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 non-endemic 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.