Protozoa Flashcards

describe what protozoa are, including what animal kingdom it belongs to

one-celled, eukaryotic microorganisms belonging to the animal kingdom “protista”

protozoa may be found in the ______ as intestinal protozoa or in the blood as ____________

feces; hemoprotozoa

how are intestinal protozoa classified?

by their type of movement within the host

what are the 3 ways intestinal protozoa can move?

by pseudopodia, by flagella, or by a gliding movement

what are pseudopodia?

“false feet”

what 2 forms may intestinal protozoa be encountered in the feces of infected animals?

the trophozoite form or the cyst form

what objective lens should intestinal protozoa be viewed using?

10X (some require 40X)

describe what trophozoites are

the motile stage in the protozoan life cycle that are capable of feeding & movement

why are trophozoites difficult to recognize in fecal flotation solutions?

because they lack rigid cell walls, they collapse

which fecal testing procedure is used to observe live trophozoites in feces?

a thin direct fecal using saline

how are the trophozoites of various protozoan recognized?

by their movement patterns

how can trophozoites be stained or preserved?

using Giemsa, Wright’s, or Diff-Quik stain on fecal smears

describe what cysts are

the dormant stage in the protozoan life cycle that are incapable of movement

cysts can be stained / preserved with…

Lugol’s iodine

cysts are observed in stained specimens from _______ or ______

tissues or feces

describe the durability of cysts passed in the feces

they have a protective wall that enables them to survive in the outside environment for a period of time ranging from days to a year

how are blood protozoa identified?

on stained blood smears using 100X (oil immersion)

protozoa seen between RBCs are called…

extracellular blood parasites

protozoa seen within or on the RBCs are called…

intracellular blood parasites

what should blood donors be screened for prior to donating blood for transfusions?

infectious diseases

an amoeba that causes amoebic dysentery

Entamoeba histolytica

list the 2 primary hosts of Entamoeba histolytica

humans & nonhuman primates

is Entamoeba histolytica of zoonotic concern?

yes!!

what does Entamoeba histolytica cause?

colitis & liver abscesses

where is Entamoeba histolytica most common? how is it transmitted?

in countries that have poor sanitary conditions; transmitted by fecal-oral contact through contaminated food or water sources

how is Entamoeba histolytica identified & in what form(s)?

direct fecal or fecal float on 40X; trophozoite or cyst forms

how does Trichomonas spp. move?

by flagella & undulating membranes

where does Trichomonas spp. live?

in warm, moist, anaerobic environments such as the oral cavity, GI tract, and genital tract

how is Trichonomas spp. transmitted?

directly from host to host

T/F: all Trichonomas spp. are pathogenic

false

how is Trichonomas spp. identified?

direct fecal using saline; view on 40X; look for movement pattern - jerky, spinning motion

what is unique about Trichonomas spp?

it has no cyst form

which protozoa belongs to a group of primitive protozoans?

Trichonomas spp.

how can Trichonomas spp. proliferate?

due to the increased fluid medium associated with diarrhea

when see in dogs & cats, it is important to rule out other causes of _________

diarrhea

a venereally transmitted parasite of the reproductive tract in cattle

Tritrichomonas foetus

what can Tritrichomonas foetus in cattle cause?

abortion & infertility

how do you treat Tritrichomonas foetus in cows?

self-limiting; sexual rest for 3 months is the only treatment necessary to eliminate the parasite from the female

how do you treat Tritrichomonas foetus in bulls?

bulls are permantely infected; slaughter is necessary to eliminate them from spreading the infection

how has Tritrichomonas foetus disease been largely been eradicated?

by the use of artificial insemination (AI) using uninfected bulls

Tritrichomonas foetus can cause ______ in domestic cats

colitis

T/F: some cats may serve as carriers of Tritrichomonas foetus & show no clinical signs

true

what do cats affected with Tritrichomonas foetus typically present with?

chronic, intermittent large-bowel diarrhea (which may contain blood or mucus) that is copious & foul-smelling

where is there a high prevalence of Tritrichomonas foetus in cats?

animal shelters, catteries, pet shops, other multi-cat environments

how is Tritrichomonas foetus transmitted in cats?

via the fecal-oral route, particularly in cats that share litter boxes and / or groom themselves

how is Tritrichomonas foetus identified in cats?

by observation of live organisms in a direct fecal (using saline), fecal culture, or PCR testing

how is Tritrichomonas foetus treated in cats?

infection will resolve spontaneously, but can take months to years

a protozoan that affects the oral cavity of pigeons, doves, poultry, and birds of prey

Trichomonas gallinae

Trichomonas gallinae is responsible for the disease known by falconers as _______

frounce

frounce has a fatality rate of __-__%

80-90%

describe the disease process of frounce

it causes cheesy, necrotic lesions (“canker”) in the mouth, esophagus, and crops of pigeon swabs

the most common flagellated intestinal protozoan infecting mammals (including people) & birds

Giardia spp.

what does Giardia spp. cause in the host?

chronic diarrhea

what is the life cycle of Giardia spp?

direct

how is Giardia spp. transmitted?

via fecal-oral route by ingestion of infective cysts in contaminated food & water, fomites, or through self-grooming

what happens once Giardia spp. cysts are ingested?

the cysts open (excyst) and the trophozoites attach to the intestinal mucosa

describe Giardiasis

the trophozoite motile form attaches to the epithelial cells in the upper third of the small intestine of its host; the trophozoites multiply rapidly & form a cyst that is excreted in the host animal’s feces

describe a Giardia spp. cyst

the cyst has a tough, protective wall around it that allows the protozoa to survive in the environment

how is Giardia spp. identified?

by observing motile, flagellated teardrop-shaped trophozoites in a direct fecal using saline; view on 40X

describe the movement pattern & appearance of Giardia spp.

exhibit a “falling leaf” movement pattern & a “monkey-faced” appearance when stained

which solution is recommended for recovering the cyst stage of Giardia spp?

zinc sulfate

because Giardia spp. cysts are shed in the feces intermittently, what should be done?

at least 3 separate NPS fecal samples should be examined in-house over the course of a week before ruling out the parasite as the cause of diarrhea

T/F: Giardia spp. infections are one of the easiest to identify

false; it is one of the most commonly misidentified internal parasite

list 3 reasons Giardia spp. infections are difficult to identify

1. misidentification of Giardia spp. cysts

2. cysts are shed intermittently & readily deteriorate in fecal flotation solutions

3. trophozoites are only found in very fresh diarrhea

control of Giardia spp. in birds

good sanitation & preventing access to contaminated food & water sources

what disease process is commonly associated with Giardia spp. in cockatiels?

an allergic skin condition resulting in feather picking

pet birds infected with Giardia spp. usually have what kind of diarrhea?

voluminous, chunky, “pea-soup”

T/F: heavy Giardia spp. infections in birds can be fatal

true

the two genera commonly called “coccidia”

Eimeria spp. & Cystoisospora spp.

describe what coccidia is

intracellular parasites of the intestinal epithelium

the disease ___________ refers to infections caused by either Eimeria spp. or Cystoisospora spp.

coccidiosis

what is coccidiosis associated with?

stress, overcrowding, improper ventilation, poor sanitation

coccidiosis caused by Eimeria spp. affects…

ruminants, poultry, rabbits, pigs, horses, and rodents

coccidiosis caused by Cystoisospora affects…

dogs, cats, and pigs