Tick Transmitted Dzs

Question 1

Ehrlichia canis produced morulae in what type of cell?

Answer 1

(Monocytes hence the name canine monocytic ehrlichiosis, but also lymphocytes)

Question 2

Ehrlichia canis is primarily transmitted by which tick? Common name and scientific.

Answer 2

(Brown dog tick, Rhipicephalus sanguineus)

Question 3

Where are brown dog ticks found in the US?

Answer 3

(Everywhere but do prefer warm climates)

Question 4

When can the acute phase of CME occur after a brown dog tick bite and what are the main conditions of concern associated with the acute phase?

Answer 4

(The acute phase can begin 8-20 days post inoculation and the main conditions of worry associated with the acute phase are thrombocytopenia and/or thrombocytopathia; also see fever, lethargy, inappetence, lymphadenomegaly, hepatosplenomegaly, peripheral edema, uveitis/retinal dz, and neurologic signs from meningeal inflammation and/or CNS hemorrhage)

Question 5

Besides an animal with acute canine monocytic ehrlichiosis/CME progressing to chronic CME, what else can occur?

Answer 5

(They can eliminate the infection entirely on their own or remain subclinically infected (they will not have any signs but will test positive))

Question 6

What are the main conditions of concern associated with the chronic phase of canine monocytic ehrlichiosis?

Answer 6

(Bone marrow hypoplasia (will translate to pancytopenia on bloodwork), marked lymphocytosis (which can look like leukemia or lymphoma), and bone marrow plasmacytosis resulting in hyperglobulinemia (which can look like multiple myeloma); also see similar signs to acute phase, protein losing nephropathy/glomerulonephritis, and polymyositis)

Question 7

How can you increase the sensitivity of a blood smear or what can you FNA and perform cytology on to increase sensitivity for E. canis morulae?

Answer 7

(You can smear the buffy coat of a blood sample or you can FNA a lymph node or the spleen)

Question 8

The chance of a false negative for an antibody test for E. canis increases with an acute/chronic (choose) infection.

Answer 8

(Acute)

Question 9

What is the gold standard test for E. canis?

Answer 9

(IFA)

Question 10

What is the difference in the most sensitive test option for an acute versus a chronic CME infection?

Answer 10

(Whole blood PCR is more appropriate for an acute infection whereas serological testing (IFA) is more appropriate for a chronic infection)

Question 11

What is the treatment of choice for CME and what two other drugs can be used as alternatives?

Answer 11

(Doxycycline is the drug of choice, minocycline or chloramphenicol can be used in its stead)

Question 12

Ehrlichia chaffeensis is transmitted by what tick? Common and scientific name.

Answer 12

(Lone Star tick, Amblyomma americanum)

Question 13

You are presented with a neutrophil with a morula and a dog with polyarthritis, which diseases are a possibility and how would you go about distinguishing between them?

Answer 13

(Anaplasma phagocytophilium and Ehrlichia ewingii are both possible, can use PCR and/or serology testing to differentiate, begin treatment while you wait for results!)

Question 14

Ehrlichia ewingii is transmitted by what tick? Common and scientific name.

Answer 14

(Lone Star tick, Amblyomma americanum)

Question 15

(T/F) As of this moment, E. ewingii is only known to cause acute forms of disease.

Answer 15

(T)

Question 16

Anaplasma phagocytophilium is transmitted by what tick(s)? Common and scientific name.

Answer 16

(Deer tick or black-legged tick, Ixodes scapularis (east + mid) and Ixodes pacificus (west))

Question 17

Rickettsia rickettsii is transmitted by what tick(s)? Common and scientific name.

Answer 17

(Wood tick, Dermacentor andersoni (west) and American dog tick, Dermacentor variabilis (east + mid))

Question 18

Where does Rickettsia rickettsii replicate in the body?

Answer 18

(Endothelial cells of smaller arteries and venules)

Question 19

Hepatozoon americanum is transmitted by what tick? Common and scientific name.

Answer 19

(Gulf Coast tick, Amblyomma maculatum; remember it needs to be INGESTED by the animal)

Question 20

What are the main bloodwork changes you expect to find for a dog with hepatozoonosis?

Answer 20

(Waxing and waning elevated leukocyte count, increased ALP from periosteal inflammation, and hypoglycemia (bc the WBCs in the sample will metabolize the glucose, a real time test with a BG monitor will be normal))

Question 21

A clinical feature of hepatozoonosis in dogs is periosteal bone proliferation, this occurs more frequently with which bones of the body?

Answer 21

(The proximal limb bones)

Question 22

What might you see on a blood smear in a dog with hepatozoonosis?

Answer 22

(H. americanum gamots in leukocytes)

Question 23

What is the most reliable way of confirming a H. americanum diagnosis and what do you expect to see?

Answer 23

(Skeletal muscle biopsy, lesions are “onion” cysts and pyogranulomatous myositis)

Question 24

What is the treatment protocol for hepatozoonosis?

Answer 24

(TCP (TMS, clindamycin, and pyrimethamine) combo therapy for 2 weeks followed by decoquinate for 2 years)

Question 25

Where will you look for signs of Babesia canis in an infected patient’s blood smear?

Answer 25

(Erythrocytes)

Question 26

Babesia canis is transmitted by what tick? Common and scientific name.

Answer 26

(Brown dog tick, Rhipicephalus sanguineus)

Question 27

What are the two more important clinical features of canine babesiosis?

Answer 27

(Thrombocytopenia and hemolytic anemia, also causes fever, inappetence, lethargy, lymphadenomegaly, and splenomegaly)