Intro to Coccidian

• Coccidians


  • Spore-forming
  • Microscopic
  • Single-celled parasites

  
• Obligate intracellular protozoan


  Strictly need host cell to reproduce
• Coccidian infection


  • Infects gastrointestinal tract
  • Causes severe diarrhea
  • Stool as diagnostic specimen
• Diagnosis


  1. Stool culture: confirmatory

  2. Tissue biopsy: may be done
• Coccidiosis


  Disease caused by coccidians
• Coccidian hosts


  • Host specific, EXCEPT Toxoplasma gondii (all mammals)
• Coccidian infection in immunocompromised hosts


  • Opportunistic
  • AIDS patients
  • Transplant patients
  • Malnourished children
• Coccidian infection in immunocompetent individuals

  • May be asymptomatic
• Coccidian members


  • Isospora
  • Cyclospora
  • Cryptosporidium
  • Toxoplasma
  • Sarcocystis
• Coccidian life cycle


  1. Alternation of sexual and asexual multiplication

  2. Gametogony: producing microgamete and macrogamete

  3. Sporogony: microgamete fertilizes macrogamete producing oocyst with sporozoites

  4. Schizogony (Merogony): producing merozoites which become microgamete or macrogamete