Schistosoma Mansoni and Haematobium: Radiological Diagnostic Clues and Pathophysiology

Schistosomiasis (bilharzia) is a parasitic infection caused by trematodes of the Schistosoma genus and remains a significant health burden in endemic regions. Granulomatous host responses to deposited Schistosoma eggs in small veins and tissues result in progressive changes and characteristic imaging findings. This diagnostic radiological review synthesizes the published literature and highlights key and robust imaging findings that facilitate the diagnosis of Schistosoma mansoni and Schistosoma haematobium, with emphasis on modality-specific patterns and disease staging. Schistosoma mansoni primarily affects the liver, causing periportal fibrosis visible as “pipe-stem” echogenic thickening upon ultrasonography, which may progress to portal hypertension and chronic liver disease. Liver cirrhosis is the end-stage disease manifested as an irregular liver contour with surface nodularity and lobar redistribution as right lobe atrophy with left and/or caudate lobe hypertrophy. Schistosoma haematobium predominantly affects the genitourinary system, causing urinary bladder wall thickening and calcification. Early disease, within three months of infection, may present with fine calcification, firstly in the bladder base and then extending to the whole bladder and even to the ureters. Calcification appears as a line or two parallel lines on radiography and as a circle in axial computed tomography (CT) images, which is pathognomonic for early-stage Schistosomiasis. In contrast studies, including conventional urography and CT urography, Schistosoma eggs appear as bubble-like filling defects in the ureter, kidney, and bladder, manifested as ureteritis, pyelitis, and cystitis cystica. Late stages appear as coarse calcification, fibrosis, strictures, and reduced bladder capacity and are associated with an increased risk of bladder squamous cell carcinoma. Moreover, Schistosomiasis calcification can present in genital organs, especially in the seminal vesicles; in the prostate in males; and in the vulva, cervix, and perineum in females. Ultimately, Schistosoma mansoni and haematobium eggs can reach the spinal cord, leading to acute myelopathy with paraparesis, urinary retention, or paraplegia. Recognition of characteristic imaging patterns of Schistosomiasis is essential for early diagnosis, accurate staging, and prevention of long-term complications.