Outbreak of canine monocytic ehrlichiosis in Saudi Arabia.
BACKGROUND
Canine monocytic ehrlichiosis (CME) is a widespread tickborne infection of canids caused by Ehrlichia canis, a gram-negative obligatory intracellular bacteria belonging to the family Anaplasmataceae. CME is reported to have worldwide distribution, but its presence in a region requires the presence of the vector, the brown dog tick Rhipicephalus sanguineus.


OBJECTIVE
This purpose of this report was to describe an outbreak of CME in a colony of dogs resident in the eastern region of Saudi Arabia.


METHODS
History, presenting clinical signs, and the results of a CBC, biochemical panel, and serology (using a commercial test for E canis antibodies) were evaluated in 9 male Labrador Retrievers between October and December 2006.


RESULTS
The majority of dogs presented with severe lethargy (7/9) and acute anorexia (5/9), and had fever (7/9) and generalized lymphadenopathy (7/9). The most common laboratory abnormalities were anemia (8/9), leukopenia (7/9), and hypoalbuminemia (6/9). Thrombocytopenia was found in only 2 dogs, 1 of which had increased bleeding tendency. Ehrlichia morulae were identified in blood films from 4/9 dogs and serologic test results were positive in 7/9 dogs. Confirmation of Ehrlichia sp infection was obtained in 1 dog by using a genus-specific real-time PCR assay. Four dogs had tick infestation; the ticks on 1 dog were identified as R sanguineus. All of the dogs had a rapid clinical response to doxycycline hyclate.


CONCLUSIONS
This report, to our knowledge, is the first to describe the presence of a pathogenic Ehrlichia organism affecting dogs in Saudi Arabia. Additional molecular studies are necessary to confirm E canis infection, and to identify the strain of the organism.
Sacchini
Federicl
F
IDEXX Laboratories Ltd., Wetherby, West Yorkshire, UK. federico-sacchini@idexx.com
Cessford
Rory J
RJ
Robinson
Bede M
BM
D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D004196:Disease Outbreaks / Q000662:veterinary*; D004283:Dog Diseases / Q000453:epidemiology*; D004285:Dogs; D004318:Doxycycline / Q000627:therapeutic use; D016873:Ehrlichiosis / Q000188:drug therapy / Q000453:epidemiology / Q000662:veterinary*; D008297:Male; D012529:Saudi Arabia / Q000453:epidemiology
D000900:Anti-Bacterial Agents; D004318:Doxycycline