Susceptibility of dogs to infection with Ehrlichia risticii, causative agent of equine monocytic ehrlichiosis (Potomac horse fever).
Adult dogs 1 to 5 were inoculated IV and/or SC with 3, 5, or 6 ml of a suspension containing 1.2 x 10(4) Ehrlichia risticii-infected cells (derived from primary canine monocyte cell cultures)/ml. Dogs 6 to 8 were inoculated IV and/or SC with 3 or 6 ml of 1.2 x 10(5) organism-free cultured canine monocytes/ml. Ehrlichia risticii was isolated in cultures from inoculated dogs 3, 4, and 5 on postinoculation days (PID) 10 to 16, but not from dogs 6 to 8. Dogs inoculated with E risticii seroconverted between PID 6 and 12. Clinical signs of illness were not observed in these 5 E risticii-inoculated dogs. A pony, inoculated with E risticii isolated from inoculated dog 5, developed clinical signs of equine monocytic ehrlichiosis, including fever, anorexia, depression, and diarrhea, and E risticii was isolated from the pony's blood. This E risticii isolate was then inoculated into susceptible dog 9, and E risticii was repeatedly isolated from dog 9 during PID 6 to 17. Dogs were susceptible to infection with E risticii and may serve as a reservoir of the organism in the field.
Ristic
M
M
Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana 61801.
Dawson
J
J
Holland
C J
CJ
Jenny
A
A
D000818:Animals; D004198:Disease Susceptibility; D004283:Dog Diseases / Q000382:microbiology*; D004285:Dogs; D004536:Ehrlichia / Q000472:pathogenicity; D005260:Female; D006734:Horse Diseases / Q000382:microbiology; D006736:Horses; D008297:Male; D012288:Rickettsiaceae Infections / Q000662:veterinary*