GI protozoa Flashcards
What causes amebiasis?
Entamoeba histolytica
What is the transmissible form of entamoeba histolytica?
Cyst form
What is the pathogenesis of entamoeba histolytica?
- Cyst form breaks out and invades wall of colon 2. Can remain in lumen to replicate or penetrate intestinal wall to go to brain, liver, etc
Which pathogen causes characteristic flask shaped lesions?
Entamoeba histolytica
Who is more infectious in an entamoeba histolytica infection - symptomatic or asymptomatic person?
Asymptomatic - more cysts in stool
What are the symptoms of symptomatic entamoeba histolytica infection?
Bloody, mucousy diarrhea (fever is rare)
What is the route of transmission for entamoeba histolytica?
Fecal-oral, ingestion of cysts
What are the properties of invasive amebiasis?
- Penetration of intestinal wall by trophozoites 2. Flask shaped lesion 3. Spread via blood stream - liver abscess, abdominal pain, fever, increased WC
In amebiasis infection, solid stool contains more cysts or trophozoites?
Cysts
What is the cause of giardiasis?
Giardia lamblia
What is the infective stage in giardia lamblia?
Cyst
What is the lifecycle of giardia lamblia?
- Excysts in duodenum 2. Multiples by longitudinal binary fission 3. Trophozoites on mucosa of duodenum 4. Trophozoites and cysts shed in stool 5. Trophozoites disintegrate, cysts reinfect
What are the stool characteristics for giardiasis infection?
- Greasy, foul smelling floating stools 2. No blood 3. No fever
What are the properties of symptomatic vs asymptomatic individuals with giardiasis infection?
- Symptomatic - frank abdominal distress, likely passing trophozoites in stool 2. Asymptomatic - tend to pass cyst form
What causes balantidiasis?
Balantidium coli