Lect 7 Flashcards
Giardia lamblia is found in what animals
beavers, dogs, cats, primates
- zoonosis, cross infectivity between animals and humans
Giardiasis is most common in what patient population
children
Giardiasis is caused by what organism (name both names)
- Giardia lamblia / G. intestinalis
is Giardiasis motile
Flagellate protozoan: very motile
Giardiasis has what two life stages
- Trophozoite
- exists freely in small intestine
- teardrop shape, flagella, 2 nuclei
- feeds on mucus secretions, does not invade tissue
- Cyst
- form passed into environment
- 4 nuclei
- 1 cyst produces 2 trophozoites
what is this organism

Giardiasis
give the life cycle of Giardiasis
- ingestion of cyst (infectious stage)
- Excystation occurs in stomach
- Trophozoites pass into small bowel and divide
- trophozoites in large bowel encyst
- cysts pass into environment
how is Giardiasis passed
drinking water contaminated with feces
when is Giardiasis infection most prevalent
June-October
clinical presentation of Giardiasis that seperates it from other parasites
- watery diarrhea (No blood), abdominal cramps
- vitamin B 12 deficiency
- can be a STI
how is Giardiasis diagnosed
- cysts and/or trophozoites in stool sample
- ELISA dectection of (Giardia specific enzymes 65) GSA 65
protective features against Giardiasis
- human milk - IgA
- phagocytes can kill trophozoites
Amoebiasis is caused by what organism
Emtamoeba histolytica
Describe the two forms of Emtamoeba histolytica
- Trophozoite
- amoeboid with 1 nucleus
- non-flagellated
- pseudopod forming (how it walks)
- invasive and pathogenic
- Cyst
- round in shape
- 4 nuclei
- infectious stage
what is this organism

Emtamoeba histolytica
describe the life cycle of Emtamoeba histolytica
- ingestion of cysts
- excystation in colon
- trophozoites colonize in mucosa of colon
- can encyst and pass in feces OR invade intestinal mucosa
how is E. histolytica contracted
fecal contamination of water and food
Name some high risk populations to getting E. histolytica
- children
- pregnant woman
- long term corticosteroid
- oral-anal sexual practices
clinical presentation
- abd cramps
- bloody stools
- fever
- vomiting
- unintentional weight loss
- Rt upper quadrant pain
E. histolytica
Amoeba hydrolyzes the intestinal lining which results in what condition
- ulcers
- presents as right upper quadrant pain
- death can occur from peritonitis, cardiac failure, exhaustion
List the virulence factors of E. histolytica
- Lectin: adhesion to host cell
- Phospholipases: disrupt host cell membrane
- Amebapore: inserts ion channels into host lipid structure -> lysis of host cell
- Cysteine proteases: degrades mucus, antibody, complement and cellular matrix
how is E. histolytica diagnosed
- trophozoites or cysts in stool sample
- CT and MRI to reveal large cysts (abscesses)
- ELISA to indentify E. histolytica
- PCR
what other condition can E. histolytica create all over the body that is diagnosed with CT/MRI
abscess
Why are E. histolytica infections emerging in backyard pools
cysts are resistant to chlorine
