Ectoparasites I: Tick-Borne Protozoa Flashcards

1
Q

What are the canine Hepatozoon spp?

A

Hepatozoon americanum

Hepatozoon canis

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2
Q

What is Hepatozoon americanum the causative agent?

A

American canine hepatozoonosis

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3
Q

Where is Hepatozoon americanum found?

A
North America (southern US)
South and Central America
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4
Q

What is the definitive host for Heptaozoon americanum?

A

Tick vector: Amblyomma maculatum (Gulf Coast Tick)

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5
Q

What is the intermediate host for Hepatozoon americanum?

A

Canids

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6
Q

What is the paratenic host for Hepatozoon americanum?

A

Rodents, rabbits

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7
Q

What is the PPP for Hepatozoon americanum?

A

32 days

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8
Q

How does the dog get infected with Hepatozoon americanum?

A

It ingests the tick

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9
Q

Describe the indirect life cycle of Hepatozoon americanum

A

Mature oocysts in tick hemocoel
Dog ingests tick with oocysts
Sporozoites penetrate intestine, circulate, and enter tissue
Merozoites released from mature meronts
Gamonts form
Tick ingests leukocytes containing gamonts

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10
Q

Describe the cycle of Hepatozoon american for the paratenic host

A

PH ingests tick
Cystozoites in PH tissues
Dog ingests ticks on PH or PH with cystozoites

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11
Q

What are the Hepatozoon americanum infective stages in the tick vector (DH)?

A

Ingests canine leukocytes with gamont

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12
Q

What are the Hepatozoon americanum infective stages in the dog (IH)?

A

Ingests tick with oocysts or PH with Cystozoites

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13
Q

What is the site of infection for Hepatozoon americanum in the tick vector (DH)?

A

Mature oocysts in hemocoel

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14
Q

What is the site of infection for Hepatozoon americanum in the dog (IH)?

A

Gamonts in leukocytes

Meronts in skeletal and cardiac muscle

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15
Q

What is the site of infection for Hepatozoon americanum in the PH?

A

Cystozoites in skeletal and cardiac muscle, kidney, lung

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16
Q

What is the pathology of American Canine Hepatozoonosis (ACH)?

A
Neutrophilic leukocytosis (moderate anemia)
Periosteal bone proliferation (primarily long bones, primarily younger dogs)
Tissue lesions (onion skin cyst*, pyogranulomas)
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17
Q

What are the presumptive diganosis methods of ACH?

A

Profound neutrophilia
Periosteal bone lesions (extension/thickening of long bones)
Clinical signs, history

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18
Q

What are the definitive diagnosis methods of ACH?

A

Gamonts in leukocytes
Muscle biopsy*
PCR
ELISA

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19
Q

What is collected to find ACH gamonts?

A

Buffy coat in blood

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20
Q

Where are onion skin cysts usually found?

A

In cardiac, skeletal muscle

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21
Q

Describe pyogranulomas

A

Rupture of cyst with mature meront— merozoites released, inflammatory cell infiltration

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22
Q

What is the treatment for ACH?

A

No treatment effective

Can be treated in acute cases

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23
Q

What is the control method for ACH?

A

Reduce risk of exposure

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24
Q

Describe Hepatozoon canis

A

Usually subclinical

–presentation different in US vs elsewhere

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25
Q

What is the definitive host of Hepatozoon canis?

A
Tick vector
Rhipicephalus sanguineus (brown dog tick)
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26
Q

What is the intermediate host of Hepatozoon canis?

A

Canids

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27
Q

What is the PH pf Hepatozoon canis?

A

Rodents

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28
Q

What makes Hepatozoon canis different from H. americanum?

A

Higher number of WBCs infected
Meronts are in lymph nodes, bone marrow, spleen
Meront look like “wheel spoke” meronts
Dogs usually asymptomatic unless immunocompromised
Good prognosis with treatment
PH has monozoic cyst

29
Q

Where is Cytauxzoon felis found?

A

North America: southeaster, South-Central, Mid-Atlantic states

30
Q

What is the DH for Cytauxzoon felis?

A

Tick vector (amblyomma americanum: Lone star tick)

31
Q

What is the IH for Cytauxzoon felis??

A

Felids (Bobcat are reservoirs)

32
Q

Describe the indirect life cycle of Cytauxzoon felis

A
Tick bites cat
Sporozoites injected
Sporozoites invade endothelial-associated mononuclear phagocytes, replicate, develop into "schizonts"
Merozoites released from schizonts
Merozoites enter RBCs (piroplasma)
Nymphal tick feed on infected cat; ingests merozoites
Merozoites mature to gamtes
Sporozoites move to tick salivary gland
33
Q

What is the PPP of Cytauxzoon felis?

A

1-3 weeks

34
Q

What are the infective stages of Cytauxzoon felis in the DH?

A

Merozoites from infected RBCs

35
Q

What are the infective stages of Cytauxzoon felis in the IH?

A

Sporozoite from infected tick or from blood transfusion

36
Q

What are the sites of infection for Cytauxzoon felis in the IH?

A

Merozoites in RBCs

Schizonts in macrophages associated with endothelium of lung, liver, lymph node, spleen, bone marrow

37
Q

What is the pathology of Cytauxzoonosis?

A

Leukopenia; thrombocytopenia; non-regenerative anemia; elevated liver enzymes
Progressive illness (multiple organ failure)
2 phases:
1. Leukocytic (schizont; primary cause of clinical disease)
2. Erythrocytic (merozoites; RBC hemolysis)

38
Q

What are the methods of diagnosing cytauxzoonosis?

A

Clinical signs, history
Merozoites in stained blood smears
Schizonts in macrophages (bone marrow, lymph node, spleen aspirates; impression smears, biopsy material)

39
Q

What is the treatment for cytauxzoonosis?

A

No efficacious treatment; poor prognosis

40
Q

What are methods of control for cytauzoonosis?

A

Reduce tick exposure
Routine on-animal tick control
Remove tick immediately

41
Q

Where is Babesia spp. found?

A

Worldwide

42
Q

What is the DH for Babesia?

A

Tick vector (wide range)

43
Q

WHat is the IH for Babesia?

A

Various wild and domestic animals (canids*); humans

Piroplasms in RBCs

44
Q

Describe the general Babesia life cycle

A

Infected tick transmits sporozoites to vertebrate host via tick saliva
Sporozoites invade RBCs— develop and asexually replicate— merozoites
Ticks get infected by biting infected vertebrate- ingests RBCs

45
Q

What are the 3 main causes of canine babesiosis?

A

Babesisa canis vogeli
B. gibsoni
B. conrade

46
Q

Describe B. canis vogeli

A

Enzootic in US, especially South (Greyhound kennels)

DH: tick vector (Rhipicephalus sanguineus- brown dog tick)

47
Q

Describe B. gibsoni

A

In US, American Stafforshire and Pit Bulls

DH: tick vector

48
Q

Describe B. conradae

A

No breed predilection; California

DH: tick vector is unknown

49
Q

What is the transmission of canine babesiosis to canids in US?

A

Bite from infected tick vector

Direct animal to animal (dog fights, Iatrogenic, transfusions, transplacental)

50
Q

What is the transmission of canine babesiosis to DH?

A

Blood meal from dog

Transovarial transmission

51
Q

What is the pathology for canine babesiosis?

A

Hemolytic anemia
Thrombocytopenia
Hemoglobinuria
Hemoglobinemia

52
Q

What are clinical signs for canine babesiosis?

A

Splenomegaly

53
Q

What are the diagnostic methods for canine babesiosis?

A

Blood smears
Antibody testing
PCR

54
Q

What is the treatment for canien babesiosis?

A

Reduce parsitemia

55
Q

What is the control for canine babesiosis?

A

Decrease tick exposure
Routine on-animal tick control
Remove ticks

56
Q

What are the causes of bovine babesiosis?

A

B. bovis

B. bigemina

57
Q

What is the DH of bovine babesiosis?

A

Tick vectors (rhipicephalis microplus and annulatus; erradicated from US)

58
Q

What is the IH of bovine babesiosis?

A

Cattle, other ruminants

59
Q

What are causes of Equine Piroplasmosis?

A

B. caballi

Theileria equi

60
Q

What is the DH of Equine Piroplasmosis?

A

Tick vector (Dermacentor, Hyalomma, Rhipicephalus)

61
Q

What is the IH of Equine Puroplasmosis?

A

Equids

62
Q

What are the clinical signs of Equine Piroplasmosis?

A

Theileria equi more severe

Chronic has subtle signs

63
Q

What is the IH of Feline Babesiosis?

A

Panthers, cougars

64
Q

What is the DH of Feline Babesiosis?

A

Tick species; unknown

65
Q

What is the cause of human babesiosis in the US?

A

Babesia microti

66
Q

What is the DH of Babesia microti?

A

Tick vector (Ixodes scapularis)

67
Q

What is the IH of Babesia microti?

A

Rodent (reservoir)

68
Q

What is the accidental host of Babesia microti?

A

Humans