Schistosomiasis presenting in travellers: a 15 year observational study at the Hospital for Tropical Diseases, London

Coltart, Cordelia E M; Chew, Anastasia; Storrar, Neill; Armstrong, Margaret; Suff, Natalie; Morris, Leila; Chiodini, Peter L.; Whitty, Christopher J M

doi:10.1093/trstmh/tru195

Cited by 47 publications

(43 citation statements)

References 17 publications

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“…Serology for egg antigen is the standard screening method, which has a sensitivity of over 90% for travellers and slightly less for people originally from endemic countries. 6 …”

Section: Diagnosismentioning

confidence: 99%

Schistosomiasis in non-endemic countries

Coltart

Whitty

2015

Clinical Medicine

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Schistosomiasis in non-endemic countriesSchistosomiasis is one of the major parasitic diseases of the tropics, causing acute and long-term clinical syndromes. Almost all schistosomiasis is now imported from subSaharan Africa. This article summarises the aetiology, clinical presentation, diagnosis and management of schistosomiaisis for clinicians in non-endemic countries.Schistosomiasis (also known as bilharzia) is one of the major parasitic diseases of the tropics, with more than 240 million people in over 70 countries infected. 1 90% of these cases are in sub-Saharan Africa and almost all schistosomiasis seen in the UK is now imported from there. Rare cases are still imported from Asia and Latin America, although the incidence in these continents is reducing as a result of successful schistosomiasis control programmes, most notably in China.Schistosomiasis infection in returning travellers is one of the most common imported tropical infections with potentially serious acute and long-term complications. These complications are preventable if infection is identified early and treated. This article is written for clinicians in non-endemic countries where patients generally have light infections, and summarises the epidemiology, transmission, clinical features, diagnosis and management of schistosomiasis Transmission/life cycleThe life cycle of the schistosomiasis fl uke is shown in Fig 1. Schistosomiasis infection invariably comes from contact with fresh water, usually by swimming or washing. Travellers may not remember their freshwater contact, so this is not a reliable screening question; in asymptomatic travellers from Africa, up to 11% have been reported as infected. 2,3 Two species of human schistosomiasis predominate; Schistosomiasis haematobium, which mainly affects the bladder and urogenital system, and S mansoni, which mainly affects the liver and gut. The much rarer species, which are S intercalatum, S japonicum and S mekongi, all present similarly to S mansoni, with the latter two being found in Asia.

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“…Serology for egg antigen is the standard screening method, which has a sensitivity of over 90% for travellers and slightly less for people originally from endemic countries. 6 …”

Section: Diagnosismentioning

confidence: 99%

Schistosomiasis in non-endemic countries

Coltart

Whitty

2015

Clinical Medicine

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“…The diagnosis of schistosomiasis by detection of specific antibodies (with tests generally based on crude antigens of S . mansoni ) is more sensitive than microscopy, particularly in light infections [26,28]. However, commercial serologic tests for schistosomiasis have a sub-optimal sensitivity too, in particular for S .…”

Section: Introductionmentioning

confidence: 99%

Accuracy of parasitological and immunological tests for the screening of human schistosomiasis in immigrants and refugees from African countries: An approach with Latent Class Analysis

et al. 2017

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BackgroundSchistosomiasis is a neglected infection affecting millions of people, mostly living in sub-Saharan Africa. Morbidity and mortality due to chronic infection are relevant, although schistosomiasis is often clinically silent. Different diagnostic tests have been implemented in order to improve screening and diagnosis, that traditionally rely on parasitological tests with low sensitivity. Aim of this study was to evaluate the accuracy of different tests for the screening of schistosomiasis in African migrants, in a non endemic setting.Methodology/Principal findingsA retrospective study was conducted on 373 patients screened at the Centre for Tropical Diseases (CTD) in Negrar, Verona, Italy. Biological samples were tested with: stool/urine microscopy, Circulating Cathodic Antigen (CCA) dipstick test, ELISA, Western blot, immune-chromatographic test (ICT). Test accuracy and predictive values of the immunological tests were assessed primarily on the basis of the results of microscopy (primary reference standard): ICT and WB resulted the test with highest sensitivity (94% and 92%, respectively), with a high NPV (98%). CCA showed the highest specificity (93%), but low sensitivity (48%). The analysis was conducted also using a composite reference standard, CRS (patients classified as infected in case of positive microscopy and/or at least 2 concordant positive immunological tests) and Latent Class Analysis (LCA). The latter two models demonstrated excellent agreement (Cohen’s kappa: 0.92) for the classification of the results. In fact, they both confirmed ICT as the test with the highest sensitivity (96%) and NPV (97%), moreover PPV was reasonably good (78% and 72% according to CRS and LCA, respectively). ELISA resulted the most specific immunological test (over 99%). The ICT appears to be a suitable screening test, even when used alone.ConclusionsThe rapid test ICT was the most sensitive test, with the potential of being used as a single screening test for African migrants.

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“…This resulted in a number of local people and tourists becoming infected with urogenital schistosomiasis [9–11]. Previous studies have revealed that the schistosomiasis prevalence rate in sub-Saharan African immigrants during 2000–2009 in Spain was ~5.9% ( n = 317), while the Hospital for Tropical Diseases in the United Kingdom diagnosed 1020 schistosomiasis cases in travellers returning from Africa between 1997 to 2012; S. haematobium was the predominant species in those with schistosomiasis confirmed by microscopy (74.2%, 204/252) [13, 14]. …”

Section: Introductionmentioning

confidence: 99%

Distribution and current infection status of Biomphalaria straminea in Hong Kong

et al. 2017

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BackgroundSchistosomiasis, also generally known as snail fever, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. In Hong Kong and mainland China, the freshwater snail Biomphalaria straminea has been introduced and has the potential to transmit intestinal schistosomiasis caused by S. mansoni, a parasite of man which has a wide distribution in Africa and parts of the New World, especially Brazil. The first identification of B. straminea in Hong Kong dates back to the 1970s, and its geographical distribution, phylogenetic relationships, and infection status have not been updated for more than 30 years. Thus, this study aims to reveal the distribution and current infection status of B. straminea in contemporary Hong Kong.MethodsSnails were collected from different parts of Hong Kong from July 2016 to January 2017. Both anatomical and molecular methods were applied to identify B. straminea. Cytochrome c oxidase subunit 1 (cox1), internal transcribed spacer 1 (ITS1), 5.8S rDNA, internal transcribed spacer 2 (ITS2), and 16S ribosomal DNA (rDNA) were sequenced from individual snails and analyzed. To detect the presence of S. mansoni, both biopsy and PCR analyses were carried out.ResultsUsing both anatomical and molecular analyses, this study demonstrated the existence of black- and red-coloured shell B. straminea in different districts in the New Territories in Hong Kong, including places close to the mainland China border. None of the B. straminea (n = 87) investigated were found to be infected with S. mansoni when tested by biopsy and PCR. The Hong Kong B. straminea are genetically indistinguishable, based on the chosen molecular markers (cox1, ITS1-5.8S-ITS2, and 16S rDNA), and are similar to those obtained in mainland China and South America.Conclusion Biomphalaria straminea is now well established in freshwater habitats in Hong Kong. No evidence of infection with S. mansoni has been found. Surveillance should be continued to monitor and better understand this schistosomiasis intermediate host in mainland China and Hong Kong.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2285-3) contains supplementary material, which is available to authorized users.

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Schistosomiasis presenting in travellers: a 15 year observational study at the Hospital for Tropical Diseases, London

Cited by 47 publications

References 17 publications

Schistosomiasis in non-endemic countries

Schistosomiasis in non-endemic countries

Accuracy of parasitological and immunological tests for the screening of human schistosomiasis in immigrants and refugees from African countries: An approach with Latent Class Analysis

Distribution and current infection status of Biomphalaria straminea in Hong Kong

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