Ectoparasites I: Tick-Borne Protozoa

Question 1

What are the canine Hepatozoon spp?

Answer 1

Hepatozoon americanum

Hepatozoon canis

Question 2

What is Hepatozoon americanum the causative agent?

Answer 2

American canine hepatozoonosis

Question 3

Where is Hepatozoon americanum found?

Answer 3

North America (southern US)
South and Central America

Question 4

What is the definitive host for Heptaozoon americanum?

Answer 4

Tick vector: Amblyomma maculatum (Gulf Coast Tick)

Question 5

What is the intermediate host for Hepatozoon americanum?

Answer 5

Canids

Question 6

What is the paratenic host for Hepatozoon americanum?

Answer 6

Rodents, rabbits

Question 7

What is the PPP for Hepatozoon americanum?

Answer 7

32 days

Question 8

How does the dog get infected with Hepatozoon americanum?

Answer 8

It ingests the tick

Question 9

Describe the indirect life cycle of Hepatozoon americanum

Answer 9

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

Question 10

Describe the cycle of Hepatozoon american for the paratenic host

Answer 10

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

Question 11

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

Answer 11

Ingests canine leukocytes with gamont

Question 12

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

Answer 12

Ingests tick with oocysts or PH with Cystozoites

Question 13

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

Answer 13

Mature oocysts in hemocoel

Question 14

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

Answer 14

Gamonts in leukocytes

Meronts in skeletal and cardiac muscle

Question 15

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

Answer 15

Cystozoites in skeletal and cardiac muscle, kidney, lung

Question 16

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

Answer 16

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

Question 17

What are the presumptive diganosis methods of ACH?

Answer 17

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

Question 18

What are the definitive diagnosis methods of ACH?

Answer 18

Gamonts in leukocytes
Muscle biopsy*
PCR
ELISA

Question 19

What is collected to find ACH gamonts?

Answer 19

Buffy coat in blood

Question 20

Where are onion skin cysts usually found?

Answer 20

In cardiac, skeletal muscle

Question 21

Describe pyogranulomas

Answer 21

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

Question 22

What is the treatment for ACH?

Answer 22

No treatment effective

Can be treated in acute cases

Question 23

What is the control method for ACH?

Answer 23

Reduce risk of exposure

Question 24

Describe Hepatozoon canis

Answer 24

Usually subclinical

–presentation different in US vs elsewhere

Question 25

What is the definitive host of Hepatozoon canis?

Answer 25

``` Tick vector Rhipicephalus sanguineus (brown dog tick) ```

Question 26

What is the intermediate host of Hepatozoon canis?

Answer 26

Canids

Question 27

What is the PH pf Hepatozoon canis?

Answer 27

Rodents

Question 28

What makes Hepatozoon canis different from H. americanum?

Answer 28

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

Question 29

Where is Cytauxzoon felis found?

Answer 29

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

Question 30

What is the DH for Cytauxzoon felis?

Answer 30

Tick vector (amblyomma americanum: Lone star tick)

Question 31

What is the IH for Cytauxzoon felis??

Answer 31

Felids (Bobcat are reservoirs)

Question 32

Describe the indirect life cycle of Cytauxzoon felis

Answer 32

``` 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 ```

Question 33

What is the PPP of Cytauxzoon felis?

Answer 33

1-3 weeks

Question 34

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

Answer 34

Merozoites from infected RBCs

Question 35

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

Answer 35

Sporozoite from infected tick or from blood transfusion

Question 36

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

Answer 36

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

Question 37

What is the pathology of Cytauxzoonosis?

Answer 37

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)

Question 38

What are the methods of diagnosing cytauxzoonosis?

Answer 38

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

Question 39

What is the treatment for cytauxzoonosis?

Answer 39

No efficacious treatment; poor prognosis

Question 40

What are methods of control for cytauzoonosis?

Answer 40

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

Question 41

Where is Babesia spp. found?

Answer 41

Worldwide

Question 42

What is the DH for Babesia?

Answer 42

Tick vector (wide range)

Question 43

WHat is the IH for Babesia?

Answer 43

Various wild and domestic animals (canids*); humans | Piroplasms in RBCs

Question 44

Describe the general Babesia life cycle

Answer 44

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

Question 45

What are the 3 main causes of canine babesiosis?

Answer 45

Babesisa canis vogeli B. gibsoni B. conrade

Question 46

Describe B. canis vogeli

Answer 46

Enzootic in US, especially South (Greyhound kennels) | DH: tick vector (Rhipicephalus sanguineus- brown dog tick)

Question 47

Describe B. gibsoni

Answer 47

In US, American Stafforshire and Pit Bulls | DH: tick vector

Question 48

Describe B. conradae

Answer 48

No breed predilection; California | DH: tick vector is unknown

Question 49

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

Answer 49

Bite from infected tick vector | Direct animal to animal (dog fights, Iatrogenic, transfusions, transplacental)

Question 50

What is the transmission of canine babesiosis to DH?

Answer 50

Blood meal from dog | Transovarial transmission

Question 51

What is the pathology for canine babesiosis?

Answer 51

Hemolytic anemia Thrombocytopenia Hemoglobinuria Hemoglobinemia

Question 52

What are clinical signs for canine babesiosis?

Answer 52

Splenomegaly

Question 53

What are the diagnostic methods for canine babesiosis?

Answer 53

Blood smears Antibody testing PCR

Question 54

What is the treatment for canien babesiosis?

Answer 54

Reduce parsitemia

Question 55

What is the control for canine babesiosis?

Answer 55

Decrease tick exposure Routine on-animal tick control Remove ticks

Question 56

What are the causes of bovine babesiosis?

Answer 56

B. bovis | B. bigemina

Question 57

What is the DH of bovine babesiosis?

Answer 57

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

Question 58

What is the IH of bovine babesiosis?

Answer 58

Cattle, other ruminants

Question 59

What are causes of Equine Piroplasmosis?

Answer 59

B. caballi | Theileria equi

Question 60

What is the DH of Equine Piroplasmosis?

Answer 60

Tick vector (Dermacentor, Hyalomma, Rhipicephalus)

Question 61

What is the IH of Equine Puroplasmosis?

Answer 61

Equids

Question 62

What are the clinical signs of Equine Piroplasmosis?

Answer 62

Theileria equi more severe | Chronic has subtle signs

Question 63

What is the IH of Feline Babesiosis?

Answer 63

Panthers, cougars

Question 64

What is the DH of Feline Babesiosis?

Answer 64

Tick species; unknown

Question 65

What is the cause of human babesiosis in the US?

Answer 65

Babesia microti

Question 66

What is the DH of Babesia microti?

Answer 66

Tick vector (Ixodes scapularis)

Question 67

What is the IH of Babesia microti?

Answer 67

Rodent (reservoir)

Question 68

What is the accidental host of Babesia microti?

Answer 68

Humans