Giardiasis Flashcards

1
Q

what are the causative agents of giardiasis?

A

Giardia duodenalis
Giardia psittaci

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2
Q

what species get infected with Giardia duodenalis?

A

livestock, companion animals, humans

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3
Q

what species get infected with Giardia psittaci?

A

birds

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4
Q

what type of protozoan is Giardia and where does it infect?

A

flagellate protozoan
infect - upper GI tract

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5
Q

Is giardia monoxenous or heterozenous?

A

monoxenous - direct life cycle

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6
Q

how do trophozoites divide in Giardia spp.?

A

binary fission

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7
Q

what are the key characteristics of Giardia trophozoites?

A

pyriform shape - anterior end broad and rounded
concave, ventral adhesive disc
two nuclei
two median (parabasal) bodies
two axostyles
four pairs of flagella

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8
Q

what is a key characteristic of the Giardia trophozoite that is unique to the genus?

A

median bodies

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9
Q

what are the key characteristics of Giardia cysts?

A

thick walleed cyst
contain 4 nuclei when mature
two trophozoites released from cyst
excystation triggered by gastric acid, pancreatic enzymes, and bile salts

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10
Q

how many trophozoites are released from a giardia cyst?

A

2

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11
Q

what triggers the excystation of giardia cysts?

A

gastric acid, pancreatic enzymes, and bile salts

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12
Q

how many genetic assemblages does Giardia duodenalis have?

A

8

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13
Q

what are the 8 genetic assemblages of Giardia duodenalis?

A

A&B - wide range of domestic and wild animals
C&D - dogs and wild canids
E - hoofed stock
F - cats
G - rodents
H - seals

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14
Q

how is Giardia duodenalis transmitted?

A

direct ingestion of fecal Giardia cysts
indirect ingestion of contaminated water, food, transport hosts, infected prey species, or fomites
re-infection from animal fur when they groom

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15
Q

what is the prepatent period for Giardia duodenalis in dogs and cats?

A

dogs - 4-12 days (mean 8 days)
cats - 5-16 days (mean 10 days)

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16
Q

Is Giardia more prevalent in puppies or kittens?

A

puppies

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17
Q

what are the major virulence factors of Giardia spp.?

A

attachment
circumvention of natural factors of intestinal lumen
antigeni variation
alteration of host innate defenses
anti-inflammatory modifications
survival in stomach acid and external environment

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18
Q

what is the main factor responsible for immune evasion in Giardia?

A

variant-specific surface protein (VSP)

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19
Q

where is variant-specific surface protein found in giardia?

A

covers entire surface of cell

20
Q

where do ingested giardia cysts excyst?

A

duodenum - release two trophozoites

21
Q

where are trophozoites found in dogs and cats?

A

dogs - duodenum to ileum
cats - jejunum to ileum

22
Q

how do giardia trophozoites attach to the brush border of the villus epithelium?

A

ventral adhesive disk
surface molecules
network of contractile proteins

23
Q

what are the proposed mechanisms of disease of giardiasis?

A

apoptosis of enterocytes
loss of epithelial-barrier function
hypersecretion of Cl ions
diffuse microvillus shortening
immune reaction’inhibition of brush-border enzymes and trypsin
interference with bile salt metabolism

24
Q

where is giardiasis most observed?

A

young animals - illness typically more severe and persistent

25
Q

what are the symptoms of giardiasis in dogs and cats?

A

intermittent diarrhea or soft stools, typically light-colored, mucoid, malodorous, may contain fats, unthrifty appearance & weight loss, occasional vomiting

26
Q

where is Giardiasis typically a self limiting ilness?

A

immunocompetent hosts

27
Q

what species is Giardiasis uncommon?

A

horses

28
Q

what are the symptoms of Giardiasis in ruminants?

A

diarrhea (pasty to fluid, mucoid), decreased appetite, loss of weight

29
Q

what is seen in cockatiels and buderigars neonates with avian giardiasis?

A

poor growth and high mortality

30
Q

what type of birds have most clinical cases of Giardiasis?

A

buderigars and cockatiels

31
Q

what species/host is the most implicated in zoonotic transmission of Giardia duodenalis?

A

beavers

32
Q

which has a higher prevalence of Giardia duodenalis - shelter dogs and cats or client-owned animals?

A

shelter dogs and cats

33
Q

what are some clinical suspicious of giardiasis?

A

-previous history of it in environment
-diarrhea unresponsive to antibiotic or coccidiostatic treatment

34
Q

how will a suspected sample of giardiasis be examined under the microscope? (trophozoites and cysts)

A

-direct saline smear for detection of motile trophozoites
-fecal flotation (zinc sulfate floatation) with centrifugation for detection of cysts

35
Q

what some fecal immunoassays that can be done to detect giardiasis?

A

DFA
IFD
ELISA
immunochromatographic assays
antigen detection kits

36
Q

when is fecal PCR most used for giardiasis?

A

identify Giardia duodenalis
not normally used to diagnose

37
Q

what type of diagnostics would be done? If positive for Giardiasis what would be prescribed?

A

zinc sulfate flotation
giardia lateral flow immunoassay
metronidazole prescribed

38
Q

which solution was used in each picture - same sample? what flotation solution should be used to detect giardia?

A
  1. sheather’s sugar solution
  2. zinc sulfate solution
39
Q

does the type of flotation solution matter when detecting giardiasis?

A

YES
use zinc sulfate solution

40
Q

In what species is prevention considered impractical since Giardia is so prevalent in the environment?

A

livestock

41
Q

what are some prevention and control measures for giardiasis?

A

enforce strict sanitation and good management
bird - wire floor cages, raised food and water bowls
post - treatment fecal exam
colostrum management and adequate nutrition

42
Q

what is the feeding stage and infective stage of Giardia?

A

feeding - trophozoite
infective - cyst

43
Q

what medications can be used for Giardia in dogs and cats?

A

Febendazole/metronidazole

44
Q

what medications can be used for Giardia in ruminants?

A

febendazole/albendazole

45
Q

which species with giardia has light-colored, mucoid & malodorous, steatorrhea diarrhea and which has pasty to fluid, mucoid diarrhea?

A

light-colored, mucoid & malodorous, steatorrhea - dogs and cats
pasty to fluid, mucoid - ruminants

46
Q

what effect of Giardia is most responsible for the excess water loss?

A

Excessive secretion of chloride