Intestinal Protozoa Flashcards
What are the intestinal protozoa?
- Entamoeba histolytica
- Giardia lamblia
- Trichomonas vaginalis (according to Minchella)
- Cryptosporidium parvum
Introduction of Entamoeba histolytica to human?
- Cyst in contaminated food/drink
- Small intestine (form metacyst)
- Large intestine (8 trophozoites) - colonize mucosa
How does Entamoeba histolytica cause ambebiasis?
Bloody amoebic dysentery
- Invade cells –> flask-shaped ulcer
- Get in submucosa and invade blood vessels
1% goes to liver
Where is the liver abscess for Entamoeba histolytica located?
Right lobe. Filled with fluid (anchovy paste). Enters via hepatic portal system.
If you’re asymptomatic, trophs will be in ______
cyst form in large intestine
Entamoeba histolytica disease course:
2-3 weeks post-exposure
- Cramps, flatulence, diarrhea, NO FEVER
- Abdominal pain, lesions
- Dehydration
If acute
- Severe cramps, tons of shit, pain, FEVER, colon damage
- RUQ liver damage
Diagnosis of Entamoeba histolytica?
Demonstrate cyst in stools or troph in diarrhea
Culture parasite, PCR
Treatment of Entamoeba histolytica?
Metronidazole (if side effects - tetracycline)
Eliminate cysts with Iodoquinol or Paramycin (Paromomycin?)
Life cycle of Giardia lamblia?
Ingested as cysts in stools –> fecal/oral to duodenum (trophs)
Trophs go to cyst form as they move to large intestine, where they leave as feces
How does Giardia lamblia cause pathogenesis?
Trophs attach to epithelial layers and interfere with fat absorption
- Belching/flatulence
- Diarrhea
- Nausea
- Weight loss
- Intestinal cramps
Reservoir hosts of Giardia?
Dogs, muskrats
Common in day-care centers
Diagnosis / Treatment of Giardia lamblia?
Demonstrate in stools
Metronidazole or Nitazoxanide (children) or Tinidazole
- Treat whole family and dog
Life cycle for Trichomonas vaginalis?
No cyst - transmitted via sexual intercourse
Toxic metabolites degenerate vaginal epithelium :(
More basic pH (4, to 5-6)
Symptoms of Trichomonas vaginalis?
Females: persistent vaginitis, itching/burning, whitish discharge
Males: asymptomatic (of course)
Diagnosis / Treatment of Trichomonas vaginalis?
Demonstrate troph in urogential secretion (swab)
Metronidazole (or Tinidazole), NOT during pregnancy
Life cycle of Cryptosporidium parvum?
Fecal/oral ingestion of oocyst
Multiply asexually in epithelium of intestine
Pathogenesis of Cryptosporidium parvum?
Reduces absorptive surface –> WATERY diarrhea
- Really bad in immunocompromised (also affects respiratory system) - AIDS-defining
Self-limiting in the immunocompetent
Bonus parasite! Cyclospora
Symptoms? Get it from where?
- Watery diarrhea
- Guatemalan raspberries
Detect oocysts and treat with Bactrim
Diagnosis and treatment of Cryptosporidium parvum?
Demonstrate the small oocyst in feces
Nitazoxanide; maintain water/salt balance
