Test 3: Parasitology: Protists Flashcards
T/F: Protozoa/protists are multi-celled eukaryotic microbes
False!
They are single-cell eukaryotic microbes
ex: trichomonas, amoebas
How are protozoans originally classified?
motility
Which group of protozoa does not have motility?
sporozoans
What are some examples of flagellates?
giardia and trich
What are the 3 sporozoa?
toxoplasma, plasmodium, cryptosporidium
What are the 2 flaggellates?
giardia and trich
What is the 1 amoeba?
Entamoeba histolytica
Which flagellate causes veneral disease?
trichomonas vaginalis
Which flagellate causes GI problems?
giardia lambia
What is the most frequent cause of acute symptomatic parasite disease in US and worldwide?
giardia
(regardless of socioeconomic level)
Is Giardia intra or extracellular?
extracellular
Where does Giardia attach?
only attaches and remains localized in small intestine
- able to parasite in wide range of mammals including animals but you won’t get Giardia from a dog
How is Giardia often transmitted?
drinking mountain stream water while camping due to human or wildlife waste
- in the form of infective cysts
- common in outdoor enthusiasts
What kills Giardia?
iodine NOT chlorine
Are Giardia patients symptomatic?
- usually highly symptomatic but sometimes can be asymptomatic
How do the symptoms of Giardia work?
- attachment from this results in inflammation and reduced gut’s absorptive capability so watery diarrhea up to 4 weeks
What is the tx for Giardia?
- metronidazole (flagyl)
What is the prevention of Giardia?
- boiling water ~1 minute to decontaminate drinking water while camping
How is Giardia diagnosed?
- often misdiagnosed but best now to use 3x serial stool antigen test
(antibody would tell us a past exposure to this)
Why is trichonmonas vaginalis named what it is?
- women are symptomatic causing trichomoniasis
but infects both sexes equally
Where does T. vaginalis reside?
only in human urogenital tract
- does NOT form cysts like Giardia does
What is the shape of T. vaginalis?
large organism about size of WBC, only seen in trophozoite form with twitching motility
What does T. vaginalis correlate with?
prematurity, low birth weight, pelvic inflammatory disease, and increases in human immunodeficiency virus transmission
What is the tx for t. vaginalis?
- same as Giardia (metronidizole- flagyl)
What is the dx for t. vaginalis?
- serology test strip
What is the prevention for t. vaginalis?
- safe sex. NO vaccines
T/F: parasites with different developmental stages can require different hosts
True!
What are the distinctive features of cryptosporidium parvum?
- major cause of diarrhea in AIDS pt and immunosuppressive therapies
- majorly seen in HIV epidemic
How is crypto parvum spread?
- is food borne disease and fecal-oral route
- resistant in chlorine-based agents so can spread in swimming pools
What is the pathogenesis of crypto parvum?
- remain located at lumen side of epithelium and disrupt villi
- can be asymptomatic or self limiting watery diarrhea
What is the tx for crypto parvum?
- usually just rehydrate and electrolyte replacement unless it is more severe take metronidazole
What is the dx for crypto parvum?
- acid-fast oocytes in stool via microscopy
- serology tests
What is prevention for crypto parvum?
- water tx and personal hygiene
What are the distinctive features of toxoplasma gondii?
- infect 25-50% where cats are pets due to sexual reproduction of parasite in cat because it is definitive host (most mature form of parasite lives here)
- change behavior of rats and mice making them less scared of cats and zombie ants!
- can also propagate by asexual reproduction independently in a complete life cycle in carnivorous intermediate hosts
How is toxo gonadii spread?
- human infection occurs by ingestion of oocysts shed by cats
- can also involve ingestion of tissue cysts
- congenital transmission
What is the pathogenesis of toxo gonadii?
- ingested oocysts or cysts invade intestinal wall
- **macrophages ingest parasite, then undergo intracellular replication, transport throughout body **
- congenital transmission
What is the dx for toxo gonadii?
- serological tests for IgM antibody
- stool on Omar test
What is the tx for toxo gonadii?
- pyrimethamine and sulfadiazine because they block folic acid synthesis
What is the prevent for toxo gonadii?
- avoid undercooked meat
- pregnant women avoid changing cat litter
- cats kept inside
What’s the agent of malaria?
plasmodia
What are the distinctive features of plasmodium?
- most deadly human parasitic disease, malaria
- 4 species ( know falciparum) that can be rapidly fatal
- in sub-saharan africa
- exactly 2 hosts= human and mosquito (definitive host)
What is the pathogenesis of plasmodium?
- mosquito bite- travel to liver- infect hepatocytes- multiply without causing symptoms by binary fission- released into bloodstream- enter and multiply synchronously in RBCs causing sweats and fever
What is the deadly form of plasmodium?
plasmodium falciparum
- others are more benign and have time to find tx
What is the dx for plasmodium?
- blood films/ smears on glass for rings in RBC or banana-shaped gametocyte forms
What is the tx for plasmodium?
- quinolones, chloroquine
- herbal combos of drugs containing artemisinin
What is the prevention for plasmodium?
- travelers can use prophylactic tx with cholorquine
