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Canine ehrlichiosis

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Canine ehrlichiosis

  1. 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. 2. OUTLINE  Introduction  Etiology  Epidemiology  Pathogenesis  Clinical findings  Clinical pathology  Diagnosis  Treatment  Prevention and Control
  3. 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. 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. 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. 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. 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. 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. 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. 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. 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. 12. . Life cycle of Ehrlichia canis. The organism is transmitted only transstadially (from larva to nymph to adult) within the tick.
  13. 13. PATHOGENESIS  The incubation period is followed by three consecutive stages: -Acute phase -Subclinical phase -Chronic phase (Skotarczak, 2003).
  14. 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. 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. 16. `  Ocular Signs- -Hyphema - Uveitis - Scleral bleeding - Retinal detachment. (Komnenou et al., 2007)  Neuromuscular Signs-(CNS symptom) -Seizures -Cerebellar Dysfunction -Anisocoria -Hyperesthesia
  17. 17. Ventral abdominal skin petechiation due to thrombocytopenia in a bitch Mucosal petechiae
  18. 18. Epistaxis in a dog due to Ehrlichia canis infection.
  19. 19. Ocular Signs Hyphema in a dog Scleral bleeding in a dog
  20. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 34. Thank You

Notes de l'éditeur

  • Uvea-iris, ciliary body and choroid,Anisocoria- an unequal size of the eyes pupils,  Hyperesthesia-abnormal increase in sensitivity to stimuli of the sense
  • hypo echogenicity of liver
  • Chloramphenicol has been recommended for puppies younger than 5 month to avoid yellow discoloration of erupting teeth from tetracycline.
  • Immune mediated mechanism-suppression by pred

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