Case 28. Bilharziasis of colon (25 y-o M)
         
    Sigmoid colon biopsy from a student who traveled on foot through the African continent 3 years earlier    
         
   
Key words : Schistosoma haematobium, bilharziasis, pseudotubercle
   
     
 
     
Endoscopic observation reveals localized pallor and mild thickening of the colonic mucosa.   Localized submucosal fibrosis (pseudotubercle) is seen (HE, low power).
     
 
     
Foreign body granuloma is formed in the pseudotubercle (HE, high power). Miracidial nuclei are seen in some ova.   The 1:500 diluted patient's own serum specifically reacts with the ova (indirect immunoperoxidase).
     
 
     
Route of the transcontinental survival tour in Africa
The route mostly overlaps with the endemic area of bilharzian schistomiasis. A 10-minute contact with contaminated water may cause percutaneous infection of cercaria.
  Urine sediment
Hematuric urine contains number of ova of S. haematobium. A large-sized, spiculated ovum contains a living miracidium inside.
     
 
     
Urine cytology
Spiculated ova containing miracidium (Papanicolaou). The elongated ovum shows spiculation at one end and no operculum (Papanicolaou). Note the internal miracidium and eosinophilic host reaction.
  Urine cytology
Heavily ciliated miracidium with numerous nuclei (Giemsa). Centrifugation of urine artificially induces hatching of the miracidium.