Ehrlichiosis is a blood disorder caused by blood cell parasites called rickettsiae. Of the four different rickettsiae that can cause the disease, Ehrlichia canis is the most common.
Dogs are infected when they are bitten by ticks carrying the rickettsiae or when they receive transfusions of blood contaminated with the rickettsiae. Signs of ehrlichiosis develop within 8 to 20 days.
The acute or early phase of the disease lasts 4 to 6 weeks and is characterized by such signs as weight loss, fever, depression, discharge from the eyes and nose, respiratory problems, and enlarged lymph nodes. Many dogs recover after this stage of the disease. In other dogs, the infection becomes subclinical, lasting months or years. Stress or treatment with various drugs in these dogs may result in severe clinical signs of ehrlichiosis.
Dogs with a mild form of ehrlichiosis may become chronically infected and show depression, weight loss, hemorrhage, fever, and various other organ problems.
Ehrlichiosis is diagnosed by blood tests. The disease is prevented by controlling tick infestation of the dog.
Important Points in Treatment
1. Ehrlichiosis usually can be treated, regardless of the stage of infection. However, the earlier the disease is detected, the more rapid is recovery. Chronically infected dogs may require treatment for several months. Dogs with severe anemia or hemorrhage may require blood transfusions.
2. Repeated blood tests are required during the treatment period.