vet-tech-animal-diseases-ch-1-pansystemic-diseases-2-part-2

• infectious, but not contagious
• caused by Rickettsia bacteria
• typically relying on vectors for transmission - ticks of various kinds depending on the disease
• can all look alike symptom-wise, but all are treated the same
• - can test for individual diseases, but 11 tick borne diseases lab work costs approx $175 to vet, $350 to client
• - 4DX test catches Lyme, Ehrlichia, Anaplasmosis
• cats don't usually get Rickettsial diseases

an order of gram negative bacteria occuring as elementary bodies that typically multiply only in the cytoplasm of host cells

• Rocky Mountain Spotted Fever
• Ehrlichiosis
• Borreliosis - Lymes
• Anaplasmosis

• Etiology - Rickettsia rickettsii
• Vector - Dermacentor variabilis (wood tick), also Brown Dog tick
• misnomer - primarily Ohio River Valley
• attacks vascular endothelial cells
• tick proboscis goes into capillary and spits anticoagulant and disease which attacks endothelium
• tends to be seasonal
• humans can contract this via ticks

• fever - approx 104-105
• anorexia - loss of appetite
• depression
• mucopurulent ocular discharge
• cough
• panting (tachypnea)
• vomiting/diarrhea
• hypersensitive to touch
• very uncomfortable
• muscle pain
• CNS signs
• severe weight loss
• retinal hemorrhages
• scrotal edema
• acute renal failure
• symptoms dependent on vessels most affected
• - every organ has endothelial cells
• eventually will cause vasculitis

• history
• - tick exposure
• season
• - spring and summer
• symptoms
• - rule out other tick borne diseases
• serology
• - screen for antibodies
• lab tests
• - anemia - because of leaking blood vessels
• - thrombocytopenia - getting used up repairing constantly damaged blood vessels
• - hypoproteinemia - protein leaks out of damaged blood vessels with blood

• Doxyclycline
• - one of the few antibiotics that crosses cell membrane and gets into cytoplasm
• - no dairy products or calcium rich foods with this; calcium interferes with absorption of drug
• - also:
• -- Tetracycline (oldest, 4x daily)
• -- Minacycline (1x day, newest, most expensive)
• -- Oxycycline, Doxycycline (reasonable cost, dosage schedule)
• -- Amoxicillin (also enters cytoplasm, but not as well)
• - slows rate of bacteria multiplication so that immune system can keep up with it
• supportive care
• length of treatment will vary dependent on vet's experience with the disease (no concensus)

• tick control
• - treatment does not remove all organisms
• no vaccine

• Etiology:
• - Ehrlichia canis
• - Ehrlichia ewingii
• - Ehrlichia equi (now Ehrlichia anaplasmosis)

• monocytes turn into macrophages; ehrlicia kills the cells that would destroy it
• Etiology:
• - Ehrlichia canis
• Vector - Rhipicephalous sanguineus (brown dog tick)
• disease has 3 distinct phases:
• - acute
• - subclinical
• - chronic

• in New England, usually catch it at this phase
• monocyte invasion
• 2-4 week duration
• clinical signs:
• - lymphadenopathy
• - fever
• - weight loss
• - edema
• - nasal and ocular discharge

• see this in dogs transported from the south
• few symptoms
• CNS signs - eg foot dragging, problems jumping

• owners see this as eyes loooking funny
• retinal hemorrhage
• extreme weight loss
• anterior uveitis - sparkle in penlight
• CNS signs
• bleeding tendencies
• secondary bacterial infections

• history
• - ticks
• physical exam
• - fever
• - symptoms
• serology
• - immunofluorescent antibody test (IFAT) - same kind of test for FeLV

• supportive care
• - fluids
• - transfusions
• Doxycycline

tick control

• granulocytes - neutrophils, basophils, eosinophils
• 2 forms with 2 different etiologies
• first form:
• - etiology - Ehrlichia ewingii
• - vector - Amblyomma americanum (Lone Star tick) - don't see a lot in New England
• - acute polyarthritis
• - inflammatory joint disease - endothelium of synovial joints
• second form:
• - etiology - Ehrlichia eui
• - vector - Ixodes damini (now scapularis) - same as for Lyme
• - severe lethargy and anorexia
• both cross reactive with ehrlichia canis

• positive for Ehrlichia canis
• abnormalities in granulocytes

Doxycycline

tick control

• etiology:
• - Borrelia burgdorferi
• - spirochete
• - not rickettsial, but similar symptoms; vector borne disease
• - changes surface proteins depending on environment (eg tick vs dog)
• vector:
• - Ixodes sp.
• - can use almost anything alive as host for any stage in life cycle; makes it hard to eradicate
• - must attach for a minimum of 48 hours
• disease of the Northeastern United States; unusual in the rest of the US
• endemic in Eastern Mass
• - widespread in wildlife with occassional flare up in dogs/humans

• - extremely variable
• - dermatologic - bullseye rash - rarely seen in animals because of fur
• - arthritic
• - cardiac
• - neurologic
• - nephritic - labrador retrievers - immune reaction, not the disease itself
• tends to like cells of cartilage (encased in clear substance)

• fever
• lethargy
• hyperesthesia
• polyarthritis
• dermatitis
• 80% of infections are asymptomatic

• episodic lameness
• myocardial abnormalities
• CNS signs
• acute renal failure

• history
• serologic testing - 3 tiered approach:
• - ELISA - antibody screening test (quantitative analysis)
• - C6 qualitative analysis - > 30 and symptomatic means you should treat (variable by vet for other #)
• - Cornell test - new chronic va acute

• symptomatic
• - positive snap
• - C6
• asymptomatic
• - positive snap
• - +/- C6 - depends on who you work for; even different vets in same practice
• doxycycline or amoxicillin
• - 2-12 weeks
• tends to recur
• likes chondrocytes (connective tissue cell - tissue that covers long bone)
• - very difficult to get antibiotics in there

• population of dogs that go into acute renal failure
• - dog is fine in AM
• - by PM won't eat, vomiting
• - take to vet
• - kidneys have failed, very high Lymes C6 (500-700 and up)
• - antibody/antigen complex
• -- when small, go through kidney and leave in urine
• -- when large, go to liver, get metabolized (broken down), go through kidney and leave in urine
• -- when intermediate (like Lymes), clog up glomeruli in kidney and eventually it fails
• - dog will die
• - happens in retrievers a lot
• - certain genotype (approx 30%) in humans have reactions

• tick control
• vaccination
• - OspA
• -- external proteins are form that are in tick gut
• -- older vax
• -- efficacy approx 70%
• - Osp C
• -- external proteins are form that are in dog
• -- efficacy 85%

• etiology - Anaplasma phagocytophilium (means phagocyte loving)
• was called - Ehrlichia equi
• granulocytic affinity
• see Canine Granulocytic Ehrlichiosis