Babesiosis

Question 1

Overview

Answer 1

Protozoal dz of dogs 
Merozoites (piroplasms) infect RBCs 
Degree of illness usually dependent on the severity and rate of development of anemia 
Anemia 
--Mainly DT IM-hemolysis 
--Also direct piroplasm damage to RBCs

Question 2

Etiology/Pathogenesis

Answer 2

Infection by:

• -tick transmission
• -transplacental
• -blood transfusion, blood transfer –> dog bites!

2 week incubation period –> piroplasms infect and multiple in RBCS –> RBCs damage (IM processes, direct RBC lysis)

Question 3

Etiology Dogs: Large Spp

Answer 3

Babesia canis - wwd 
3 subspecies based on distribution
--B canis vogeli - US, Africa, Asia, Australia 
--B canis rossi - Africa *most virulent*
--B canis canis - Europe, Asia

Question 4

Etiology Dogs: Small spp

Answer 4

B gibsoni - wwd. Main Babesia species to cause clinical dz in US
B conradae: dogs only in CA
Babesia (Theileria) annae reported in US

Question 5

Signalment

Answer 5

Hx of tick attachment 
Recent dog bite wound 
--risk for B gibsoni IFX
Any age/breed of dog can be infected 
Severity of dz depends on
--Strain of organism 
--Breed, age of animal

Question 6

CS

Answer 6

Peracute, acute, chronic, asymptomatic
Splenectomy, immunosuppresion - severely worsens dz, makes it apparent
Immunosuppression - may increase parasitemia and get CS in chronically infected dogs
Most severe dz in US –> B gibsoni
B canis –> rarely causes clinical dz

Question 7

CS #2

Answer 7

SYSTEMICALLY SICK DOG
–Lethargy, A, WL, pale MM, F
Splenomegaly
Lymphadenopathy
Hemoglobinemia/uria
Icterus
GI
–vomiting, diarrhea, +/- dark feces (increased bilirubin)

Question 8

CBC

Answer 8

Regen anemia - mild to severe 
Peracute - regenerative response has no time to occur 
Anemia - may not be present in carriers 
--Greyhounds w/ B canis 
THROMBOCYTOPENIA
--Usually moderate to severe 
--Can occur without anemia 
Variable leukocytosis or leukopenia

Question 9

Chem Panel

Answer 9

Hyperbilirubinemia/uria - rarely USA cases
Hemoglobinuria - less common in USA cases
Hyperglobulinemia - common in chronic cases
–Sometimes only blood chem abN
Mildly increased liver enzymes DT anorexia/hypoxia

Question 10

Other Lab Tests

Answer 10

Blood smear stained with modified Wrights stain
–definitive if see organisms
Can differentiate between large (canis) and small (gibsoni) in the USA
Rarely see organisms in chronic carriers
Blood collected from ear tip may improve sensitivity
–far more important in mycoplasma

Question 11

Serology

Answer 11

IFA
False negative results in young dogs
Does not differentiate species and subspecies
Surpassed by PCR

Question 12

PCR

Answer 12

EDTA Blood
Differentiates subspecies and species
More sensitive than microscopy

Question 13

Coombs’ Test

Answer 13

Usually positive in dogs with babesiosis

Need to distinguish from IMHA

Question 14

Therapy

Answer 14

Anemia - blood transfusion
Shock - aggressive fluid tx
–could be bleeding from thrombocytopenia

Question 15

Drugs B canis EXAM

Answer 15

Immidocarb can completely clear infection
–NOT FOR B GIBSONI!
Given by IM INJ –> painful
Other SE rare but has anticholinergic activity
–Hypersalivation, nasal drip, shivering, increased lacrimation, diarrhea, vomiting, periorbital edema

Question 16

Drugs B gibsoni EXAM

Answer 16

Azithromycin, atovaquone
NOT FOR B CANIS
Only instance in SA where use Atovaquone (also good for Cytaux in cats)

Question 17

Additional Comments

Answer 17

Babesia found in 1 dog from a kennel –> screen all other dogs
Consider co-IFX with other vector-transmitted pathogens
Vax for B canis in Europe don’t work in the states
Tick control important for dz prevention
Screen blood donors –> negative by 2-3 PCR
–Babesia = 3
–Mycoplasma = 2