Infectious Flashcards
(207 cards)
What kind of bacteria is Ehrlichia?
Intracellular
Gram-negative
How is Ehrlichia transmitted in the vector (tick)?
Trans-stadial transmission
Pathogen remains with vector from one life stage to another (but not from parent to eggs).
Who causes canine monocytic ehrlichiosis
E. canis
Which tick carries E. canis?
Rhipicephalus sanguineous (Brown dog tick)
Who causes Canine granulocytic ehrlichiosis?
E. ewingii
What tick carries E. ewingii (Canine granulocytic ehrlichiosis)?
Amblyomma americanum (lone star tick)
Who causes human monocytic ehrlichiosis
E. chaffeensis
True or false: Ehrlichia, Anaplasma and Neorickettsia are in the same family?
True
Rickettsiae is a separate family
What dog breed is more susceptible to E. canis with a worse prognosis?
German Shepherds
What is the pathogenesis of E. canis? (Canine monocytic ehrlichiosis)
- Organism multiplies within vacules in monocytes - lyse cells
- Immune-mediated mechanism
- Presence of spleen contributes to severity of disease
What are the phases of the disease for canine monocytic ehrlichiosis (E. canis)?
- Acute 8-20 days after infection, may resolve spontaneously.
- Subclinical - Organisms sequestered in spleen
- Chronic phase
- Can see pancytopenia from BM involvement
What are some secondary opportunistic infections with E. canis (canine monocytic ehrlichiosis)?
- Viral papillomatosis
- Protozoal infections
- Bacterial UTIs
What is a protein electrophoresis finding of E. canis?
Sometimes can have a monoclonal gammopathy => misdiagnosis of lymphocytic leukemia or multiple myeloma
What type of hypersensitivity reaction can you see with E. canis?
Type III hypersensitivity (Immune complex deposition) and protein losing nephropathy (glomerulonephritis)
What are some clinical signs of E. canis (canine monocytic ehrlichiosis)?
Fever, lethargy, splenomegaly, lymphadenopathy, anterior uveitis, neurologic CS
What are CBC findings of E. canis?
Thrombocytopenia!
Occasional mild leukopenia
Pancytopenia in chronic phase
Morulae in circulating monocytes
What are common chemistry findings of E. canis?
- Hyperglobulinemia (polyclonal most common, but can be monoclonal) with hypoalbuminemia.
- ALT/ALP elevations
- Azotemia if PLN
What is the gold standard diagnostic for Ehrlichia canis?
IFA (there is cross-reactivity)
What is the consensus treatment for E. canis?
Doxycycline 10mg/kg Q24h x 28d
Does Ehrlichia ewingii (Canine granulocytic ehrlichiosis) have a chronic phase?
NO
Only E. canis
What are symptoms for E. ewingii (Canine granulocytic ehrlichiosis)?
Usually NONE
Fever
Anorexia
Neutrophilic Polyarthritis
True or false: Dogs can be reservoir host for E. ewingii (canine granulocytic ehrlichiosis)
TRUE
What is the pathogen for human monocytic ehrlichiosis and what tick carries it?
- Ehrlichia chaffensis
2. Amblyomma americanum (lone star tick)
Diagnosis for E. ewingii is limited to:
ELISA, western blot, PCR
Can do IFA for E. canis only