›S. haematobium worms reside primarily in the pelvic venous plexus
›Acute disease — Katayama syndrome
›Immune complex-mediated hypersensitivity to migrating larvae
›Serum sickness-like illness 2 to 12 weeks post-exposure
›Eosinophilia, fever, urticaria, hepatosplenomegaly, lymphadenopathy
›More severe in previously unexposed travelers than endemic residents
›Chronic disease — granulomatous inflammation
›Adult worms lay eggs — S. haematobium produces 20 to 200 eggs per day
›Eggs deposited in bladder wall and urogenital tract
›Granulomatous inflammation surrounds eggs — T-cell mediated
›Progressive fibrosis and calcification of bladder, ureters, and genital tract
›Sandy patches — calcified eggs embedded in submucosal tissues
›Complications and carcinogenesis
›Obstructive uropathy from ureteral fibrosis — hydroureter and hydronephrosis
›Renal failure in advanced disease with cortical atrophy
›Squamous cell carcinoma via chronic inflammation and oxidative stress
›Upregulation of NF-kB, COX-2, and reactive oxygen species
›DNA damage from egg-derived molecules and host inflammatory response
›Female genital schistosomiasis — fibrosis of fallopian tubes, cervix, vagina
›Increased HIV susceptibility via mucosal disruption
›Infertility and ectopic pregnancy risk
›CNS disease — ectopic egg embolization to spinal cord or brain
›Granulomatous myelitis of conus medullaris most common spinal pattern
›Cerebral involvement less common
Therapeutic Considerations
›Evidence base for praziquantel
›Highly effective against adult worms — WHO essential medicine
›60 to 90% parasitological cure rates in clinical trials
›Mass drug administration programs reduce morbidity in endemic areas
›2022 WHO guidelines recommend preventive chemotherapy for school-age children
›No commercially available vaccine — praziquantel remains primary intervention
›Treatment monitoring
›Urine re-examination at 4 weeks post-treatment for persistent egg shedding
›Re-treat if eggs still present at 4 weeks
›Serology remains positive months to years — not useful for cure confirmation
›CAA or serum PCR are preferred post-treatment markers
›PCR negativity by approximately 12 months post-treatment indicates cure
›Reversibility of disease with treatment
›Early bladder wall thickening and hydronephrosis resolve well after treatment
›Calcifications may persist even after parasitological cure
›Advanced fibrosis, especially genital tract, may not fully resolve
›Bladder cancer risk persists even after treatment of infection
›Prevention and public health
›Avoid freshwater contact in endemic areas — no chemoprophylaxis available
›No licensed vaccine — multiple candidates in clinical trials
›Mass drug administration reduces prevalence and disease burden
›Safe water, sanitation, and hygiene (WASH) programs reduce transmission
›Screen household members and travel companions with shared exposure