Parasitology > Protozoa > Flashcards

Protozoa Flashcards

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1
Q

What protozoa causes coccidiosis in chickens and other hosts?

A

Eimeria spp.

- reason why commercial chickens are on a coccidiostatic

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2
Q

What 4 protozoans cause reproductive failure in various hosts?

A
  • Toxoplasma gondii
  • Tritrichomonas foetus
  • Neospora caninum
  • Sarcocystis cruzi
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3
Q

What 2 protozoans cause CNS disease?

A
  • Toxoplasma gondii

- Sarcocystis neurona

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4
Q

What 7 protozoans have zoonotic potential?

A
  • Babesia
  • Balantidium
  • Cryptosporidium
  • Leishmania
  • Giardia duodenalis
  • Toxoplasma gondii
  • Trypanosoma
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5
Q

General protozoan characteristics

A
  • unicellular/multicellular stages
  • eukaryotes with organelles
  • aqueous/moist environment to feed and reproduce (many have a cyst stage)
  • life cycles vary
  • reproduction includes sexual and asexual stages
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6
Q

Identification is based on morphology of

A
  • unique organelles, nucleus number/shape/size
  • tissue cyst
  • motile stages
  • stages in RBC
  • oocyst morphology
  • gross lesions
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7
Q

What 3 protozoans have blood stages?

A
  • Plasmodium
  • Leucocytozoon
  • Babesia
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8
Q

What is the causative agent of blackhead in turkeys?

A

Histomonas meleagridis

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9
Q

Giardia has _________ distribution

A

Worldwide geographical distribution

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10
Q

What is the most common flagellate of birds/mammals/reptiles/amphibians?

A

Giardia

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11
Q

Does Giardia have a direct or indirect life cycle?

A

Direct

- stages: trophozoite and fecal cyst

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12
Q

What type of reproduction does Giardia undergo?

A

Asexual

- binary fission

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13
Q

Infective stage of Giardia

A

Cyst stage in feces that can survive for months

- gets passed on in environment thru infected water/food or contaminated predator/prey

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14
Q

Routes of infection for Giardia

A
  • fecal oral

- carnivorism

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15
Q

Is Giardia intracellular?

A

No

- just lays on intestinal villi

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16
Q

Giardia sites of infection

A

Small intestine
- trophozoites in small intestine (rarely in large intestine)

Trophozoites encyst in large intestine –> cyst stage excreted in feces

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17
Q

Animals infected with Giardia are __________

A

Intermittent shedders

- need 3 consecutive samples across 3 days to detect

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18
Q

Trophozoites

A
  • size: 4-10 micrometers
  • 2 nuclei
  • flagellated
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19
Q

Giardia trophozoite diagnostic stages/techniques

A

Need a fresh sample from diarrhea!

  • direct smear: look for motile trophozoites
  • Lugol’s iodine stain
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20
Q

Fecal cysts

A
  • size: 4-10 micrometers

- 4 nuclei, no flagella

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21
Q

Giardia fecal cyst diagnostic techniques

A 
Flotation
- zinc sulfate or Sheather's solution (collapses cyst)
- antigen test (snap test)
- direct FA test
PCR
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22
Q

Giardia pathology dog/cat

A
  • diarrhea, often intermittent
  • affects young animals
  • malabsorption, weight loss
  • mucus, fluid in SI
  • associated with concurrent infections
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23
Q

Giardia pathology ruminants

A

Primarily assemblage E!!

  • high prevalence worldwide
  • young most susceptible to acute infections
  • chronic diarrhea, high morbidity
  • adults chronically infected, reinfected
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24
Q

Giardia in humans is associated with

A
  • Irritable bowel syndrome
  • Chronic wasting
  • Failure to thrive syndrome
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25
G. duodenalis assemblages _____ infect humans, livestock, dogs, cats, wildlife
A/B
26
Giardia cysts are ______ infective
Immediately
27
Epidemiological factors
- water and food borne, mechanical/transport hosts - population density, poor hygiene = potential for fecal contamination - age/passive immunity - colostrum - host specificity/reservoir hosts
28
Who is the reservior host for Histomonas meleagridis?
Chickens | - not pathogenic for chickens, but are a source of infection for turkeys
29
Histomonas meleagridis definitive host
Turkeys, chickens, pheasants, guinea fowl
30
H. meleagridis primary sites of infection
Liver and ceca
31
H. meleagridis life cycle
Direct - Heterakis gallinarum (cecal nematode) eggs are required as a transport host - Heterakis eggs are long lived in the environment, can survive for months - H. gallinarum eggs are transported into bird host
32
H. meleagridis infective stage
Motile trophozoites | - found in H. gallinarum eggs
33
H. meleagridis route of infection
Ingestion of infected embryonated H. gallinarum eggs
34
H. meleagridis alternate route of infection
Paratenic host | - bird to bird transmission via cloacal drinking
35
Once H. gallinarum egg is ingested ...
Egg hatches and H. meleagridis is released into intestine --> systemic via blood vessels --> liver, ceca (where trophozoites undergo binary fission) In the ceca: H. meleagridis infects Heterakis gallinarum female and is incorporated into nematode eggs
36
Blackhead
Lethargy, stilted gate, cyanosis occurs 7-12 days post infection - mortality 17 days post infection
37
H. meleagridis lesions
Liver: circular depressions of necrosis, enlarged Ceca: cecal core, ulceration --> perforation --> peritonitis
38
H. meleagridis is more pathogenic with _______
Concurrent infections - C. perfringens - E. coli - Eimeria tenella
39
H. meleagridis diagnosis
- clinical signs - cultivation is difficult - pathology/histology: lesions in liver/ceca
40
What are the 3 rule outs for H. meleagridis?
- Eimeria tenella - Salmonella - E. coli
41
H. meleagridis treatment
- no approved drugs - control of Heterakis gallinarum - avoid co-habitation of bird species, problem with free range birds
42
General trichomonad characteristics
Trophozoite - 3-5 anterior flagella - undulating membrane (motility) - axostyle - single nucleus - no cyst stage - 4-30 micrometers * *do not have a cyst stage!**
43
Most trichomonad species are not _______
Pathogenic | - intestinal/high numbers
44
Tritrichomonas foetus
Infect cattle worldwide - endemic in free-ranging herds - causes trichomonad abortions, trichomonosis
45
T. foetus location in host
- female: repro tract (vagina/uterus) - male: penis sheath, seminal vesicles, testicles - fetus: fluids from abortion, stomach
46
Bulls are considered to be carriers ______ once a diagnosis is made
For life - young bulls: less likely to transmit - bulls over 3 yrs are greater risk due to higher surface area
47
Tritrichomonas life cycle
Flagellated trophozoites introduced during sex --> trophozoites reproduce asexually in repro tract (binary fission) --> mature trophozoites in 14-20 days post-infection - direct life cycle * *no cyst stage**
48
Tritrichomonas foetus clinical signs
Males: asymptomatic Females: infertility, vaginitis, cervicitis, chronic vaginal inflammation Fetus: aborted within 16 weeks
49
Tritrichomonas diagnostic stage
Trophozoite - motile, flagellated, undulating membrane, 3 anterior flagella - presence on wet mounts - sample from repro tract on saline - culture: in pouch TF system - combine: culture, PCR, wet mounts
50
Tritrichomonas - treatment/control
No approved drugs Control - test before introduction of bull/cows - AI - test bulls annually --> neg bull requires 6 consecutive negs or 3 negs over several weeks - cull positive cows and vaccinate females
51
Tritrichomonas blagburni (foetus)
Feline trichomoniasis - intestinal trichomoniasis in cats (large intestine) - blagburni and foetus are genetically distinct
52
Tritrichomonas blagburni transmission
Trophozoites transmitted via fecal/oral route - binary fission in large intestine - young, pure-bred show cats, and group housed cats at greater risk
53
T. blagburni and T. foetus cross transmission studies
- cattle isolate in cats = low infection, less pathology | - cat isolate in cattle = less pathology
54
T. blagburni pathogenesis
Large bowel inflammation - "large bowel disease" - chronic diarrhea (relapses) - hemorrhagic, muccoid stool
55
T. blagburni diagnosis
History of diarrhea - -> FIV, corona virus, FeLV, cryptosporidium, giardia - motile trichomonads in feces - culture (in pouch), PCR
56
What are 2 rule outs for Tritrichomonas blagburni?
- giardia | - pentatrichomonas hominis
57
Feline tritrichomoniasis treatment/control
Unsuccessful treatments | Control: isolation of cats, repeat testing
58
T. blagburni transmission
Cat to cat | - grooming, litter boxes, feed, water
59
Tritrichomonas foetus other hosts
``` Swine - site: stomach, colon, nose - no pathology Dogs - site: large intestine - pathology: diarrhea Humans - one case ```
60
Trichomonas gallinae
Infects wide range of avians | - located in upper GIT, extraintestinal
61
T. gallinae trophozoite
- 4 anterior flagella - undulating membrane, axostyle - single nucleus - no cyst stage
62
Trichomonas gallinae life cycle
Trophozoites introduced orally --> divide via binary fission --> passed to next host orally
63
T. gallinae routes of infection
- mother to offspring via regurgitation - water/feed contamination - predator/prey - courtship - pigeons may be reservoir hosts
64
Trichomonas gallinae pathology
"Canker", roup, frounce, trichomoniasis - upper GIT --> invade mucosal surface - caseous lesions - secondary infection - strain differences
65
T. gallinae diagnosis
- gross lesion - direct smear - histopathology
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