Ultrasound and intestinal lesions in Schistosoma mansoni infection: A case-control pilot study outside endemic areas

BACKGROUND: Infection with Schistosoma mansoni is a major cause of morbidity and mortality in endemic areas, and is increasingly diagnosed in migrants and travellers outside transmission areas. Markers for the assessment of morbidity and impact of control programs in endemic areas and for the clinical management of patients in the clinical setting are scant, especially for intestinal involvement. Ultrasonography is well established to evaluate hepatosplenic pathology; on the contrary, ultrasound evaluation of intestinal schistosomiasis is virtually unexplored. In this pilot study, we aimed to describe and evaluate the accuracy of unenhanced intestinal ultrasound for morbidity due to intestinal S. mansoni infection. METHODOLOGY/PRINCIPAL FINDINGS: We performed a blind case-control study of unenhanced intestinal ultrasound on 107 adults accessing the outpatient clinic of our Centre for Tropical Diseases between January-July 2018 as part of a screening for tropical diseases in migrants and travellers returning from endemic areas. Other clinical and laboratory data were obtained routine examination reports. We could not find any overtly pathological thickness of the gut wall in the sigma, proximal ascending colon, and terminal ileum, in patients with S. mansoni infection (n = 17), S. haematobium infection (n = 7), positive anti-Schistosoma serology (n = 31), and uninfected individuals (n = 52), with no difference among groups as assessed by ANOVA. No polyps or other intestinal abnormalities were visualized. There was no significant change in gut wall thickness one month after treatment with praziquantel in patients with S. mansoni infection (n = 11). CONCLUSIONS/SIGNIFICANCE: Our preliminary results suggest that intestinal ultrasound might not be a sensitive tool for detecting minor intestinal morbidity due to schistosomiasis. Further studies in a hospital setting comparing colonoscopy and ultrasonography may be envisaged; in endemic areas, further studies are needed to describe and assess the usefulness of intestinal ultrasound in patients stratified by infection intensity and compared with markers such as calprotectin and fecal occult blood.