Balantidium coli – Trophozoite

February 13, 2021
  • Only ciliate that is pathogenic to human
  • Largest protozoan parasite in human
  • Habitat in human: Large intestine – caecum and colon
  • Normally parasitic in pigs
  • Trophozoites detected in faeces of infected human
Diagnostic Features
  • Size: 40-50 mm (range 50-70 µm or more)
  • Shape: oval
  • Longitudinal rows of cilia cover whole body
  • 01 large kidney shaped macronucleus; micronucleus not visible
  • Sometimes the cytostome (funnel-shaped mouth) also visible
  • Cytoplasm contains 1-2 contractile vacuoles and several food vacuoles
Magnification x4
Magnification x10
Magnification x40