A 40-year-old rice-farmer from Tamil Nadu presents with haematuria and terminal dysuria. Urine microscopy shows eggs with a terminal spine. The diagnosis is confirmed by detecting circulating cathodic antigen (CCA) in urine. Which trematode and which intermediate host is involved?
- A Schistosoma mansoni; freshwater snail Biomphalaria species
- B Schistosoma japonicum; Oncomelania snail
- C Fasciola hepatica; freshwater snail Lymnaea species
- D Schistosoma haematobium; freshwater snail Bulinus species ✓
Explanation
Schistosoma haematobium causes urogenital schistosomiasis with terminal haematuria; its eggs have a terminal spine (vs. lateral spine in S. mansoni). The intermediate host is the freshwater snail Bulinus species. Circulating cathodic antigen (CCA) and circulating anodic antigen (CAA) detection in urine are point-of-care diagnostics now preferred over Kato-Katz stool microscopy. Treatment is praziquantel 40 mg/kg as a single dose. S. mansoni causes intestinal and hepatosplenic disease; S. japonicum is the most pathogenic species causing hepatosplenic disease in East Asia.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.