This document summarizes common blood parasites found in dogs and cats, including Ehrlichia, Anaplasma, Babesia, Cytauxzoon, hemoplasmas, Hepatozoon, and Trypanosoma. It describes the clinical signs, diagnosis, and treatment for each parasite. Key information provided includes the life cycles, hosts, transmission methods, affected blood cell types, common lab abnormalities, recommended diagnostic tests such as blood smears and PCR, and treatment protocols.

1. COMMON BLOOD PARASITES
IN DOGS AND CATS
Dr. Abhishek Kalundia
B.V.Sc. & A.H., M.V.Sc., Ph.D. (pursuing)
The Alpha and Omega Pet Hospital
Hyderabad, Telangana State – 10
India

2. List of Blood parasite and their primary hosts
Veterinary Practice
1. Ehrlichiosis & Anaplasmosis (Dogs and Cats)
2. Babesiosis (Dogs)
3. Cytauxzoonosis (Cats)
4. Hemotropic mycoplasma (Dogs and Cats)
5. Hepazoonoses (Dogs)
6. Trypanosomiasis (Dogs)
7. Schistosomiasis (Cattle)
8. Theileriases (Cattle)

3. Anaplasmataceae family -
Ehrlichia, Anaplasma, and Neorickettsia
 Anaplasma traditionally refers to a disease of ruminants.
 Obligate intraerythrocytic bacteria of the order Rickettsiales.
 A phagocytophilum - formerly known as both E equi -
predominantly in granulocytes.
 A platys - infectious cyclic thrombocytopenia of dogs - platelets.
 Ehrlichia canis - Canine monocytic ehrlichiosis- human
infection occasionally reported - monocytes .
 E chaffeensis - monocytic form of illness in dogs.
 E ewingii - primarily infects the granulocytes.
 E muris–like (EML) agent - possible pathogen of dogs or cats -
currently unknown.

4. Epidemiology
 E chaffeensis and E
ewingii have sylvan cycles
in the environment that
involve tick species
(Amblyomma
americanum/lone star tick),
dogs and wildlife reservoir
hosts.
 EML - Ixodes scapularis
(black-legged tick)
 A phagocytophilum - Ixodes
scapularis (black-legged
tick)
 A platys - R sanguineus -
Coinfection with E canis
(same tick vector).
E chaffeensis, E ewingii, and A
phagocytophilum are considered
zoonoses.

5. Clinical Findings
Acute E canis Chronic E canis
 Warmer months- greatest activity of the tick vector
 Depending on the strain of organism and immune
status of the host.
 Reticuloendothelial hyperplasia
 Fever
 Generalized Lymphadenopathy
 Splenomegaly
 Thrombocytopenia (Petechiae May Not Be
Evident)
 Normochromic Anemia; Leukopenia; Or Mild
Leukocytosis.
 Vasculitis and tendecies of IMHA/IMTP.
 Variable signs of anorexia, depression, loss of
stamina, stiffness and reluctance to walk, edema of
the limbs or scrotum, and coughing or dyspnea may
be seen.
 Cases May Present At Any Time
Of Year.
 Marked Splenomegaly
 Glomerulonephritis - Renal
Failure
 Interstitial Pneumonitis
 Anterior Uveitis
 Meningitis With Associated
Cerebellar Ataxia, Depression,
Paresis, And Hyperesthesia.
 Severe Weight Loss
 Pancytopenia With Bleeding
tendencies
Dogs infected with A platys generally show minimal to no signs of infection despite
the presence of the organism in platelets. The primary finding is cyclic
thrombocytopenia, recurring at 10-day intervals.

6. Diagnosis Treatment
 Combination Of
1. Clinical Signs
2. Positive Serum Indirect
Fluorescent Antibody (IFA)
Titer
3. PCR
4. Response To Treatment
 Doxycycline in dogs is 5–
10 mg/kg/day, PO or IV, for
10–21 days
 Two doses of Imidocarb
Dipropionate (5–7 mg/kg,
IM), 2 wk apart
 Supportive therapy -
Platelet or Whole Blood
Transfusions - if
hemorrhage is extensive.

7. Babesiosis
 Intraerythrocytic protozoan parasites of the genus Babesia.
 Clinical disease in dogs is variable and can be sublinical, chronic,
or life threatening.
 Large and small—based on intraerythrocytic form
A. Large (3–7 µm long; Single or pair tear-drop forms)
a. B gibsoni: worldwide
b. B conradae: southern California only
c. B microti-like: Spain
B. Small (1–3 µm long; Signet-ring form)
a. B canis vogeli: worldwide
b. B canis canis: Europe
c. B canis rossi: South Africa
d. B coco: United States

8. Pathology
 Intra- and extravascular
destruction of RBCs or
direct parasitic injury or
subsequent oxidative
stress or IMHA =
Hemolytic anemia
 IMTP or DIC =
Thrombocytopenia
 Lethargy
 Pale mucous
membranes with icterus
 Splenomegaly
 pyrexia

9. PERIPHERAL Blood Smear
Canine blood smear of Babesia canis showing
paired large merozoites (pair tear-drop forms)
Canine blood smear of Babesia gibsoni
showing single merozoites (signet-ring form).

10. Diagnosis Treatment
 Thrombocytopenia is the most
common feature regardless of
the babesia spp.
 Macrocytic anemia
 Hyperglobulinemia
 Hyperbilirubinemia,
 Increased liver enzyme
activities, azotemia
 Multiplex PCR (to rule out
coinfection), and DNA
sequencing
 Imidocarb dipropionate (6.6 mg/kg
IM once, repeat in 7–14 days) -
Treatment of choice for B canis
vogeli (but is ineffective for
clearance of B gibsoni and B
conradae)
 Pretreatment with Atropine (0.02
mg/kg SC 30 minutes before
imidocarb) reduces cholinergic side
effects (ie, salivation, lacrimation,
vomiting, diarrhea, tachycardia,
dyspnea)
 Clindamycin (25 mg/kg PO q12h),
+ Metronidazole (15 mg/kg PO
q12h), + Doxycycline (5 mg/kg PO
q12h) have been associated with
clearance of B gibsoni after
administration for ~3 months - true
treatment efficacy is unknown.
 Diminazene aceturate (3.5–7
mg/kg SC or IM q1–2wk) is
effective against B canis.

11. Cytauxzoonosis
 Emerging, life-threatening infectious disease
of domestic cats (and dogs) - tick-transmitted
protozoan parasite Cytauxzoon felis.
 Cytauxzoon spp are classified as part of the
family Theileriidae (includes Babesia and
Theileria organisms)
 Dermacentor ticks

12. Blood film from a cat
A – 10X
The leukocyte count is decreased, and neutrophils
exhibit Döhle bodies and increased cytoplasmic
basophilia and vacuolation consistent with
moderate to marked toxic change (broken arrows).
B – 40X
Erythrocytes show several small signet-
ring basophilic intracellular organisms
consistent with Cytauxzoon organisms
(arrows).

13. Cytauxzoonosis
Diagnosis Treatment
 Anorexia, Dehydration, Pallor,
and Icterus are common.
 Temperatures >105°F
 Ataxia
 Peripheral blood smear stain
(Giemsa)
 Nonregenerative Anemia,
Leukopenia, and
Thrombocytopenia due to DIC
 Hepatosplenomegaly, Pulm
Congestion or Cardiomegaly
with effusion.
 Controversial- infection is
fatal
 Supportive - aggressive IV
fluid therapy + blood
transfusions + Enoxaparin
to prevent DIC.
Medications
 Standard of treatment has
yet to be determined.

14. Hemotropic Mycoplasmas
 Previously known as Haemobartonella and Eperythrozoon and
formerly classified as Rickettsial organisms.
 Clinically significant Hemolytic Anemia - FELINE
INFECTIOUS ANEMIA (FIA)
 REGENERATIVE ANEMIA IN DOGS AND CATS

15. Hemotropic Mycoplasmas
Transmission Clinical signs
 Blood transfusion
 Verticle transmission
(transuterine)
 Horizontal transmission
(saliva, on gingiva, and on
claw beds of infected cats)
 Vector borne (lice, flies,
ticks, and mosquitoes)
 Coinfection with multiple
hemoplasma species +
Feline Leukemia Virus
(FLV) or Feline
Immunodeficiency
Virus(FIV).
 Acute Extravascular
Hemolytic Anemia.
 lethargy, anorexia, and
fever, with splenomegaly
and icterus.

16. Diagnosis :
1. PCR
2. Blood Smear staining-
Romanowysky
Dog with Mycoplasma haemocanis infection
Treatment
 Doxycycline (10
mg/kg/day, PO, for a
minimum of 2 wk; with
water in cats)
 Enrofloxacin (5 mg/kg/day,
PO) is a suitable alternative
to doxycycline.
 Treatment of PCR-positive,
healthy cats is currently not
recommended
 Immunosuppressive
dosages of glucocorticoids
to suppress immune-
mediated RBC injury.

17. Hepatozoonosis
 Hepatozoon canis - transmitted by the brown dog
tick, Rhipicephalus sanguineus.
 North America - H americanum - transmitted by
the Gulf Coast tick, Amblyomma maculatum -
American Canine Hepatozoonosis (ACH).
 Eating paratenic (transport;Ticks) hosts that contain
cystozoites - enter the vertebrate host via the gut.
 Immunocompetent dogs appear to tolerate infection
with H canis very well.

18. Clinical presentation
 Depression
 Muscle atrophy
 Bloody diarrhea
 Fluctuating Fever 102.7°–106°F
 Mucopurulent ocular discharge
 Severe hyperesthesia or pain over the paraspinal
region is a common finding on physical
examination
Dogs maintain a normal appetite if food is placed directly in front of them,
but they often will not move to eat, apparently owing to intense pain!

19. Diagnosis Treatment
 Neutrophilic leukocytosis,
(WBC = 20,000–200,000
cells/μL).
 A mild to moderate
normocytic, normochromic,
nonregenerative anemia
 Platelets - normal to high
 Mildly increased ALP
 Radiographs, periosteal
reactions - resemble those of
hypertrophic osteoarthropathy
 PCR
 No known therapeutic
regimen completely clears the
body of the organism.
 TCP = Trimethoprim-
sulfadiazine (15 mg/kg, PO,
bid) + Clindamycin (10
mg/kg, PO, tid), +
Pyrimethamine (0.25
mg/kg/day, PO)
 Decoquinate may prevent
clinical relapses - 10–20
mg/kg, PO, bid continuously
for 2 yr.
 Imidocarb dipropionate twice
monthly, @ 5–6 mg/kg, SC
 Avoid corticosteroids

20. Trypanosomiasis
 CHAGAS' DISEASE - Trypanosoma cruzi
infection more common in dogs.
 American trypanosomiasis – zoonotic – vector
borne disease - transmitted by Triatomine
(nocturnal and hematophagous) ‘kissing’ bugs
and caused by T cruzi.
 >100 mammalian species (except in Avians!)
 Dogs (insectivorous by nature) serving as a major
domestic reservoir.

21. Trypanosomiasis
Pathology
 T cruzi maturation occurs in the bloodstreams and
anal odoriferous glands of dogs, and infective
trypomastigotes can be shed in feces or urine and
ingested.
1. Acute - lymphadenopathy, anorexia, pyrexia,
vomiting, diarrhea, and hepatomegaly or
splenomegaly and seizures.
2. Chronic phases
a) Latent - generalized weakness or sudden death.
b) Symptomatic – Right side-CHF – myocarditis +
arrhythmias + DCM – Death.

22. Trypanosomiasis
Diagnosis Treatment
Routine Peripheral Blood
Smear:
 Giemsa stain, T cruzi is an
extracellular, C-shaped
protozoan with a single
flagellum.
 PCR
 T. cruzi - Benznidazole is the
drug of choice @ 5–10
mg/kg/day, PO, for 2 months.
 Diminazene aceturate @
dose of 3.5 mg/kg in T.
congolense infection; 7 mg/kg
in T. brucei brucei andT. evansi
(Aquinos, 2007)
 Quinpyramine sulphate and
Allopurinol have also been
tried with a moderate success
rate – literature insufficient.

23. THANK YOU