Clinical signs of the disease depend on the degree of anaemia, the stage of infection, and the immune status of the patient. However, neither organisms appear to be primary pathogenic in dogs. Generally the disease is clinically inapparent, unless the dog is splenectomised or immunosuppressed. Such an activation of a latent infection will result in hemolytic anaemia. Acute clinical signs may then include depression, loss of appetite, weight loss, and fever. In severe cases, death can occur. A chronic form of the disease has been reported rarely and may cause slight weakness, an increase in appetite, and pica.
Since ticks are vectors for diverse types of pathogens, more than one agent might be transmitted during the bite of a tick (e.g., causing hemoplasmosis, ehrlichiosis, babesiosis). These co-infections with more than one tick-borne pathogen at a time are quite frequent. Co-infection with Ehrlichia sp. and a subsequent suppression of the dog's immune system can cause clinical acute hemoplasmosis.
- Lappin MR: Bartonella and Haemobartonella in cats and dogs: Current knowledge. In: The Bayer 7th Int. Parasite Symp., 2006, Proc. BSAVA Pre-Congress Symp., Birmingham, pp 17-25
- Messick JB: New perspectives about Hemotrophic mycoplasma (formerly, Haemobartonella and Eperythrozoon species) infections in dogs and cats. Vet Clin North Am Small Anim Pract. 2003, 33, 1453-65