GI parasites Flashcards
Two types of parasites that cause GI disease
protozoans (single celled) or helminths (worm)
Giardia lamblia reservoir
beaver, cattle, dogs, rodents, sheep etc
What is the common presentation of giardiasis
travelers’ diarrhea
Giardia transmission
spread via cysts: ingestion of cyst-infected water, person-person
At what point of a giardia infection are you symptomatic
when the organism is reproducing in the gut
Clinical presentation of acute symptomatic giardiasis
diarrhea, abdominal cramps, bloating, and flatulence
-sulfuric belching, weight loss
Treatment for giardiasis
metronidazole
Cryptosporidium parasitology
cocccidian
cryptosporidium infectious component
oocyst
Who is most at risk for cryptospiridium
children from 0-4
What is the reservoir for cryptospiridium
calves, lambs, goats, ets
What is the infectious dose of cryptospiridium
as few as 4 oocysts can cause infection
clinical presentation of cryptospiridium infection
severity and duration based on immunocompetency; usually acute, self-limiting diarrhea for 10-14 days
treatment for cryptospiridium
nitazoxanide to shorten duration
cryptospiridium in immunocompromised
severe, chronic, and life-threatening
Pathogenesis of E histolytica infection
E histolytica disrupts protective mucus layer, results in ulcers and dissemination
What is the presentation for an E histolytica infection that has gotten into the portal circulation
hepatic abscess: fever, RUQ pain, rarely diarrhea
Three main tape worms
T saginata (beef) and T solium (pork) and Diphyllobothrium latum (fish)
What kind of infection do tapeworms cause in animals
cysticercosis: cysticerci in striated muscle
Which tape worm is more likely to cause symptoms
T. saginata (beef) because they are larger
Ascaris lumbricoides
most common helminth infection of humans (1/4), need a male and a female in the GI tract to create a severe infection
Ascaris life cycle
ingest the egg > hatches in intestine > larva travels thru mucosa to liver to lung > larva is coughed up and then swallowed > worm is sexually mature in sm intestine
When is ascaris most dangerous
when you have a male and female producing new worms > intestinal blockage
Trichuriasis
found in humid tropical environments and temperate zones
Clinical manifestation of mild trichuria infection
peripheral blood eosinophilia
Clinical manifestation of severe trichuria infection
mucosa is inflamed, edematous and friable; can cause rectal prolapse
Two examples of hookworm
ancylostoma duodenale, necator americanus
How is a hookworm infection acquired?
penetration through skin, carried by blood to heart and lungs, swallowed in sputum, mature in the GI tract
Enterobius vermicularis
pinworm, most common in states
most common presentation of enterobius vermicularis infection
perianal pruritus esp at night in children or institutionalized individuals
