Balantidium

• Balantidium coli


  Also known as Paramecium coli

  
• Balantidium coli


  • Large ciliated protozoan parasite
  • ONLY ciliate pathologic to man
  • Largest protozoan parasitizing man

  
• Natural habitat


  Large intestine feeding on bacteria, mucus secretion, cell debris

  
• Reservoir host


  Pigs (originally associated with pigs)
• Balantidiasis


  Common among pig farmers and slaughterhouse workers
• Cyst


  • 40 - 60 um
  • Spherical to ovoid
  • Covered with thick cell wall (double walled)
  • Encystation does not result in an increase number of nuclei
• Trophozoite


  • 30 - 150 um long, 25 - 120 um wide
  • Covered with cilia for locomotion
  • Cytostome - mouth
  • Cytopyge - excretion
  • 2 nuclei (bean-shaped nucleus and micronucleus)
  • 2 contractile granules - osmoregulatory
  • Mucocysts - beneath the cell membrane
  • Ciliated with rotary, boring motion
• Trophozoite


  • Ovoid, covered with uniformly-sized cilia
  • Cytostome on anterior end
  • Posteriorly: Broadly rounded, contains cytopyge
  • Cytoplasm contains food vacuoles and two nuclei: Macronucleus and micronucleus

  
• Life Cycle of Balantidium coli


  1. The cyst is the infective stage and is acquired through ingestion of contaminated food and water

  2. Incubation Period: 4 - 5 days

  3. Infection associated with alcoholism, poor nutritional status, chronic diseases, poor hygeine

  4. Reservoir host: pigs or swine

  5. Cyst can often be demonstrated in formed stool and trophozoites can be demonstrated in semi-formed or watery stool