Schistosoma spp.

• Schistosoma japonicum otherwise known as Oriental blood fluke
• Infects humans and all other kinds of mammals

  S. japonicum
• Habitat of Adult Worm of S. japonicum - Superior mesenteric vein
• Intermediate host of S. japonicum - Oncomelania quadrasi
• Characteristic of egg of S. japonicum - Small lateral knob/spine
• Otherwise known as Manson’s fluke

  S. mansoni
• Smallest of the schistosoma species

  S. mansoni
• Habitat of Adult Worm of S. mansoni - Inferior mesenteric vein
• Intermediate host of S. mansoni - Biomphalaria spp.
• Egg of S. mansoni - Prominent lateral spine
• Schistosoma haematobium otherwise known as Vesical blood fluke
• Habitat of Adult Worm of S. haematobium - Vesical plexus
• Intermediate hosts of S. haematobium - Bulinus, Physopsis, Biomphalaria
• Egg of S. haematobium - Terminal spine
• Egg deposition causes the main pathology
• Adult worm

  • Exhibit “Immunologic camouflage”
  • Adult worms will not evoke immune response
• PATHOGENESIS includes Skin Penetration, Schistosomula migration, Adult worm Immunologic camouflage, and host granulomatous reaction to eggs
• Caused by cercarial penetration


  Swimmer’s Itch (Cercarial dermatitis)
• Caused by the schistosomula migration

  Katayama fever (Katayama syndrome)
• • Gold standard; most specific test
  • Direct visualization of schistosome eggs via stool or urine
  • Disadvantage: Can give FALSE NEGATIVE results even in ACTIVE infection

  Kato-Katz
• • One of the most sensitive diagnostic technique
  • Disadvantage: Cannot distinguish between treated and untreated infection

  TISSUE BIOPSY (Rectal Snips or Imprint)
• IMMUNODIAGNOSTICS

  Intradermal, Indirect Hemagglutination, COPT, ELISA
• • All tests are sensitive but are not useful in distinguishing active from treated infection
  • All are not routinely used

  IMMUNODIAGNOSTICS
• • Serum (antibody) of Schistosoma-infected individual is made to react with Schistosoma egg (antigen)
  • (+) bleb formation
  • Done in patients who are stool negative but highly suspicious for schistosomiasis


  Circumoval Precipitin Test (COPT)
• ● Drug of choice

  ● Not ideally given during the Schistosomule stage due to its low efficacy and

  possibility of worsening of symptoms

  PRAZIQUANTEL
• • Shown to be effective in decreasing S. japonicum infection when used as a preexposure prophylaxis
  • Effective against juvenile worm stage
  • Resistance against malaria is a main drawback

  ARTEMISININS (Artemether)
• PREVENTION AND CONTROL includes

  ● CHEMOTHERAPY (Mass Drug Administration by DOH)

  ● SNAIL CONTROL