Parasitology Flashcards
What are the three most prevalent protozoan GI parasites?
Giardia
Cryptosporidium
Entamoeba
How long does diarrhea usually last with a parasitic infection?
Longer than one week
What is the onset for parasitic GI infection like?
Gradual
What are defined as flagellated single celled organisms?
Protozoans
How are protozoans transmitted?
Waterborne
Oral/anal sex
Contaminated food
What stage in the parasitic life cycle are ingested in order to initiate infection?
Cysts or oocysts
How long do symptoms last for giardia?
1-2 weeks or more
What is the mechanism for giardia?
Loss of absorptive surface area
What is the life cycle stage of Giardia that attaches to the gut?
Trophozoites
What do you see in the stool sample of someone with Giardia?
Trophozoites and cysts
What are symptoms for giardia infection?
FOUL smelling diarrhea
Flatulence
Greasy, floating stools
What parasitic infection is often seen where sanitation systems fail?
Cryptosporidium parvum
What is the mechanism for cryptosporidium diarrhea?
Absorption impaired and secretion enhanced
Who is at risk for dying from a crypto infection?
Immunocompromised
What does a crypto infection look like?
Watery, non-bloody stool
Fever sometimes
How do cryptosporidium attach to epithelial cells?
Disrupt epithelial microvilli, enveloping into the host membrane
What do you see in the feces for cryptosporidium?
Acid-fast Oocysts (VERY small)
What relative of crypto is important for outbreaks in the US?
Cyclospora cayetanensis
Where is entamoeba more common to infect?
Tropical/subtropical climates
Does everyone who is infected with entamoeba get ill?
NO! Only 10-20%
What does entamoeba infection look like?
Bloody, mucousal stool
Mild symptms, but can get abscess in liver
How is entamoeba diagnosed?
Cysts in the stool sample
How does amebic hepatitis present?
RUQ pain
Fever
Cachexia
What do you often see entamoeba eating on a H&E stain?
Red blood cells