, are not recognized as being due to schistosomiasis. As this tropical disease is rarely present in developed countries, it may be under-diagnosed. Schistosomiasis should be included in the differential diagnosis of patients with positive FOB tests.

Schistosomiasis in European Travelers and Migrants: Analysis of 14 Years TropNet Surveillance Data

Schistosomiasis remains one of the most prevalent parasitic diseases worldwide and the infection is frequently found in travelers and migrants. The European Network for Tropical Medicine and Travel Health conducted a sentinel surveillance study on imported schistosomiasis between 1997 and 2010. This report summarizes epidemiological and clinical data from 1,465 cases of imported schistosomiasis. Direct pathogen detection and serology were the main diagnostic tools applied. Of these, 486 (33%) cases were identified among European travelers, 231 (16%) among long-term expatriates, and 748 (51%) among non-European immigrants. Overall, only 18.6% of travelers had received pretravel advice; 95% of infections were acquired in the African region. On species level, Schistosoma mansoni was identified in 570 (39%) and Schistosoma haematobium in 318 (22%) cases; 57.5% of patients were symptomatic. Acute symptoms were reported in 27% of patients leading to earlier presentation within 3 months. Praziquantel was used in all patients to treat schistosomiasis. Many infections were detected in asymptomatic patients. In 47.4% of asymptomatic patients infection was detected by microscopy and in 39% by serology or antigen testing. Schistosomiasis remains a frequent infection in travelers and migrants to Europe. Travelers should be made aware of the risk of schistosomiasis infection when traveling to sub-Saharan Africa. Posttravel consultations particularly for returning expatriates are useful given the high potential for detecting asymptomatic infections.

Diagnosing Urogenital Schistosomiasis: Dealing with Diminishing Returns

Urogenital schistosomiasis, caused by Schistosoma haematobium, is the most prevalent form of schistosomiasis affecting humans, and can result in severe bladder, kidney, ureteral, and genital pathologies. Chronic infection with S. haematobium has been linked with bladder cancer and increased risk for HIV infection. As mass drug administration with praziquantel increases in an attempt to transition from control to elimination of schistosomiasis, the need for updated, more sensitive diagnostic tools becomes more apparent, especially for use in areas of low infection intensity and for individuals with light infections. Here, we review established and investigational diagnostic tests utilized for urogenital schistosomiasis, highlighting new insights and recent advances.

Therapeutic effect of mefloquine on Schistosoma mansoni in experimental infection in mice

Schistosomiasis is one of the most prevalent parasitic infections worldwide. Praziquantel is the drug of choice for treatment of schistosomiasis for its high efficacy. The present work was carried out on 160 mice to evaluate the therapeutic effect of mefloquine on experimental schistosomiasis mansoni. Mice were classified into 3 groups; group I (20 infected non-treated mice), group II included 60 infected mice which were further divided into group IIm (20 mice treated with 400 mg/kg mefloquine), group IIp (20 mice treated with 1,000 mg/kg/2 days praziquantel) and group IIpm (20 mice treated with 200 mg/kg mefloquine and 500 mg/kg praziquantel), group III included 80 non-infected mice subdivided into group IIIn (20 non-treated mice), group IIIm (20 mice treated with 400 mg/kg mefloquine), group IIIp (20 mice treated with 1,000 mg/kg/2 days praziquantel), group IIIpm (20 mice treated with 200 mg mefloquine and 500 mg praziquantel). Mefloquine significantly reduced worm burden, tissue egg load, number of liver granulomas and increased the percent of dead ova within granulomas. Combination of mefloquine and praziquantel gave better curative effects than praziquantel or mefloquine given alone.

Mucocutaneous manifestations of helminth infections: Trematodes and cestodes

In the 21st century, despite increased international travel for vacation, work, and medical missions and immigration into the United States, there is little published in the dermatology literature regarding the cutaneous manifestations of helminth infections. It has been estimated that 20% to 70% of international travelers suffer from some travel-related health problem. Approximately 17% of travelers seek medical care because of cutaneous disorders, many related to infectious etiologies. This review will focus on cutaneous diseases caused by helminth infections. Part I of the review focused on nematode infections; part II will focus on trematode and cestode infections. Nematodes are roundworms that cause diseases with cutaneous manifestations, such as cutaneous larval migrans, onchocerciasis, filariasis, gnathostomiasis, loiasis, dracunculiasis, strongyloidiasis, ascariasis, streptocerciasis, dirofilariasis, and trichinosis. Tremadotes, also known as flukes, cause schistosomiasis, paragonimiasis, and fascioliasis. Cestodes (tapeworms) are flat, hermaphroditic parasites that cause diseases such as sparganosis, cysticercosis, and echinococcus.

Early Detection of Schistosoma Egg-Induced Pulmonary Granulomas in a Returning Traveler

We report the case of a French traveler who developed acute pulmonary schistosomiasis 2 months after visiting Benin. He presented with a 1-month history of fever, cough, and thoracic pain. Initial investigations revealed hypereosinophilia and multiple nodular lesions on chest computed tomography scan. Lung biopsies were performed 2 months later because of migrating chest infiltrates and increasing eosinophilia. Histological examination showed schistosomal egg-induced pulmonary granulomas with ova exhibiting a prominent terminal spine, resembling Schistosoma haematobium. However, egg shells were Ziehl-Neelsen positive, raising the possibility of a Schistosoma intercalatum or a Schistosoma guineensis infection. Moreover, involvement of highly infectious hybrid species cannot be excluded considering the atypical early pulmonary oviposition. This case is remarkable because of the rarity of pulmonary schistosomiasis, its peculiar clinical presentation and difficulties in making species identification. It also emphasizes the need to consider schistosomiasis diagnosis in all potentially exposed travelers with compatible symptoms.

Acute schistosomiasis: a risk underestimated by travelers and a diagnosis frequently missed by general practitioners-a cluster analysis of 42 travelers

BACKGROUND

In 2011, a patient was admitted to our hospital with acute schistosomiasis after having returned from Madagascar and having bathed at the Lily waterfalls. On the basis of this patient's indication, infection was suspected in 41 other subjects. This study investigated (1) the knowledge of the travelers about the risks of schistosomiasis and their related behavior to evaluate the appropriateness of prevention messages and (2) the diagnostic workup of symptomatic travelers by general practitioners to evaluate medical care of travelers with a history of freshwater exposure in tropical areas.

METHODS

A questionnaire was sent to the 42 travelers with potential exposure to schistosomiasis. It focused on pre-travel knowledge of the disease, bathing conditions, clinical presentation, first suspected diagnosis, and treatment.

RESULTS

Of the 42 questionnaires, 40 (95%) were returned, among which 37 travelers (92%) reported an exposure to freshwater, and 18 (45%) were aware of the risk of schistosomiasis. Among these latter subjects, 16 (89%) still reported an exposure to freshwater. Serology was positive in 28 (78%) of 36 exposed subjects at least 3 months after exposure. Of the 28 infected travelers, 23 (82%) exhibited symptoms and 16 (70%) consulted their general practitioner before the information about the outbreak had spread, but none of these patients had a serology for schistosomiasis done during the first consultation.

CONCLUSIONS

The usual prevention message of avoiding freshwater contact when traveling in tropical regions had no impact on the behavior of these travelers, who still went swimming at the Lily waterfalls. This prevention message should, therefore, be either modified or abandoned. The clinical presentation of acute schistosomiasis is often misleading. General practitioners should at least request an eosinophil count, when confronted with a returning traveler with fever. If eosinophilia is detected, it should prompt the search for a parasitic disease.

Approach to the international traveler with neurological symptoms

ABSTRACT 

International travelers commonly contract illnesses while abroad, with the highest risk in those who spend extended time in developing countries. As travel to worldwide destinations becomes more accessible, neurologists should be aware of travel-related infections and noninfectious conditions presenting with neurological manifestations. Travelers may present with a myriad of neurologic symptoms, including confusion, headache, weakness and sensory symptoms. In this review, we discuss the general approach to the returning traveler with neurological symptoms and discuss the differential diagnosis of symptoms commonly encountered in practice.

Regional variation in travel-related illness acquired in Africa, March 1997-May 2011

To understand geographic variation in travel-related illness acquired in distinct African regions, we used the GeoSentinel Surveillance Network database to analyze records for 16,893 ill travelers returning from Africa over a 14-year period. Travelers to northern Africa most commonly reported gastrointestinal illnesses and dog bites. Febrile illnesses were more common in travelers returning from sub-Saharan countries. Eleven travelers died, 9 of malaria; these deaths occurred mainly among male business travelers to sub-Saharan Africa. The profile of illness varied substantially by region: malaria predominated in travelers returning from Central and Western Africa; schistosomiasis, strongyloidiasis, and dengue from Eastern and Western Africa; and loaisis from Central Africa. There were few reports of vaccine-preventable infections, HIV infection, and tuberculosis. Geographic profiling of illness acquired during travel to Africa guides targeted pretravel advice, expedites diagnosis in ill returning travelers, and may influence destination choices in tourism.

Travel-associated disease among US residents visiting US GeoSentinel clinics after return from international travel

BACKGROUND

US residents make 60 million international trips annually. Family practice providers need to be aware of travel-associated diseases affecting this growing mobile population.

OBJECTIVE

To describe demographics, travel characteristics and clinical diagnoses of US residents who present ill after international travel.

METHODS

Descriptive analysis of travel-associated morbidity and mortality among US travellers seeking care at 1 of the 22 US practices and clinics participating in the GeoSentinel Global Surveillance Network from January 2000 to December 2012.

RESULTS

Of the 9624 ill US travellers included in the analysis, 3656 (38%) were tourist travellers, 2379 (25%) missionary/volunteer/research/aid workers (MVRA), 1580 (16%) travellers visiting friends and relatives (VFRs), 1394 (15%) business travellers and 593 (6%) student travellers. Median (interquartile range) travel duration was 20 days (10-60 days). Pre-travel advice was sought by 45%. Hospitalization was required by 7%. Compared with other groups of travellers, ill MVRA travellers returned from longer trips (median duration 61 days), while VFR travellers disproportionately required higher rates of inpatient care (24%) and less frequently had received pre-travel medical advice (20%). Illnesses of the gastrointestinal tract were the most common (58%), followed by systemic febrile illnesses (18%) and dermatologic disorders (17%). Three deaths were reported. Diagnoses varied according to the purpose of travel and region of exposure.

CONCLUSIONS

Returning ill US international travellers present with a broad spectrum of travel-associated diseases. Destination and reason for travel may help primary health care providers to generate an accurate differential diagnosis for the most common disorders and for those that may be life-threatening.

Urinary schistosomiasis

Schistosomiasis is the second most common socio-economically devastating parasitic disease after malaria, affecting about 240 million residents of developing countries. In Africa, it predominantly manifests as urogenital disease, and the main infective agent is Schistosoma hematobium. Endemicity is propagated by poor socio-economic status and environmental degradation due to rapid urbanization. Recreational swimming is a potent medium for the spread of disease in children and adolescents. Most affected individuals are asymptomatic. The male and female worms are equipped with an extraordinary capacity for immune evasion and are able to co-habit for several decades within the pelvic venous plexus. Eggs deposited in the bladder wall resist elimination by type 1 T lymphocytes. Instead, they are sustained by pro-fibrogenic encapsulation (as modulated by type 2 helper cells). Progressive bladder disease results in obstructive uropathy and predisposes to (mostly) squamous cell carcinoma. Schistosomal glomerulopathy manifests as a clinical spectrum of asymptomatic proteinuria, nephrosis and/or nephritic syndrome. Findings on renal biopsy may be influenced by co-morbidity with Salmonella bacteria, amyloidosis and hepatitis C infection. Potentially fatal Katayama fever and spinal radiculopathy may ensue in tourists visiting an endemic zone. Early detection by urine microscopy is hampered by low urinary excretion rates of the parasite eggs. Although useful in travelers with newly acquired disease, the results of the serological antibody assay may be false positive in residents of an endemic zone. Cystoscopy, however, may be invaluable. Due to its safety, effectiveness and once-daily dosing, praziquantel is the drug of choice. An integrated approach that includes mass chemotherapy, environmental health programs and public health education is the most cost-effective preventive strategy.

Sex bias in the outcome of human tropical infectious diseases: influence of steroid hormones

Numerous investigations have revealed a bias toward males in the susceptibility to and severity of a variety of infectious diseases, especially parasitic diseases. Although different external factors may influence the exposure to infection sources among males and females, one recurrent phenomenon indicative of a hormonal influence is the simultaneous increase in disease occurrence and hormonal activity during the aging process. Substantial evidence to support the influence of hormones on disease requires rigorously controlled human population studies, as well as the same sex dimorphism being observed under controlled laboratory conditions. To date, only very few studies conducted have fulfilled these criteria. Herein, we introduce tropical infectious diseases, including amebiasis, malaria, leishmaniasis, toxoplasmosis, schistosomiasis, and paracoccidioidomycosis, in which hormones are suspected to play a role in disease processes. We summarize the most recent findings from epidemiologic studies in humans and from hormone replacement studies in animal models, as well as data regarding the influence of hormones on immune responses underlying the pathology of the diseases.

A Schistosoma haematobium-specific real-time PCR for diagnosis of urogenital schistosomiasis in serum samples of international travelers and migrants

BACKGROUND

Diagnosis of urogenital schistosomiasis by microscopy and serological tests may be elusive in travelers due to low egg load and the absence of seroconversion upon arrival. There is need for a more sensitive diagnostic test. Therefore, we developed a real-time PCR targeting the Schistosoma haematobium-specific Dra1 sequence.

METHODOLOGY/PRINCIPAL FINDINGS

The PCR was evaluated on urine (n = 111), stool (n = 84) and serum samples (n = 135), and one biopsy from travelers and migrants with confirmed or suspected schistosomiasis. PCR revealed a positive result in 7/7 urine samples, 11/11 stool samples and 1/1 biopsy containing S. haematobium eggs as demonstrated by microscopy and in 22/23 serum samples from patients with a parasitological confirmed S. haematobium infection. S. haematobium DNA was additionally detected by PCR in 7 urine, 3 stool and 5 serum samples of patients suspected of having schistosomiasis without egg excretion in urine and feces. None of these suspected patients demonstrated other parasitic infections except one with Blastocystis hominis and Entamoeba cyst in a fecal sample. The PCR was negative in all stool samples containing S. mansoni eggs (n = 21) and in all serum samples of patients with a microscopically confirmed S. mansoni (n = 22), Ascaris lumbricoides (n = 1), Ancylostomidae (n = 1), Strongyloides stercoralis (n = 1) or Trichuris trichuria infection (n = 1). The PCR demonstrated a high specificity, reproducibility and analytical sensitivity (0.5 eggs per gram of feces).

CONCLUSION/SIGNIFICANCE

The real-time PCR targeting the Dra1 sequence for S. haematobium-specific detection in urine, feces, and particularly serum, is a promising tool to confirm the diagnosis, also during the acute phase of urogenital schistosomiasis.

Schistosomiasis: current epidemiology and management in travelers

Schistosomiasis is increasingly encountered among travelers returning from the tropics, mainly from Africa. Schistosoma-infected travelers have served as sentinels for the existence of unknown foci of transmission even outside Africa. Acute schistosomiasis (also termed Katayama syndrome) is the common manifestation among travelers and may follow exposure to any of the Schistosoma species. Neuroschistosomiasis is a rare complication but may result in severe disability. Diagnosis in travelers is hampered by the poor sensitivity of microscopy in urine and stool, especially during acute infections, while seroconversion may be delayed for a period of weeks. During acute schistosomiasis, symptomatic treatment is the only available therapy, while for chronic schistosomiasis, praziquantel is the only drug available, despite reports of emerging resistance to it. Since the potential for exposure to Schistosoma through travel will probably continue to increase, it is clear that new, sensitive diagnostic methods and drugs affecting the parasite in all its stages are needed.

Neuroschistosomiasis mansoni: literature review and guidelines

BACKGROUND

Schistosomiasis is a tropical disease caused by worms of the genus Schistosoma. It is endemic in the Caribbean Islands, the middle east, eastern Asia, South America, and Africa. In nonendemic areas, physicians should be aware of this condition in travelers returning from endemic areas and in immigrants. The main disease-causing species are Schistosoma haematobium, Schistosoma mansoni, and Schistosoma japonicum. Neuroschistosomiasis is an ectopic form of the disease that is mainly associated with S. japonicum infection. Involvement of the central nervous system (CNS) in S. mansoni infection is neglected and underestimated. Neuroschistosomiasis mansoni can be classified into cerebral, spinal, and encephalomyelitic forms in the course of an acute or chronic infection.

REVIEW SUMMARY

We review the CNS involvement by S. mansoni infection with an emphasis on life cycle, epidemiology, pathophysiology and immunology, clinical manifestations, diagnostic criteria, differential diagnosis, current treatment guidelines, and prognosis.

CONCLUSIONS

Although an underreported CNS infection, found mainly in underdeveloped countries, neuroschistosomiasis mansoni still causes significant incapacity and morbidity. Hence, neurologists should become familiar with this infection worldwide and include it in the differential diagnosis of CNS involvement in travelers returning from endemic areas and in immigrants.

Travel-related infections in children

Malaria, diarrhea, respiratory infections, and cutaneous larva migrans are common travel-related infections observed in children and adolescents returning from trips to developing countries. Children visiting friends and relatives are at the highest risk because few visit travel clinics before travel, their stays are longer, and the sites they visit are more rural. Clinicians must be able to prepare their pediatric-age travelers before departure with preventive education, prophylactic and self-treating medications, and vaccinations. Familiarity with the clinical manifestations and treatment of travel-related infections will secure prompt and effective therapy.

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.

Schistosomiasis in areas of low endemicity: a new era in diagnosis

Parasitological detection of Schistosoma is the cornerstone of schistosomiasis diagnosis in areas of transmission worldwide. However, a steep decrease of sensitivity in low-endemicity areas (LEAs) compromises estimation of schistosomiasis. Despite the restricted utilization of molecular and immunodiagnostic techniques, recent improvements and advances have been contributing to change this scenario, especially in LEAs. Nonetheless, the main issue in a new era of diagnosis overcomes technical advances per se and relates to the loss of 'gold standards' in schistosomiasis diagnosis in LEAs. Here, we review and discuss the current role of molecular and immunodiagnostic methods in schistosomiasis management.

Parasitic liver disease in travelers

Liver disease is an important source of morbidity among ill returning travelers. Jaundice is one of the most common and obvious symptoms of liver disease, the differential diagnosis of which is extensive, especially in travelers. Jaundice in travelers can arise from both infectious and noninfectious causes. We herein summarize the most common parasitic etiologies that may lead to jaundice in the returned traveler, visitors of friends and relatives, or new immigrants, and describe the etiology, epidemiology, and pathogenesis of clinical features of each.