As a result of the infection the lymph nodes, liver and spleen are often enlarged. Anemia , fever, depression, lethargy, loss of appetite, shortness of breath, joint pain and stiffness, and bruises are often seen. In the subclinical phase the animal may show only slight anemia. During this phase the dog either eliminates the Ehrlichia from the body or the infection may progress to the chronic phase. The chronic phase generally develops 1-4 months after the tick bite and can be either mild or severe.
Blood tests show that one or all of the different blood cell types are decreased.
One cell type, the lymphocyte may increase and be abnormal in appearance. This can sometimes be confused with certain types of leukemia. If a dog becomes chronically infected, the disease can keep coming back, especially during periods of stress. Changes in the protein levels in the blood are common. The antibodies may not be detected in the early phase of the disease since it takes some time for the body to make them.