Severe complications of imported schistosomiasis, Spain: A retrospective observational study

Background: Chronic schistosomiasis silently leads to severe organ-specific disorders, such as hydroureter, bladder cancer or portal hypertension in around 10% of infected people in endemic zones. However, in nonendemic areas, information on schistosomiasis' severe complications and their actual prevalence is scarce because diagnosis is usually reached when such complications are well established. Methods: Retrospective observational study of data obtained from a screening protocol designed for sub-Saharan migrants including search for stool parasites and schistosoma serology. After screening 3090 sub-Saharans, 326 (10.5%) confirmed cases of schistosomiasis were found, based on detection of ova in feces, urine or in biopsy samples. Another 830 patients (26.9%) were diagnosed of probable schistosomiasis (positive serology and/or suggestive imaging findings). Results: Only patients with confirmed schistosomiasis were included in the final analysis. Among them, 13 (4%) presented severe complications at the time of diagnosis. Depending on the location, they account for 5% of patients with hepatointestinal schistosomiasis and 3.5% of patients with urogenital infection. Conclusions: Targeted systematic screening could reduce the prevalence of severe complications by enabling early diagnosis and treatment. Having indigenous transmission been demonstrated in southern Europe, prevention of future cases in non-endemic countries might be another sound reason supporting such screening.