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Parasitology > Protozoans > Flashcards

Protozoans Flashcards

1
Q

Name 4 different types of organelles of locomotion seen in Protozoans

A
  1. Flagella
  2. Cilia
  3. Pseudopods
  4. Undulating ridges, subpelliccular microtubules
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2
Q

Name 5 different modes of Protozoan reproduction

A 
Most reproduction is asexual 
1. Binary fission 
2. Multiple fission, schizogony 
3 budding 
4. Conjugation
  1. Gametogony = sexual
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3
Q

Autotrophic

A

Ability to produce its own nutrients

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4
Q

Heterotrophic

A

Organism that must obtain its food

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5
Q

Holozoic

A

A heterotroph that ingests via mouth

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6
Q

Saprozoic

A

A heterotroph that absorbs nutrients through cell membrane

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7
Q

What is the classification of Protozoans

A 
Kingdom Protista 
Subkingdom Protozoa 
Phylum : Sarcomastigophora 
                Apicoomplexa 
                Ciliophora 
                Microspora
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8
Q

What Phylum under the Kingdom Protista does Giardia belong to?

A

Phylum Sarcomastigophora

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9
Q

In what two forms does Giardia exist?

A
  1. Trophozoite

2. Cyst

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10
Q

Discuss the morphology of trophozoites

A

Adhesive disk, 2 nuclei, 8 flagella

Pear shaped , flat dorsoventrally

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12
Q

Which giardia form is infective

A

Cyst

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13
Q

Discuss the morphology of a Giardia cyst

A

Oval, thick walled, refractile wall

Nuclei is less prominent than in trophozoites and occupy one end of the cyst

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15
Q

Describe the two forms of giardia.

A

Cyst = infective, 4 nuclei, oval and thick wall; found in formed feces

Trophozoite = motile, bilateral symmetry, flattened dorsoventrally, pear shaped,8 flagella, 2 nuclei, found in diarrhea

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16
Q

What kind of lifecycle does Giardia have?

A

Direct,no IH

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17
Q

Giardia lifecycle

A
  1. Cyst stage ingested - can survive in food/water for several months
  2. Excystation in duodenum
    - attach via adhesive disks to microvilli of epi cells in SI
  3. Trophozoites replicate via longitudinal binary fission
  4. Encyst meant in lower gi tract
    5 infective cysts passed in feces

Pre-patent period = 1 wk

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18
Q

What are the clinical signs of Giardiasis?

A

Chronic infections
Intermittent diarrhea - loose and mucous, no blood
Majority asymptomatic

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19
Q

How can you dx giardia?

A

FF - to find cyst
Direct smear- find motile trophozoite
Elisa - if this is positive then we should be sent cysts on a fecal float

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20
Q

What preparation technique in a fecal will keep nuclei intact

A

Using zinc sulfate with iodine dye

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21
Q

What Phylum do Trichomonads belong to?

A

Phylum Sarcomastigophora

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22
Q

Trichomonads

How do they move? 2 ways

What is their supportive structure?

How do they reproduce?

What is the name of the form taken during extreme conditions?

A

Flagella, undulating membrane

Axostyle - which is similar to ventral groove in giardia

Longitudinal binary fission

Pseudocysts

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23
Q

What causes Bovine Genital Trichomonosis and Veneral Disease?

A

Tritrichomonas foetus - sexually transmitted

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24
Q

How does Bovine Trichomonosis affect birth in cattle?

A

Embryonic death and abortion

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25
Q

How do you dx trichomoniasis?

A

Preputial wash - sample from fornix and glans penis of bull

Or uterine/vaginal smears, placental fluid

PCR tells you species, differentiate infections from non infectious

Culture organism

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26
Q

What is large bowel disease?

A

feline trichomoniasis causes by

Tritrichomonas blagburni

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27
Q

What clinical signs are seen with feline trichomoniasis?

A

Chronic diarrhea
Flatulent
Irritated anus
Fecal incontinence

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28
Q

How is Feline Trichomoniasiis transmitted

A

Transmission is unknown

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29
Q

What are some unique features of feline trichomoniasis?

A

Chronic diarrhea
Ave 9months age of onset
Diarrhea may relapse
Spontaneous resolution

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30
Q

What protozoan is a member of the Family Trypanosomaidae

A

Trypanosome cruzi

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31
Q

What is a parasite of all classes of vertebrates, majority transmitted by blood feeding invertebrates, but dont cause disease

A

Trypanosomes - Protozoans

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32
Q

What are the two general shapes of trypanosomes?

A

Elongated cell bodies with single flagella OR rounded cell body, short flagella

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33
Q

Trypomastigote

A

Stages of trypanosome

  • elongated cell body
  • single flagellum
  • blood stage
  • kinetoplast at cell posterior
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34
Q

Promastigote

A

Stages of trypanosome

  • elongated cell body
  • single flagellum
  • mainly insect vector
  • kinetoplast at cell anterior
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35
Q

Epimastigote

A

Stages of trypanosome

  • elongated cell body
  • single flagellum
  • some species
  • kinetoplast between nucleus and anterior
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36
Q

Amastigote

A

Stages of trypanosome

  • rounded cell body
  • short flagellum if present at all
  • some species
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37
Q

What is the vector of American Trypanosomiasis/ Chagas Dz – Trypanosoma cruzi

A

Resuviid bug

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38
Q

What two stages of trypanosomes are seen in Trypanosoma cruzi?

A

Trypomastigote in circulating blood

And

Amastigote pseudocyts, in neural cells of muscles

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39
Q

What is the infective state of Trypanosoma cruzi?

A

Metacyclic trypomastigote

40
Q

what is the life cycle of Trypanosoma cruzi?

A

IH = Reduviid bug DH = dogs, humans
Reservoir hosts = cats, opossums, armadillos, raccoons, rads

  1. IH Redivide bug bites DH, Metacyclic trypomastigotes = Infective stage passed in feces and enters wound
  2. Trypomastigotes enter circulation and then cells of spleen, lymphs, muscles, liver
  3. Transform into amastigote stage - replicate via binary fission forming pseudocysts
  4. Cells rapture and trypomastigotes released into circulation or can reinfect the cell
  5. Trypomastigotes get picked up IH and become epimastigotes via binary fission
  6. Metacyclic tryptomastigotes apear in rectum and passed via feces
41
Q

What animal is affected by American Trypanosomiasis?

A

Dogs via Trypanosome cruzi

Mainly sporting dogs, working dogs

42
Q

What are the features of American Trypanosomiasis Acute Dz

A

Trypanosoma cruzi

Trypomastigotes in circulation

  • myocarditis
  • pale mm
  • lethargy
  • hepatomegaly
  • splenomegaly
43
Q

What are the features of American Trypanosomiasis Chronic Dz

A

Trypanosoma cruzi

No circulating trypomastigotes

  • dilated heart
  • arrrhythmia
  • lethargy
  • resp difficulties
  • anemia
44
Q

How can Trypanosoma cruzi be dx?

A

Serological testing
Blood smear
Xenodiagnosis

45
Q

What are the characteristics of Phylum Apicomplexa?

A

Distinct nucleus
Movement = subpellicular tubules
Apioccal complex

46
Q

Name 2 orders under Phylum Apicomplexa

A

Order Eucoccidiia

Order Piroplasmida

47
Q

Name the two Genera under Order Eucoccidiia that we studied

A

Genera Eimeria
Genera Cystoisospora

Both of these are considered coccidia which are part of Sporozoea due to producing a resistant spore-like cyst stage

48
Q

Name 4 characteristics of Cystoisospora and Eimeria

A
  1. Stenoxenous = host specificity, species specific
  2. Site specificity = depending on species but usually
    SI or LI, rarely liver or kidney
  3. Monoxenous = parasitism of one host, DH
    -Direct life cycle, no IH
49
Q

What species are affected by Cytoisospora?

A

Dogs, cats
Pigs
Humans - severe in AIDS patients

50
Q

What species are affected by Eimeria?

A

Bird, cattle, small ruminants
Horses, rabbits rodents
Pigs

51
Q

What type of reproduction do Eimeria and Cystoisospora have?

A

Asexual = sporogony, schizogony (merogony) = multiple fission

Sexual = gametogony

52
Q

What is the infective stage of Cystoisospora Eimeria

A

Coccidian

Both have sporuated oocyts = infective stage

53
Q

Describe the life cycle of Cystoisospora and Eimeria

A
  1. Sporolated oocyst = sporocyst ingested by host
  2. Sporozoites excyst from sporocyst
  3. Attach epithelial cells as trophozoite
  4. Schizogony occurs within schizont = asexual reproduction
  5. Merozoites form gametocytes
  6. Gametogogny between macrogametocyte (female) and microgametocytes (male)
  7. Zygote to Oocyst, oocytes released in feces
  8. Oocytes undergoes sporogony = asexual reproduction in the environment
  9. Sporocyst formed in environment = infective stage
54
Q

What is the outcome of Sporogony for Cystoisospora

A

Within one oocyst 2 sporocysts produced

Inside each sporocyst = 4 sporozoites

55
Q

What is the outcome of Sporogony for Eimeria

A

After sporogony, within one oocyst = 4 sporocysts

Inside each sporocyst = 2 sporozoites

56
Q

How is coccidia trasmitted?

A

Sporulated oocyst from contaminated food, water, bedding, or litter

57
Q

What are the two common causes of calf coccidiosis?

What are three characteristics of this dz?

A

Eimeria bovis and Eimeria zuernii

Resistant oocysts
Development in terminal ileum and colon
Intracellullar

58
Q

Which calf coccidiosis is easier to dx? And why?

What reproductive stage causes most damage?
What is the major damage?

A

Eimeria bovis

  • oocytes present when dz begins
  • Gametogony causes majority of damage.
  • causes mucosal damage
59
Q

What calf coccidiosis is more severe?

What reproductive phase causes most damage?

How many phases does this dz have?

A

Eimeria zuernii

  • schizogony produces most damage
  • characterized by bloody diarrhea
  • acute phase = death common and mucosa destroyed
  • chronic phase blood loss abates diarrhea persists
60
Q

Which coccidia studied is not zoonotic

What are its clinical signs

A

Cystoisospora

Occasional diarrhea, death
Enteritis,colitis, weight loss, dehydration

61
Q

What are common paratinic hosts of Cystoisospora

A

Mice, rats, hamsters, other vertebrate

62
Q

Which 3 parasites belong to Phylum Apicomplexa, and are considered related to Coccidians?

A

Cryptosporidium
Toxoplasma gondii
Sarcocystis

63
Q

What is the habitat of Cryptosporidium?

A

Intestines - microvillus border, intracelluar

64
Q

What is the infective stage of Cryptosporidium?

A

Sporulated oocyst - containing 4 sporozoites

Thick resistant cyst wall

65
Q

How is Cryptosporidium transmitted?

A
  • direct contact with infective oocyst
  • mucosal scrapings or tissue homogenates
  • contamination - food or equipment
  • water

**low infective doses, oocysts are small have significant resistance

66
Q

What water processing methods are effective against Cryptosporidium?

A 
Reverse osmosis 
Distilled 
Filtered using filter 
Steaming hot tea/coffee 
Pasteurized 
Canned/bottled soda
67
Q

What parasite is characterized by yellow, profuse watery diarrhea in young calves?

A

Cryptosporidiosis

68
Q

Lifecycle of Cryptosporidi

A

Exogenous
1. Sporulated oocyst (sporocyst) with 4 sporozoites
released from infected host

Endogenous

  1. Sporocyst ingested
  2. Sporozoite - trophozoite – undergoes schizogony = asexual reproduction
  3. Schizont release merozoites that can either reinfect host or differentiate to macro + microgametocytes
  4. Gametogony occuse = sexual reproduction
  5. Zygote formed, then oocyst with 4 sporozoites
  6. Oocyst can either remain in host or be released as sporocyst

Aka sporogony occurs in the host

69
Q

Which member of Phylum Apicomplexa has a Felidae definitive host and IH encompassing virtually all mammals including humans

A

Toxoplasmosis

70
Q

What are the two forms of transmission for Toxoplasmosis

A

Acquired – via infective oocyst in feces or undercooked/raw food

Congenital- transplacental transmission

71
Q

What are the two stages of toxoplasma gondi?
Where are they found?
What are their grouped/surrounded phases called?

A

Tachyzoites = rapidly dividing, in liver, lungs, spleen, lymph nodes
-pseudocyst = group of tachyzoites, NOT surrouded by cyst wall

Bradyzoites = slowly dividing, found in brain, heart, skeletal muscle, eye
-cyst = group of bradyzoites surrounded by resistant cyst wall

72
Q

what are the 3 ways the DH can acquire toxoplasma gondii

A

DH = Felids

  1. Sporulated oocyst from feces of other cats
  2. Tachyzoite - congenital - through placenta
  3. Bradyzoite - encysted in IH
73
Q

What is the only way an IH can acquire Toxoplasma gondii

A

IH = mosts mammals

Infected by sporulated oocyst

74
Q

Discuss the lifecycle of Toxoplasma gondii

A
  1. Cat ingests either sporulated oocyst, or ingests IH infected with bradyzoite, or congenital via placenta
  2. Schizogonoy and gametogony occurs in intestines
  3. Oocysts in feces
75
Q

What stage of Toxoplasma gondii crosses placenta and affects fetus?

A

Tachyzoite

76
Q

Discuss the life cycle of Toxoplasma gondii in the IH

A
  1. IH ingested sporulated oocyst
  2. Tachyzoites develop in any cell except RBC
  3. Immunity develops
  4. Bradyzoites develop cysts in host tissue
    - cycle may reinitiate after decline of immunity cycle
77
Q

How to dx Toxoplasma gondii?

A

FF

Serological examination
Histology
PCR

78
Q

When does a cat shed Toxoplasma gondii?

A

No confirmed oocyst shedding in clinically ill cats – only shed once

Relapse can happen but often with immunosuppressed animals or concurrent infection with Isospora felis

79
Q

Who are the carriers of Bovine Genetil Trichomonosis?

A

Bulls are chronic carriers and a symptomatic

80
Q

How does the DH of Sarcocystis become infected? The IH?

A

DH = carnivores/predator ingests sarcocyst = tissue cysts in IH

IH: herbivores/prey infected when grazing or ingest contaminated food/water with sporocyst

81
Q

What does a Sarcocystis sporocyst look like?

A

4 long projections with residual body at the base

82
Q

Describe the life cycle of Sarcocystis

A
  1. DH ingests prey tissue w/ sarcocyst
  2. Merozoites released
  3. gametogony in DH intestine
  4. Sporogony
  5. Sporocysts released in feces
  6. Sporocyst ingested by IH via grazing or contaminated food/water
  7. Schizogony = Schizonts forms in endothelial cells of BV of brain, liver, kidney
  8. Sarcocyst in IH skeletal and cardiac muscle await DH ingestion
83
Q

What causes Dalmeny Disease in cattle?

A

Sarcocystis cruzi

84
Q

What animal is a true intermediate host for Sarcocystis bertrami, S. Fayeri, S. Equicanis

A

Horse

85
Q

What is the outcome of infection of Sarcocystis neurona to the horse?

A

In this case the horse is an aberrant host

  • Equine Protozoal Myeloencephalitis
    Causes CNS dz as schizonts develop in neural cells and destroy them
    Sarcocyst do not deveop
86
Q

How to dx Sarcosporidiosis

A

FF
Schizont in IH, sarcocysts via biopsy/necropsy
Western blot
PCR

87
Q

What parasite is characterized by piroplasm invasive stages?

A

Cytauxzoon felis

Phylum Apicomplexa
Order Piroplasmida

88
Q

Cytauzxoon felis

DH

IH/vector

Reservoir host

A

DH: domestic cats

IH/vector = Dermacentor variabilis and Amblyomma americanum = ticks

Reservoir host = N. American bobcat

89
Q

Discuss lifecycle of Cytauxzoon felis

A
  1. Tick feeds on infected host = ingests piroplasm in erythrocyte
  2. Piroplasm travel to salivary gland of tick = asexual reproduction
  3. Infected tick feeds on DH - cats
  4. In cat – Piroplasm to schizont = schizogony occurs in macrophages
  5. In cat - merozoites released when macrophages rupture.
  6. Merozoite released when macrophage ruptures
  7. Enter erythrocyte and develop into piroplasms.
90
Q

Transstadial trasmission

A

Occurs in ticks that carry Cytauxzoon felis = pick up pathogen at a young stage and carries as it molts into adult

91
Q

What phase of Cytauxzoon felis is most destructive?

A

Schizogenous phase - macrophages infected w/ schizonts block blood vessels, multi- organ failure

92
Q

DX Cytauxzoon felis

A

Blood smears
PCR
Biopsy/necropsy
Visceral organs histiocytes

93
Q

Which member of Phylum Apicomplexa is known for the predator-prey relationship in its host

A

Sarcocystis spp

94
Q

What clinical signs of Bovine Genital Trichomonosis is seen in cows?

A 
Vaginitis 
Cervicitis 
Endometriosis 
Pyometra
Mucopurulent discharge

Parasitology (4 decks)

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