Canine Ehrlichiosis is infectious disease of dogs.

1. Department of Veterinary clinical Medicine,ethics and Jurisprudence
College of Veterinary and Animal Sciences,Bikaner
(Rajasthan University of Veterinary and Animal Sciences,Bikaner)
A seminar On
Canine Monocytotropic
Ehrlichiosis
PRESENTED BY
Dr.RAM CHANDER Tiwari
M.V.Sc. Scholar

2. OUTLINE
 Introduction
 Etiology
 Epidemiology
 Pathogenesis
 Clinical findings
 Clinical pathology
 Diagnosis
 Treatment
 Prevention and Control

3. INTRODUCTION
 Synonyms –
- Tracker dog disease
- Canine monocytic ehrlichiosis
- Tropical canine thrombocytopenia
- Canine haemorragic fever
- Canine rickettsiosis
 The disease was initially identified by Donatien and
Lestoquard in Algeria in 1935.
(Donatien and Lestoquard,
1937)

4.  In 1970s a large number of American military dogs,
died during the Vietnam War from this rickettsial
disease.
(Groves et al.,
1975)
 In India, E.canis was first reported in Madras by
Mudaliar 1944.
 Infection occurs mainly during the warm season
when the vector tick is active.

5. ETIOLOGY
 A number of Ehrlichia spp. infections have been
reported in dogs including
-E. canis
-E. chaffeensis
-E. ewingii
(Qurollo et al, 2013)
 Ehrlichiosis is a rickettsial disease of dogs caused
by Ehrlichia spp., principally transmitted by nymphs
and adults of Rhipicephalus sanguineus.
(Moraes-Filho et al.,
2015)

6. ORGANISM MORPHOLOGY
 Coccobacilli
-Small, pleomorphic shape
-Gram negative
-Obligate intracellular (Rikihisa et al., 2001)
 Three intracytoplasmic forms
-Initial body
-Elementary body
-Morulae
 It consists of a single circular chromosome
containing 1,315,030 nucleotides.
(Mavromatis et al.,

7. Ehrlichia canis morulae within the
cytoplasm of a monocyte as seen
in blood smears (photographed at × 1000).
The brown dog tick, Rhipicephalus . A
male (left) and engorged female
(right).

8. Species Name of
disease
Common
natural
host
Cells
mostly
infected
Primary
vector
Distribution
E. canis Canine
monocytic
ehrlichiosis
(CME)
Canids Primarily
monocytes
and
lymphocyte
s
Rhipicephalus
sanguineus,
Dermacentor
variabilis
Worldwide,
tropical,
subtropical,
& temperate
E.
chaffeensi
s
Human
monocytic
ehrlichiosis
(HME)
Humans,
dogs,
goats,
lemurs
in captivity
Monocytes,
macrophag
es
Amblyomma
americanum,
Dermacentor
variabilis
USA,
Europe,
Africa, South
and Central
America,
E. ewingi Canine
granulocyti
c
ehrlichiosis,
human
granulocytic
ehrlichiosis
Dogs,
humans
Primarily
neutrophils
and
eosinophils
Amblyomma
americanum,
Otobius
megnini
USA, Africa,
Korea
E.
ruminantiu
Heartwater
disease
Ruminants Endothelial
cells
Amblyomma
spp.
Africa,
Caribbean

9. EPIDEMIOLOGY
 Worldwide distribution.
 Free of E. canis infection - Australia.
 Vertebrate hosts - family Canidae.
 Arthropod vector -brown dog tick
(Rhipicephalus sanguineus)
-American dog tick
(Dermacentor variabilis )
(Dumler et al.,
2001)

10.  German shepherd dog -most susceptible breed,
higher morbidity and mortality compared to other
breeds . (Nelson and Couto,
2003)
 Ehrlichia canis is transmitted transstadially by
Rhipicephalus sanguineus ticks.
(Bremer et al.,
2005)
 Also transmitted by blood transfusion.

11. TRANSMISSION
 Rhipicephalus sanguineus is the primary vector of
E. canis, which is the cause of monocytic
ehrlichiosis.
(Groves et al.,
1975)
 Rhipicephalus sanguineus is the vector of tick-
borne pathogens affecting dogs and occasionally
humans.
(Dantas-Torres,
2010)
 E. canis is currently not considered an organism

12. .
Life cycle of Ehrlichia canis. The organism is transmitted only transstadially
(from larva to nymph to adult) within the tick.

13. PATHOGENESIS
 The incubation period is followed by three
consecutive stages:
-Acute phase
-Subclinical phase
-Chronic phase
(Skotarczak,
2003).

14. Variable
Reductio
n in Hb,
RBC,WBC
Splenomegaly,
Lymphedinomeg
aly
Hyper-
globulinem
ia
Resolved
fever,clinically
healthy,Persistent
thrombocytopenia
Hemorrhagic
Tendencies
Fever, Anorexia, Meningitis,
Mentaldepression,Hypoalbumine
mia
Retinal
detachment
Pancytopenia
Vector/Blood borne
Infection
Mononuclear cell
Mononuclear phagocytosis
(Liver,Spleen,Lymph nodes)
Lymphocytic perivascular cuff
(Lung,Kidney,Meninges,Eye)
Altered Cell mediated immunity
Thrombocytopenia
Lymphocyte & Plasma
cell proliferation
Recoverd
Hyperviscos
ity
ACUTE
2-4weeks
SUB-CLINICAL
months-year
CHRONIC
months8-20 days

15. CLINICAL FINDINGS
 ACUTE PHASE (develop 1-3 weeks after the bite)
- High Fever
- Depression
- Lethargy
- Anorexia
- Lymphadenomegaly
- Splenomegaly and
- Hemorrhagic Tendencies
- Dermal petechiae
- Ecchymoses
- Epistaxis.

16. `
 Ocular Signs-
-Hyphema
- Uveitis
- Scleral bleeding
- Retinal detachment. (Komnenou et al.,
2007)
 Neuromuscular Signs-(CNS symptom)
-Seizures
-Cerebellar Dysfunction
-Anisocoria
-Hyperesthesia

17. Ventral abdominal skin petechiation due
to thrombocytopenia in a bitch
Mucosal petechiae

18. Epistaxis in a dog due to Ehrlichia canis
infection.

19. Ocular Signs
Hyphema in a dog Scleral bleeding in a
dog

20. SUBCLINICAL PHASE
 During the subclinical phase no clinical signs are
evident. (Waner et al., 2011)
CHRONIC PHASE (develops 1-4 months after bite )
 Symptoms similar to acute phase(with great
severity)
-Pale mucous membrane
-Weakness
-Bleeding and
-Significant weight loss. (Harrus et al.,2011)

21. CLINICAL PATHOLOGY-
Acute stage
 Significant thrombocytopenia with platelet counts
ranging from 20,000 to 52,000/μL.
 Mild anemia and mildly reduced white blood cell
counts.
Sub clinical stage
 Mild thrombocytopenia with platelet counts ranging
as low as 140,000/μL.
(Harrus et al.,2011; Waner et
al.,2011)

22.  Leukocyte and erythrocyte counts may also be
reduced. (Waner et al.,2011)
Chronic stage
 Marked pancytopenia due to bone marrow
hypoplasia is a hallmark of the chronic severe form.
(Harrus et al.,
2011)
 Marked anemia and leukopenia.

23.  The clinicopathological findings are
-Anemia
-Thrombocytopenia
-Pancytopenia
-Leucopenia
-Hyper-globulinemia and
-Hypo-albuminemia (Harrus and Waner,
2011; Harrus et al.,2012; Vinasco et al., 2007).

24. DIAGNOSIS
 History-Tick history
 Clinical signs
 Hematologic abnormalities
 Rapid Immunochromatographic kit test
-In a positive case both
visible
T and C band will appear indicate the presence
of
Ehrlichia Canis antibodies in the sample.
CT

25.  Buffy coat smears- For demonstration of
morulae in monocytes.
-Morulae can also be seen in bone marrow cells
and cerebrospinal fluid.
 PCR - PCR has been shown to be a sensitive
method for detecting acute E. canis infection in
dogs.
(Harrus et al., 2004; Mylonakis et al.,
2004)
 IFA-(‘gold standard test’) An indirect fluorescent
antibody (IFA) test is usually performed to detect
antibodies in dogs infected by Ehrlichia canis.
(McBride et al., 2003)

26.  ELISA-Enzyme-linked immunosorbent assays
(ELISA) have been useful in the diagnosis E.canis.
(Harrus et al.,
2002)
 Organism Cultivation-this method is expensive and
not routinely available
 USG- Multiorgan dysfunction with liver and spleen
involvement is common in clinical cases of canine
monocytic ehrlichiosis.
(Ganguly and
Mukhopadhayay, 2008)

27. TREATMENT
 FIRST: Properly Remove Tick-(Manualy/medicinal)
Fipronil
Methopren 1-Fipro-fort plus (Savavet)-
9.8%w/v 11.8%w/v
2-Fixotic advance(Vetoquinol)-0.25%w/v
0.22%w/v

28.  Antimicrobial therapy-
IV , Intravenously; PO , by mouth; SC , subcutaneously.
Drug Dose (mg/kg) Route
Preferred
(Alternative)
Interval
(hours)
Duration
(days)
Doxycycline 10
5
PO
PO
24
12
21-28
21-28
Minocycline 10 PO 12 21-28
Tetracycline 22 PO 8 21-28
Oxytetracycline 7.5-10 IV 8 21-28
Chloramphenic
ol
25-50 PO (IV/SC) 8 21-28

29.  Imidocarb dipropionate (2 doses of 5mg/kg, IM,
repeat after 2-3 weeks).
 Imidocarb an antiprotozoal drug,has been
successful in treating resistant E.canis infection.
 This drug persist in the tissues for up to 1 month
following one dose.
 When imidocarb was given as a single IM injection,
83.9% of dogs recovered. (Craig E.Greene,2005)
 Drug of choice – Doxycycline (5-10 mg/kg,po)
(Harrus et al.,2004)

30.  Supportive therapy
 Fluid therapy-for curing dehydration in infected dog.
 Blood transfusions-if the dog is severely anemic.
(platelet-rich plasma)
 Glucocorticoids-(1 to 2 mg/kg prednisolone, PO)
 Livertonic medicine-effective hepatostimulante

31.  Monitoring of Treatment
 Clinical signs improve within 48 hours.
 The platelet count should remain normal at 4 and 8
weeks.
 Hyperglobulinemia should gradually resolve over 6
to 9 months.
 PCR should be negative at 2 weeks after
successful treatment.

32. PREVENTION
 A vaccine is not currently available.
 Minimizing tick exposure.
 Use prophylactic drug Doxycycline (3mg/kg PO
q24h) in highly endemic areas.
 All newly introduced dog into a kennel should be
serotested, treated for ticks.
 Whole blood should be tested before transfusion.

33. REFERENCES
 Abeygunawardena IS, Kakoma I, Smith RD. 1990. Pathophysiology of canine ehrlichiosis,
pp 79-92. In Williams JC, Kakoma I (eds): Ehrlichiosis. Kluwer, Dordrecht, The
Netherlands.
 Anderson BE, Greene CE, Jones DC, et al. 1992. Ehrlichia ewingii sp. nov., the etiologic
agent of canine granulocytic ehrlichiosis. Int J Syst Bacteriol 42:299-302.
 Anderson BE, Dawson JE, Jones DC, et al. 1991. Ehrlichia chaffeensis, a new species
associated with human ehrlichiosis. J Clin Microbiol 29:2838-2842.
 Anziani OS, Ewing SA, Barker RW. 1990. Experimental transmission of a granulocytic
form of the tribe Ehrlichieae by Dermacentor variabilis and Amblyomma americanum to
dogs. Am J Vet Res51:929-931.
 Harrus, S., Kenny, M., Miara, L., Aisenberg, I., Waner, T., Shaw, S., 2004. Comparison of
simultaneous splenic sample PCR with blood sample PCR for diagnosis and treatment of
experimental Ehrlichia canis infection. Antimicrobial Agents and Chemotherapy 48, 4488–
4490.
 Yu, X.J., McBride, J.W., Walker, D.H., 1999. Genetic diversity of the 28-kilodaltonouter
membrane protein gene in human isolates of Ehrlichia chaffeensis. J. Clin.Microbiol. 37,
1137–1143.

34. Thank You