Ehrlichia canis is an obligate intracellular bacterium that acts as the causative agent of ehrlichiosis, a disease most commonly affecting canine species.

[8][10] The cell walls of this organism lack peptidoglycans and lipopolysaccharides typically present in at least small amounts in most other Gram-negative bacteria, which is believed to contribute to its ability to resist the immune response of the host.

[10] The cells of E. canis lack complex internal structures, which allow the synthesis of sugars and it, in turn, uses amino acids as its source of energy.

[11] Animals infected with E. canis may experience a combination of signs, including fever, lethargy, weight loss, lymphadenopathy, edema of the appendages, discharge from nose and eyes, and seizures.

If caught before the clinical stage, E. canis is almost completely curable, but prolonged presence of the bacteria leads to hemorrhaging, which typically results in the death of the patient.