Class Trematoda

• Phylum of Flukes

  • Platyhelminthes
• Order: Cyclophyllidea


  Characteristics: Scolex globular with cuplike suckers
• Order: Pseudophyllidea


  Characteristics: Scolex spatulate with bothria
• Species under Cyclophyllidea which require vertebrates as intermediate hosts:


  • Taenia solium
  • Taenia saginata
• Species under Cyclophyllidea which may or may not require intermediate hosts:


  • Hymenolepis nana
• Species under Cyclophyllidea which infect man in their larval stage


  • Echinococcus granulosus
  • Echinococcus multilocularis
  • Taenia solium
• Species of Class Trematoda (Flukes) which inhabit the portal bloodstream of vertebrate:


  • Schistosoma japonicum
  • Schistosoma mansoni
  • Schistosoma haematobium
• Species of Class Trematoda (Flukes) which inhabit the liver of vertebrates:


  • Fasciola hepatica
  • Clonorchis sinensis
  • Opistorchis felineus
• Species of Class Trematoda (Flukes) which inhabit the small intestines of vertebrates


  • Fasciolopsis buski
  • Echinostoma ilocanum
  • Heterophyid group
• Species of Class Trematoda (Flukes) which inhabit the lungs of vertebrates:


  • Paragonimus westermani
• TREMATODA: General Features

  • Flat leaf-like bodies
  • With oral and ventral suckers and a blind sac-like gut
  • Acoelomate
  • Dorsoventrally flattened with bilateral symmetry
  • Gliding or creeping motion
  • Hermaphroditic
• TREMATODA: Life Cycle


  1. Egg
  2. Miracidium
  3. Sporocyst
  4. Redia
  5. Cercaria
  6. Metacercaria
  7. Adult
• TREMATODES: Blood Flukes


  • Schistosoma mansoni - causes intestinal schistosomiasis
  • Schistosoma haematobium - causes visceral shcistosomiasis
  • Schistosoma japonicum - causes intestinal schistosomiasis
  • Schistosoma intercalatum - causes intestinal schistosomiasis
  • Schistosoma mekongi - causes intestinal schistosomiasis
• Schistosoma japonicum


  • Male (12-20mm), female (15-26mm)- lays 500-3500 eggs daily
  • With incomplete excretory system
  • With large suckers and gonophore
  • Ingest RBC, break globulin & hemoglobin
• Epidemiology: Schistosoma species


  • Schistosoma mansoni - Africa, South America, Carribean
  • Schistosoma haematobium - Africa & Egypt, Middle East
  • Schistosoma japonicum - Indonesia, parts of China, & Southeast Asia
  • Schistosoma mekongi - Cambodia & Laos
  • Schistosoma interlacatum - Central and West Africa
• Epidemiology - endemic in the Philippines


  • Sorsogon, Oriental Mindoro, Samar, Leyte, Bohol, All provinces of Mindanao except Oriental Misamis
• Intermediate host of Schistosoma japonicum (in PH setting)

  Oncomelania quadrasi
• Prevention and Control


  1. Avoid urination and defecation in canals

  2. Avoid swimming in places with known occurrences of schistosomiasis

  3. Drink safe water

  4. Boil drinking or bathing water

  5. Snail control

  6. Molluscides
• TREMATODES: Liver Flukes


  • Clonorchis sinensis (Chinese liver fluke)
  • Fasciola hepatica (sheep liver fluke)
  • Fasciola gigantica (cattle liver fluke)
• Fasciola hepatica & F. gigantica: General Features


  • Digenetic (subclass Digenea)
  • With large and broad, flat bodies (20-50mm x 6-12mm)
  • Cephalic cone
  • Suckers
  • Branched testes; dendritic ovaries
• Clinical Manifestations of Fascioliasis


  • Hepatic fever, right upper quadrant abdominal pain
  • Traumatic and necrotic lesions
  • Hepatomegaly
  • Hypereosinophilia
  • Biliary obstruction or cirrhosis
  • Liver atrophy
  • Formation of abscess
• Diagnosis & Treatment of Fascioliasis


  • Microscopy
  • Serological tests
  • Radiology
  • Rapid PCR-RFLPs
  • Bithionol
  • Triclabendazole
• Epidemiologyof Fasciola gigantica and Fasciola hepatica


  • Worldwide
  • Philippines: F. gigantica is greater
• Prevention & Control


  1. Proper washing and cooking of vegetables

  2. Boiling of water

  3. Vaccination of animals
• Other Trematodes


  • Paragonimus westermani (Lung Fluke)
  • Echinostoma ilocanum
  • Opistorchis sp.
• Schistosomiasis

  • It is an acute and chronic disease caused by parasitic worms called trematodes (or blood flukes)
  • Schistosoma Japonicum (endemic to PH) is transmitted by a tiny snail called Oncomelania quadrasi
  • There is a high prevalence in Bicol, Samar & Leyte, and Davao.
  • In the Philippines, the total population at risk is approximately 12.4 million with 2.6 million individuals directly exposed to the disease.
• Early symptoms of Schistosomiasis japonicum

  1. Stomach Pain
  2. Low-grade fever
  3. Loose Bowel Movement
  4. Bloody Mucoid Stools
• Late Symptoms of Schistosomiasis Japonicum Infection

  1. Enlargement of liver and spleen
  2. Bulging of abdomen
  3. emaciation
• Diagnosis and Treatment of Schistosomiasis

  • Microscopic Tests
  • Serological Tests
  • Praziquantel (medication)
• Prevention and Control of Schistosomiasis

  1. Avoid urination and defecation in canals
  2. Avoid swimming in places with known occurrences of schistosomiasis
  3. Drink safe water
  4. Boil Drinking or bathing water
  5. Snail control
  6. Molluscides
• Liver Flukes' Important Species

  1. Clonorchis sinensis (Chinese Liver Fluke)
  2. Fasciola hepatica hepatic(sheep liver fluke)
  3. Fasciola gigantica (cattle liver fluke)
• Fasciola hepatica

  • commonly called as 'sheep liver fluke'
  • In sheep, the migratory phase of the parasite produces severe parenchymal diseases of the liver for which the parasite is called sheep liver fluke and the disease is known as liver rot