Canis ISSN: 2398-2942

Granulocytic anaplasmosis

Synonym(s): Anaplasmosis

Contributor(s): Leah Cohn, Severine Tasker

Introduction

  • CauseAnaplasma phagocytophilum, tick-borne infection.
  • Signs: pyrexia, lethargy, anorexia and musculoskeletal pain in acute infections.
  • Diagnosis: detection of morulae on blood smear, serology, PCR.
  • Treatment: doxycycline.
  • Prognosis: Usually mild disease - no deaths due to canine granulocytic anaplasmosis have yet been reported.
  • Anaplasma phagocytophilum infects a wide range of mammals but clinical illness documented in dogs, horse, cattle, sheep, goats, llamas, cats and humans.
  • Many small mammals and deer are implicated as natural reservoirs of A. phagocytophilum - however different prevalences are reported in humans, dogs and horses, and potential reservoir host species from the same area, suggesting that variant A. phagocytophilum strains may exist in different host species.
Print off the owner factsheet Anaplasma phagocytophilum infection to give to your client.

Pathogenesis

Etiology

Predisposing factors

General

Specific

  • Infected Ixodes spp ticks.

Pathophysiology

  • Joint vectors with Borrelia burgdorferi (transmitted by many of the same tick vectors) may worsen the severity of disease.

Timecourse

  • Ixodes spp ticks need 24-48 hours of attachment to the dog to transmit A. phagocytophiluminfection.
  • Disease incubation after tick bite is 1-2 weeks.
  • Dog can maintain infection for months, often without concurrent illness.

Epidemiology

  • Transmitted by bites from Ixodes spp tick vectors, especially:
    • Ixodes pacificus Ixodes pacificus on western coast of United States (same spp that transmit Lyme disease Borreliosis in North America).
    • Ixodes scapularis Ixodes scapularis in the north-eastern and southern coastal regions of the United States (same spp that transmit Lyme disease in North America).
    • Ixodes ricinus Ixodes ricinus throughout Europe (same spp that transmits Lyme disease and the flavivirus that causes tick borne encephalitis (TBE) in Europe) and eastern Russia.
    • Ixodes persulcatus across sections of Russia and northern Asia.
  • Wildlife such as rodents, and other small animal act as the reservoir hosts, with transmission to domestic animals and man as a result of tick bites.
  • Wild ruminants such as deer may also act as reservoirs for selected strains of Anaplasma spp.
  • It has been suggested that the infection can be introduced into disease-free areas by migrating birds.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Carrade D D, Foley J E, Borjesson D L & Sykes J E (2009) Canine Granulocytic Anaplasmosis: A Review. JVIM 23, 1129-1141 PubMed.
  • Stuen S (2007) Anaplasma Phagocytophilum - the most widespread tick-borne infection in animals in Europe. Vet Res Commun 31 (Suppl 1), 79-84 PubMed.


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