E3- GI Protozoans Flashcards
How does Giardia lamblia present clinically?
- Watery diarrhea (NO blood)
- Vitamin B12 deficiency
What type of pathogen is Giardia lamblia?
Zoonotic flagellate GI protozoan
What population does Giardia lamblia most commonly affect?
Children
What stage of Giardia lambli exists freely in the small intestine and feeds on mucosal secretions?
Trophozoite
What is the morphology of the trophozoite stage of Giardia lamblia?
Tear drop shaped with 2 nuclei
Does the trophozoite stage of Giardia lamblia invade or destroy RBCs?
No (no blood in diarrhea)
What is the infectious stage of Giardia lamblia?
Cysts
What form of Giardia lamblia is passed into the environment?
Cysts
What is the morphology of the cysts stage of Giardia lamblia?
4 nuclei (1 cysts produces 2 trophozoites)
How is Giardia lamblia acquired?
Ingestion of cysts (infectious stage) from contaminated food or water with feces
Once Giardia lamblia cysts have been ingested, what occurs next?
- Ecystation and then the trophozoites move to into the small intestine to divide
- Trophozoites encyst in neutral pH and bile salts
- Cysts are passed into the environment (immediately infectious)
Why is Giardia lamblia highly contagious?
Cysts are immediately infectious
Infective dose = 10-25 cysts
>25 cysts = 100% infection rate
When are Giardia lamblia infections most prevalent?
June-october
Where geographically are Giardia lamblia infections most prevalent in the US?
Western states (Rocky mountains)
How is Giardia lamblia dx?
- Stool sample
- ELISA to detect GSA-65
What type of pathogen is Entamoena histalytica?
Protozoan that can result in colitis and liver abcesses
What is the etiology of amoebiasis?
Entamoena histalytica
What stage of Entamoena histalytica (amoebiasis) is invasive and ingest RBCs?
Trophozoite (blood in stool)
What is the morphology of the trophozoite stage of Entamoena histalytica (amoebiasis)?
- 1 nucleus
- Non-flagellated
- Pseudopod forming
What is the infectious stage of Entamoena histalytica (amoebiasis)?
Cysts
What is the morphology of the cysts stage of Entamoena histalytica (amoebiasis)?
4 nuceli (1 cyst produces 4 trophozoites)