Tick-Transmitted Diseases

Question 1

What is one of the most common causes of petechiae in dogs?

Answer 1

Thrombocytopenia

*Bonus points if you also listed thrombocytopathia & endothelial dysfunction (vasculitis) as differentials

Question 2

Typically see petechiae when platelets are less than what value?

Answer 2

<50,000

Question 3

What type of cells are morulae from Ehrlichia canis found in?

Answer 3

Monocytes (primarily) or lymphocytes

Question 4

Ehrlichia canis is primarily transmitted by which tick species?

Answer 4

Rhipicephalus sanguineus (brown dog tick)

Question 5

What are some common clincial findings found in the acute phase of a dog infected with E. canis?

Answer 5

• Thrombocytopenia & thrombocytopathia
• Fever, lethargy, inappetance (most common)
• Lymphadenomegaly & hepatosplenomegaly

Question 6

What are some clinical findings associated with the chronic phase of E. canis?

Answer 6

• Same as acute phase
  + Bone marrow hypoplasia (pancytopenia)
• Marked lymphocytosis
• Bone marrow plasmacytosis -> hyperglobulinemia

Question 7

What is the gold standard test for detecting E. canis?

Answer 7

Indirect immunofluorescent antibody (IFA) test

Question 8

When detecting acute/active infections of E. canis, you perform 2 consecutive IFA tests, 7-14 days apart, and look for a ________-fold increase.

Answer 8

Four-fold

Question 9

Whole blood PCR is more sensitive for acute/chronic (choose one) infections of E. canis, whereas serology is more sensitive for acute/chronic infections.

Answer 9

Acute, chronic