Mycoplasma canis (Haemobartonella canis) is a Gram-negative epierythrocytic parasitic bacterium in dogs. M. canis is transmitted by ticks (and, probably, fleas). The source of infection can be blood transfusion from the infected animal to the healthy one. Mycoplasmas are suspected to be transmitted from bitches to pups, but it has not been proven so far. The acute phase of the disease shows the symptoms of weakness, loss of appetite, weight loss, dyspnoea, fever and pale mucous membranes. The dominant symptom of the disease is haemolytic anaemia. Sick dog shows a decreased appetite, weakness or weight loss. Most often, dogs fall ill after splenectomy (spleen removal), chemotherapy or immunosuppression and when a dog has concomitant bacterial and viral infections.