Condensed - tick born diseases Flashcards
what causes anaplasmosis?
Describe the pathogen?
What tick transmits this?
anaplasma phagocytophilum
gram negative: obligate intracellular bacteria
Tick - ixoides
how does anaplasma cause disease?
Granulocytic anaplasmaosis
Transmitted by ixodes tick species. A. phagocytophilum will enters neutrophil by interacting via P-selecting glycoprotein ligand-1. Will also cause mild thrombocytopenia.
Anaplasma Cx, Dx, Tx, prognosis
Cx;
No clinical signs – majority of animals
Mild febrile illness characterized by lameness, lethargy & fever
Dx;
Should be suspected if acute febrile illness with thrombocytopenia in an endemic area:
- CDC criteria for diagnosis of granulocytic anaplasmosis;
1) Detection of morulae within neutrophils
2) A 4 x increase in antibody titers
3) Positive PCR test results
4) Isolation of A. phagocytophilum from the blood
- CBC: most common findings: thrombocytopenia (90%)
Tx
- Doxycycline
Prognosis
No single instance of mortality ever reported. Long term immunity is suspected as there is currently no documentation of re-infection
what form of anaplasma most commonly forms thrombocytopaenia?
Anaplasma Platys in dogs -> cyclic thrombocytopaenia
What is erlichiosis caused by and how is this transmitted ?
breed which is most SEVERELY affected ?
ehrlichia canis transmitted by the brown dog tick (Rhipichephalus sanguineus).
German shepherd seems to be predisposed to more severe illness
What are the phases of disease in erlichia?
Define these
Acute phase:
- Fever, lethargy, lymphadenomegaly
- Ocular abnormalities (e.g., uveitis)
- Neurological abnormalities (e.g., twitching, ataxia, seizures)
- Bleeding tendency
Chronic phase:
If the patient moves to the chronic phase of illness, ehrlichia will cause;
- profound bone marrow suppression and hypoplasia.
- In some patients, there is the development of a severe plasmacytosis and associated monoclonal gammopathy which can be misdiagnosed as leukemia or multiple myeloma.
- Clinical features: diffuse muscle wasting, pallor
How to differentiate erlichia from leukemia or multiple myeloma ?
See gammopathy bellow
Benz hones associated with multiple myeloma, although, technically any increase in Ig’s should cause this
Ehrlichiosis can cause glomerulonephropathy, a kidney disease that can sometimes lead to the appearance of Bence Jones proteins. However, in most cases, ehrlichiosis is not the underlying cause of Bence Jones proteinuria,
Erlichia Cx, Dx, Tx, prognosis
Canine monocyte erlichiosis (CME)
Cx
Acute phase:
- Fever, lethargy, lymphadenomegaly
- Ocular abnormalities (e.g., uveitis)
- Neurological abnormalities (e.g., twitching, ataxia, seizures)
- Bleeding tendency
Chronic phase:
- bone marrow suppression and hypoplasia
- monoclonal gammopathy -> hyperviscocity syndrome
Dx
Complete blood count:
- thrombocytopenia (most common in acute phase)
- pancytopenia (is the hallmark of chronic CME)
Biochem
- Hypoalbuminemia and hyperglobinemia; this can be due to a monoclonal gammopathy
Microbio testing’
- Gold standard: immunofluorescence (IFA) – gold standard for the diagnosis of canine monocytic ehrlichiosis. Chronic ehrlichiosis will have extremely high titer levels: 1:160 000
- 4Dx
Tx
- Doxycycline 10 mg/kg PO q 28 days
Prognosis
Negative prognostic indicators: severe leukopenia, severe anemia (Hct < 11%), hypokalemia, and aPTT
what are negative prognostic indicators for erlichiosis
Negative prognostic indicators: severe leukopenia, severe anemia (Hct < 11%), hypokalemia, and aPTT
