para trematoswa

• Trematodes


  • Flat, unsegmented worms
  • Leaf-like organisms
  • Incomplete digestive tract
  • Oral sucker
  • Ventral sucker or acetabulum
  • Genital sucker (only heterophyids)

  
• All trematodes are hermaphroditic
• All trematodes require two intermediate hosts
• Eggs of all trematodes are operculated
• The infective stage is metacercariae
• Schistosomes


  Trematodes that are an exception to the general rules
• Classification of medically important trematodes

  • Phylum Platyhelminthes
  • Class Trematoda
  • Subclass Digenea
• Classification of trematode ova (mature)

  • Clonorchis
  • Heterophyids
  • Opisthorchis
• Classification of trematode ova (immature)

  • Fasciola
  • Fasciolopsis
  • Echinostoma
  • Paragonimus
  • Schistosoma
• General life cycle of trematodes

  1. Egg

  2. Miracidium

  3. Sporocyst

  4. Cercaria

  5. Schistosomulae
• Classification of trematodes based on location in man

  • Blood flukes
  • Intestinal flukes
  • Liver flukes
  • Lung flukes
• Schistosoma japonicum


  • Parasitizes portal vein and its branches
  • Each female fluke deposits 500-2000 immature eggs/day
• Schistosoma japonicum adult


  Males have a gynecophoral canal which receives the female during copulation
• Schistosoma japonicum ova


  • Ovoidal, rounded or pear-shaped
  • Thin shell
  • Pale yellow
  • Curved hook / spine or lateral knob
  • Laid in the multicellular stage and embryonate within 10-12 days
• Schistosome miracidium


  • Hatches from the egg in slightly alkaline clean water with a temp. between 25 0C to 310C
  • Free swimming ciliated embryo liberated from the egg
  • Phototactic
  • Infect snails
• Schistosome cercaria


  • Emerges from daughter sporocysts
  • Escapes from the snail
  • Has a body and a forked tail
  • Infects man by skin penetration
• Schistosomulae


  • Develops from cercaria after skin penetration
  • Adapted to survive in serum or physiologic saline at 37 0C
  • Enter the pleural cavity---diaphragm---peritoneal space---penetrate the liver to reach the intrahepatic portions of the portal vein
• Schistosoma mansoni


  Female inside the gynecophoral canal of male
• Schistosoma mansoni ova


  With Lateral spine
• Schistosoma haematobium ova


  • Note the terminal spine
  • Eliminated with urine
• Differentiating features of schistosomes

  • Testes (male)
  • Ovary (Female)
  • Intestine
  • Egg
  • Intermediate Host
  • Definitive Host
• Pathogenesis and clinical manifestations of schistosomiasis

  • Host granulomatous reaction to eggs
  • Pneumonitis due to schistosomulae in the lungs
  • Hepatosplenic disease
  • Colonic schistosomiasis
  • Cerebral schistosomiasis
• Schistosomiasis diagnosis


  • Rectal biopsy
  • Stool Examination Techniques
  • Immunodiagnosis
• Fasciola hepatica / Fasciola gigantica


  • Large, flat, brownish
  • 3 x 1.5 cm
  • With oral sucker and ventral sucker
  • Integument covered with scales; posterior end surface smooth
  • Alimentary system inverted Y-branched ceca with lateral branches
• Fasciola hepatica / Fasciola gigantica ova


  • Operculated
  • 140-150 x 65-90 micra (hepatica)
  • 160-190 x 70-90 micra (gigantica)
  • Light yellow: bile stained
  • Transparent with thin double walls
  • Contain lecithin granules (immature)
• Fasciola hepatica / Fasciola gigantica intermediate hosts

  • 1st IH: Lymnaea philippinensis, Lymnaea swinhoei
  • 2nd IH: Ipomoea obscura (Kangkong), Nasturtium officinale (water cress)
• Fasciola species laboratory diagnosis

  • Microscopy
  • Serologic tests
  • RFLP (Restriction Fragment Length Polymorphism)
  • PCR
• Clonorchis sinensis (Chinese Liver Fluke)

  • Adult: size 11-20 um x 3-4.5um, Lanceolate, Translucent and brownish in color
  • Egg: Transparent, up to 6,000 worms present with a daily output of about 1,000 eggs/microliter of bile or 600 per gram of feces, Bile stained with a smooth outer coat and is flask-shape, Measures 29 um x 16 um, There are fully developed with miracidia and possess prominent opercular shoulders
• Clonorchis sinensis intermediate hosts

  • 1st IH: Bulimus, Parafossarulus, Semiculcoapira
• Hepatica ova


  First intermediate host
• First intermediate host


  • Lymnaea philippinensis
  • Lymnaea swinhoei
• Second intermediate host


  • Ipomoea obscura (Kangkong)
  • Nasturtium officinale (water cress)
• Fasciola hepatica / Fasciola gigantica

  Fasciola species
• Laboratory diagnosis methods


  • Microscopy
  • Serologic tests
  • Restriction Fragment Length Polymorphism (RFLP)
  • PCR
• Serologic tests have low specificity because of cross reactivity with antigens of other parasites
• Clonorchis sinensis


  Chinese Liver Fluke
• Adult Clonorchis sinensis


  • Size 11-20 um x 3-4.5um
  • Lanceolate
  • Translucent and brownish in color
• Clonorchis sinensis egg


  • Wet mounts: transparent
  • Up to 6,000 worms present with a daily output of about 1,000 eggs/microliter of bile or 600 per gram of feces
  • Bile stained with a smooth outer coat and is flask-shape
  • Fully developed with miracidia and possess prominent opercular shoulders
  • Measures 29 um x 16 um

  
• First intermediate host of Clonorchis sinensis

  • Bulimus
  • Parafossarulus
  • Semiculcoapira
  • Alosinma
  • Melanoides
• Second intermediate host of Clonorchis sinensis

  • Fish of the Family Cyprinidae