1What is the most common intestinal parasitic infection in the US?
Giardia lamblia
2What kind of protozoan is Giardia lamblia?
flagellated protozoan parasite
3What does Giardia lamblia do?
colonizes and reproduces in the small intestine, causing giardiasis
4Where and how does the giardia parasite attach?
G. lamblia attaches to the epithelium by a ventral adhesive disc
5How does giardia reproduce?
binary fission
6Describe the spread of giardiasis in the body
giardiasis does not spread via bloodstream or other parts of GI tract;
remains confined to the lumen of the small intestine
7What is the oxygen tolerance of giardia?
anaerobic
8What do giardia trophozoites do?
absorb nutrients from the lumen of the small intestine
9What does Giardia lamblia look like under the microscope?
split and stained looks like a smiley face :)
(tbh looking at the pics, they do not. Not cute at all, they're like bottom feeder-ass lookin' crustypod things at the bottom of the ocean)
10What is the typical lifecycle of Giardia lamblia?
1. noninfective cyst excreted with the feces of infected individual
2. cyst is hardy, providing various degrees of heat, cold, desiccation, and infection from other organisms
3. once ingested, trophozoite emerges to active state of feeding and motility
4. after feeding stage, trophozoite undergoes asexual replication through longitudinal binary fission
5. resulting trophozoites and cysts then pass the digestive system in feces
11What can giardia infect?
[most common: humans, cats, dogs, birds] , cows, beavers, deer, and sheep
12How does giardia infection occur?
through ingestion of dormant cysts in contaminated water, food, or sometimes on objects
13Can giardia cysts survive in cold water? How long?
cysts can survive for weeks to months in cold water
14What are the sources of giardia contaminated water?
contaminated wells and water systems, stagnant water sources (naturally occurring ponds),
storm water storage systems,
mountain streams contaminated by fecal matter.
& even city reservoirs
15How can giardia persist in city reservoirs (after water treatment)?
Giardia cysts are resistant to conventional water treatment methods (like chlorination)
16Is giardia transmission zoonotic?
yes
17What can be a concern knowing giardia is zoonotic?
people camping in the wilderness or swimming in contaminated streams or lakes (especially artificial lakes formed by beavers)
18What is another (fun) name for giardiasis?
beaver fever (haha)
19What are the other transmission routes for giardia (besides water)?
fecal-oral transmission (where there are poor hygiene practices)
20Why can giardiasis occur in day care centers?
increased risk of fecal-oral transmission; those who work with children and family members of those who are infected
21Why are many people 'carriers' of giardia?
not all giardia infections are symptomatic, many people are unknowing carriers of the parasite
22What is the distinguishing characteristic of giardia?
four nuclei and a retracted cytoplasm
23What happens to the trophozoites that pass alongside cysts in feces?
only the cysts are capable of surviving outside the host
24What is the pathology of giardiasis?
colonization of the gut resulting in inflammation and villous atrophy, reducing the gut's absorptive capability
25What is the giardiasis rate of infection in humans?
infection is symptomatic only about 50% of the time
(treating asymptomatic individuals is controversial)
26What are the symptoms of giardia infection?
diarrhea, malaise, excessive gas,
steatorrhea, weight loss, lack of appetite
27What is steatorrhea?
pale, foul smelling, greasy stools
28What does giardiasis infection in healthy individuals look like?
condition is self-limiting
29In what cases can giardia infection become prolonged?
when the patients are immunocompromised or have decreased gastric acid secretion
30How is giardia lamblia diagnosed?
1. microscopy (unreliable)
2. antigen detection
3. direct immunofluorescence assay
31What does an accurate diagnosis of giardia require?
antigen test (or ova and parasite examination of stool);
rather than microscopy, where it can get misdiagnosed
32How is giardia lamblia diagnosed using antigen detection?
stool is tested for giardia antigen using enzyme immunoassay kits
33How is giardia lamblia diagnosed using direct immunofluorescence assay?
stool is tested for parasite itself using immunofluorescent techniques
34Why are multiple stool examinations recommended for all giardia lamblia tests?
the cysts and trophozoites are not shed consistently
35What kind of protozoan is trichomonas vaginalis?
anaerobic, parasitic flagellated protozoan
36What is trichomonas vaginalis a causative agent of?
trichomoniasis
37What is the most common pathogenic protozoan infection of humans in industrialized countries?
trichomonas vaginalis
38How is trichomonas vaginalis transmitted?
sexually transmitted
39What are the infection rates of trichomonas vaginalis between men and women?
infection rates are between men and women are the same
40What gender shows symptoms of trichomas vaginalis?
women;
men are asymptomatic
41Why does transmission of trichomonas vaginalis take place directly?
because the trophozoite does not have a cyst; there is no cyst stage
42How many estimated people have trichomoniasis in the US?
estimated 3.7 million
43What are the symptoms of trichomoniasis?
inflammation of the vagina (vaginitis), greenish-yellow frothy vaginal discharge that smells bad and itching
44What happens to the pH of the vagina when infected with trichomoniasis?
shifts from healthy semi-acidic pH (3.8-4.2) to more basic (5-6) that is conducive to T. vaginalis growth
45What are some other complications of T. vaginalis infection?
1. preterm delivery
2. low infant birth weight and increased mortality
3. predisposing to HIV, AIDS, and cervical cancer
4. pneumonia, bronchitis, and oral lesions
5. subsequent aggressive prostate cancer (in males)
46Where are other areas where T. vaginalis has been reported?
urinary tract, fallopian tubes, and pelvis
47What is the best way to diagnose t. vaginalis?
microscopy; wet mount of a vaginal smear and finding trophozoites at 40X
48What does T. vaginalis under microscopy look like?
trophozoites wiggle around using flagella to swim
49What kind of protozoa is pentatrichomonas hominis?
flagellated protozoa with no cyst stage
50What kind of symbiotic relationship does pentatrichomonas hominis have?
commensal (of the intestinal tract)
51Does pentatrichomonas cause disease?
no
52What is the most common intestinal flagellate in humans (next to g. lamblia and c. mesnili)?
pentatrichomonas hominis
53How is pentatrichomonas hominis acquired?
by swallowing trophozoite; could be fecally contaminated food or water or oral-anal sex
54Where does pentratrichomonas hominis set up residence?
in large intestine
55What species can you find pentatrichomonas hominis?
humans, other primates, and various domestic animals
56How is P. hominis diagnosed?
by finding the trophozoites in a stool specimen
57What kind of protozoan is Chilomastix mesnili?
flagellated protozoan
58What is the infection rate of C. mesnili?
3.5% of population in US
59What organisms are Chilomastix mesnili found?
humans, chimpanzees, orangutans, monkeys, and pigs
60Where does Chilomastix mesnili live?
cecum and colon
61What is the lifecycle of Chilomastix mesnili similar to?
giardia lamblia
62How is chilomastix mesnili acquired?
by ingesting the cysts in fecal contaminated food or water
63Where do C. mesnili cysts become trophozoites? (where do they excyst?)
large intestine
64Is chilomastix mesnili pathogenic or nonpathogenic?
nonpathogenic
65What does C. mesnili often occur with?
other parasite infections (even though it itself is nonpathogenic)
66What is the C. mesnili shape?
lemon shaped
67What is the diagnosis for C. mesnili?
finding cysts or trophozoites in the feces
68How can C. mesnili trophozoite be identified under the microscope?
nucleus at the top of troph
69What form does Dientamoeba fragilis take?
trophozoite form, no cysts!
70How is dientamoeba fragilis acquired?
trophozoite is swallowed in fecal contaminated food or water
71Where does D. fragilis live?
large intestines and passes out with feces
72What does Dientamoeba fragilis feed on?
feeds on intestinal debris
73What kind of symbiotic relationship does dientamoeba fragilis have?
usually commensal but can cause some problems
74What pathological problems can dientamoeba fragilis cause?
diarrhea, abdominal pain, abnormal stools, and abdominal distress
75What is the diagnosis for dientamoeba fragilis?
finding the trophozoite in the stool
76What is unique under the microscope for dientamoeba fragilis?
two nuclei
77What is the only member of the ciliate phylum known to be pathogenic to humans?
Balantidium coli
78What kind of protozoan is Balantidium coli?
parasitic species of ciliate protozoa
79What does Balantidium coli cause?
balantidiasis (disease)
80How is B. coli acquired?
from living in close proximity to pigs;
B. coli cyst swallowed in food or water contaminated with pig feces
81What is the lifecycle of B. coli?
1. Host swallows food or water contaminated with pig feces
2. travels to cecum and colon of humans
3. requires a period of time to adjust to the symbiotic flora of the new host
4. becomes trophozoite
5. once adapted, becomes serious pathogen
6. trophozoites multiple and encyst, due to the dehydration of feces and pass out with feces
82How is B coli zoonotic?
pig is the normal host
83How does B coli affect pig?
asymptomatic
84Why can't B coli readily transmit from one species to another?
requires a period of time to adjust to the symbiotic flora of the new host
85When does B coli infection occur?
when cysts are ingested, usually through contaminated food or water
86Can B coli infect immunocompetent individuals?
uncommon, but if it does, host gets serious disease of gastrointestinal tract
87Who does B coli infection most likely target?
people with malnutrition (due to low stomach acidity), & immunocompromised systems
88What happens in acute disease of B. coli?
explosive diarrhea every 20 minutes, perforation of the colon (leading to life-threatening situations)
89What happens if B coli becomes invasive?
then blood and mucus appears in stools (DYSENTERY)
90Where can balantidiasis be found?
can be found anywhere in the world but is common in the Philippines and those that are in close contact with swine
91How rare is balantidiasis?
rare, occurs in less than 1% of the human population
92Where is balantidiasis most cause problems?
developing countries, where water sources may be contaminated with swine or human feces
93What is the diagnosis of B coli?
finding cysts or trophozoites in the feces
94How can B coli be distinguished under the microscope?
B coli cyst has macronucleus