Companion Animal Pathogens Flashcards
(49 cards)
List 9 Vector born Bacterial Pathogens
Vector born Bacterial Pathogens
* Rickettsia rickettsia
* Anaplasma phagocytophilum
* Ehrlichia canis
* Neorickettsia helminthoeca
* Mycoplasma hemofelis
* Borrelia burgdorferi
* Bartonella henselae
* Francisella tularensis
* Yersinia pestis
List the 4 main rickettsiales? What are their common features?
Rickettseiales
* Obligate intracellular parasite
* Gram (-) rod
o Anaplasatacae lack part of the cell wall
* Cant culture
* Associated with ticks
Rickettsia rickettsia
Anaplasma phagocytophilum
Ehrlichia canis
Neorickettsia helminthoeca
List the vector, cell preference, host, and disease caused by Rickettsia rickettsia
- Vector: tick (Dermacentor spp.)
o Transmission required minimum attachment of 6-20h
o Nymphs can transmit (transovarial transmission can occur) - Cell preference: endothelium
- Host: dogs/human
- Disease: rocky mountain spotted fever
What is the incubation time and clinical signs of Rickettsia rickettsia
- Incubation: 2-14d
o Fever (most consistent finding)
o Early cutaneous lesions: edema/hyperemia
o Petechia/ecchymoses on MM
o Myalgia/joint pain/swelling
o Neurologic signs
o Necrosis (due to vasculitis)
What are the virulence factors of Rickettsia rickettsia
- Virulence
o Adhesion = outer membrane protein A (attach too receptor of host cell)
o Phospholipase D lyse vacuole inside cell to escape into cytosol
o Cell-cell spread = vasculitis (hallmark)
o Cell mediated immunity = apoptosis oof infected cells = endothelial injury
o = lymphohistiocytic vasculitis
What is the pathogenesis of Rickettsia rickettsia
- Pathogenesis
o Enter via bite f infected tick
o Disseminated in blood
o Invade and replicate in endothelium in small arteries/venules
o Cause vasculitis and perivasculitis
o Increase vascular permeability = edema and DIC
o Hypotension = shock/petechiae/organ damage
Renal failure
CNS damage due to brain edema
How to diagnose Rickettsia rickettsia? What samples?
o Sample: blood/serum/cutanous biopsy
o Test: serology (best) – need 4 fold seroconversion
/IHC/PCR
Not culture (need BSL3 lab)
How to treat Rickettsia rickettsia?
- Tx: doxycycline
List the vector, cell preference, host, and disease caused by Anaplasma phagocytophilum
- Vector: tick (ixodes spp.)
o Need 36-48h of attachment - Cell preference: granulocytes
o Forms membrane-enclosed morulae - Host: dogs
o Also cat/human/ruminant/horse/camelid
o Reservoir: deer/rodent/chipmunk/vole - Disease: tick borne fever
What is the incubation time and clinical signs of Anaplasma phagocytophilum
- Incubation: 14-20d
- Clinically
o Acute fever/lethargy/weak/inappetence
o Generalized lymphadenopathy/splenomegaly
What is the lifecycle/pathogen of Anaplasma phagocytophilum
- Lifecycle
o Attach to P-selectin glycoprotein on neutrophil
o Enter neutrophil via cavaeole mediated endocytosis
o Dysregulate neutrophil function and bypass phagolysosome
o Inhibit superoxide production and neutrophil motility
o Reduce neutrophil transmigration into tissues (more stay in circulation)
List the vector, cell preference, host, and disease caused by Ehrlichia canis
- Vector: ticks (rhiipicephalus/dermacentor – brown dog tick mainly)
- Cell preference: monocyte/macrophage
o Form membrane enclosed morulae - Host: dog
o Reservoir: also canids - Disease: canine monocytic erlichioosis
What is the pathogenesis of Ehrlichia canis
- Pathogenesis
o Mononuclear cells attracted to tick bites
o Carried to LN and escape into circulation
o Localize in ln/spleen/liver
o Replicate in macrophage/monocyte
o Cause lung hemorrhage/epistaxis and vasculitis/thrombocytopenia
What is tthe incubation and clinical signs of Ehrlichia canis
- Incubation: 8 – 20d
o Phase 1: 8-20d = acute
Fever/anorexia/enlarged LN/dyspnea = spontaneously resolve
o Phase 2; 2-4 months = subclinical
Immunocompetent dogs will eliminate infection
o Phase 3: fail to eliminate = chronic
GSD =more severe
Hemorrhage/epistaxis/peripheral edema
Hyphemia/blind/retinal detachment
How to diagnose Ehrlichia canis
- Dx: blood smear + cytology
List the vector, cell preference, host, and disease caused by Neorickettsia helminthoeca
- Vector: liver fluke
- Cell preference: RBC
- Host: dog
o Reservoir: #1 = snails, #2 = freshwater fish (salmon)
o Ingestion of liver fluke from fish
o Very fatal in dogs
o Will shed lots of fluke eggs - Disease: salmon poisoning
What is the incubation period and clinical signs of Neorickettsia helminthoeca
- Incubation: 2-14d (up to 1 month)
- Clinically
o Local granulomatous reaction on GI mucosa
o Peripheral lymphadenopathy
o Fever 5-7d after ingestion
o Diarrhea/v+ after 2 weeks
o Anorexia and wasting
o Death 18d after ingestion
How is Neorickettsia helminthoeca diagnosed (sample? test?)
o Sample: LN aspirate
o Cytology
How are Anaplasmataceae diagnosed (samples? tests?)
Anaplasmataceae
* Sample
o Blood – cytology
o Serum – antibody testing/ELISA
o Aspirate – histo/PCR
o Fecal – feces float
What does the 4Dx SNAP test evaluate for
- 4Dx SNAP ELISA
o Ehrlichia
o Borriella
o Anaplasma
o Dirofilarial
o Should confirm with PCR/serology
How to treat rickettsiales
Rickettsiales
* Tx; doxycycline (mainly)
o Praziquantel (kill flukes)
o Antiemetic
o Fluids
How to prevent rickettsiales
- Control/Prevent
o Remove ticks
o Tick prevention tx
o Prevent from eating rotting carcasses (fish)
List the vector, cell preference, host, and disease caused by Mycoplasma hemofelis
Hemotropic Mycoplasma: feline infectious anemia
Mycoplasma hemofelis
* Vector: ticks/flea
o Oral/bite wounds
* Cell preference: RBC
o Adhere to surface of RBC
* Host: cats mainly (hemocanis – dogs)
What is the pathogenesis of Mycoplasma hemofelis
- Pathogenesis
o Depressions formed by attachment leads to fraaggility of cells
o Macrophages removed from surface of RBC
o Autoimmune rxn – parasite RBC antigen complex = immune mediated osmotic fragility
