Trematodes

• What are trematodes also known as?

  Flukes
• What is a primary characteristic of trematodes?

  They are unsegmented, flat, and broad
• How are trematodes classified?

  According to their habitat inside the human body
• What are the general characteristics of trematodes (except Schistosomes)?

  • Monoecious (hermaphroditic)
  • Primary and secondary intermediate hosts
  • Metacercaria is the infective stage
  • Ingestion is the mode of transmission
  • Eggs are operculated
  • Leaf-like shape
  • Two suckers: oral and ventral
• What does it mean for trematodes to be hermaphroditic?

  They have both male and female reproductive organs
• What is the role of the intermediate host in trematodes' life cycle?

  They pass their larval stage in freshwater mollusks
• What is the infective stage of trematodes?

  Metacercaria
• How do trematodes typically enter the human body?

  Through ingestion
• What shape are trematode eggs?

  Operculated and oval-shaped
• What are the two types of suckers found in trematodes?

  Oral sucker and ventral sucker
• What is the unique characteristic of Heterophyes?

  It has a genital sucker or gonotyl
• What are the differences between Schistosomes and other trematodes?

  • Schistosomes are dioecious, others are monoecious
  • Schistosomes have one intermediate host, others have two
  • Schistosomes have cercaria, others have metacercaria
  • Schistosomes enter through skin penetration, others through ingestion
  • Schistosomes are elongated, others are leaf-like
• What is the common name for Fasciola hepatica?

  Sheep liver fluke
• What is the final host for Fasciola hepatica?

  Sheep
• What is the first intermediate host for Fasciola hepatica?

  Lymnaea philippinensis (snails)
• What is the infective stage of Fasciola hepatica?

  Metacercaria
• What pathology is associated with Fasciola hepatica?

  Fascioliasis, liver rot, liver atrophy
• What is the drug of choice for Fasciola hepatica?

  Bithionol
• What distinguishes Fasciola hepatica from Fasciola gigantica?

  1. hepatica has a prominent cephalic cone
• What are the laboratory diagnosis methods for Fasciola hepatica?

  • Stool exam
  • Liver biopsy
  • PCR
• What are the general characteristics of Clonorchis sinensis, Opistorchis felineus, and Opistorchis viverrini?

  • Common names: Oriental liver fluke, Chinese liver fluke, Cat liver fluke
  • Final host: Man and fish-eating vertebrates
  • Infective stage: Metacercaria
  • Pathology: Bile duct obstruction, liver cancer
• What is the common name for Fasciola lanceolata?

  Lancet fluke
• What is the first intermediate host for Fasciola lanceolata?

  Cionella lubrica (snails)
• What is the habitat of Fasciola lanceolata?

  Biliary tree of herbivores
• What is the common name for Eurytrema pancreaticum?

  Pancreatic fluke
• What is the final host for Eurytrema pancreaticum?

  Hogs and herbivores
• What is the pathology associated with Eurytrema pancreaticum?

  Destruction of the pancreas
• What is the common name for Fasciolopsis buski?

  Giant intestinal fluke
• What is the habitat of Fasciolopsis buski?

  Small intestine (duodenum and jejunum)
• What is the first intermediate host for Fasciolopsis buski?

  Semetina spp. (snails)
• What is the second intermediate host for Fasciolopsis buski?

  Water plants like Trapa and Eichhornia
• What is the laboratory diagnosis method for Fasciolopsis buski?

  Stool exam (eggs)
• What are the prevention and control measures for trematodes?

  • Proper food preparation and handling
  • Killing parasites in reservoir hosts
  • Vaccination of animals with defined Fasciola antigens
  • Health education
• What are the laboratory diagnosis methods for Clonorchis sinensis, Opistorchis felineus, and Opistorchis viverrini?

  • Stool exam
  • Serological tests
  • Molecular tests
  • Cholangiography
• What are the life cycle stages of trematodes?

  • Miracidium
  • Sporocyst
  • Rediae
  • Cercariae
  • Metacercariae
• What are the symptoms of human fascioliasis during the acute phase?

  • Asymptomatic or mild symptoms
  • Fever
  • Abdominal pain
  • Hyper eosinophilia
• What are the symptoms of human fascioliasis during the chronic phase?

  • Diagnosed through surgical operation
  • Parasites reach bile ducts
  • Possible obstruction and inflammation
• What is "Halzoun" or "Marrara"?

  • Pharyngeal suffocation
  • Temporary lodgment of fluke in pharynx
  • Known as "Halzoun" in Lebanon and "Marrara" in Sudan
• What are the common laboratory diagnosis methods for trematodes?

  • Stool exam
  • Recovery of adult flukes
  • Liver biopsy
  • Molecular methods (PCR, ELISA)
  • Radiologic examination (Sonography, CT, ERCP)
• What are the common names for Clonorchis sinensis, Opistorchis felineus, and Opistorchis viverrini?

  • Clonorchis sinensis: Oriental liver fluke
  • Opistorchis felineus: Chinese liver fluke
  • Opistorchis viverrini: Cat liver fluke