Ehrlichia canis is a rickettsial bacteria, a causative agent of canine ehrlichiosis. Other wild canids (foxes, wolves, jackals) can become infected with Ehrlichia canis. Infection can occur at any age. All breeds are prone to ehrlichiosis. However, German Shepherd dogs and Siberian Huskies are predisposed to develop more severe clinical signs of ehrlichiosis. Co-infections with Anaplasma spp. are common.
Sample: 0,5 ml EDTA-blood, Tick
Modes of transmission
The main, and probably the only, vector for Ehrlichia canis in Europe is the tick Rhipicephalus sanguineus sensu lato, known as the brown dog-tick. Transmission of Ehrlichia canis by R. sanguineus ticks starts within 3 h after tick attachment to the dog.
Following an incubation period of 1 to 3 weeks, three typical phases of the disease occur. The acute phase can last 2 to 4 weeks. The subclinical phase follows the acute stage. Some, but not all infected dogs may advance to a chronic phase.
Clinical signs of ehrlichiosis can vary, and it may include nonspecific signs, like fever, weakness, lethargy, anorexia, lymphadenomegaly, splenomegaly, hepatomegaly, or weight loss. Other signs have also been described, including vomiting, diarrhea, pain, exercise intolerance, edema, cough and/or dyspnea, serous or mucopurulent oculonasal discharge, abortion or neonatal death, and skin ulcers.
Common clinical signs of ehrlichiosis include pale mucous membranes, due to anemia, epistaxis, petechiae, ecchymoses, prolonged bleeding during estrus, hematuria or melena associated with thrombocytopenia, thrombocytopathy, or vasculitis. Ocular signs are also common and can lead to blindness.
Canine ehrlichiosis is usually successfully treated with antibiotics. According to the seriousness determined in the clinic, dogs may need blood transfusions, fluid therapy or antipyretic and analgesic drugs.
The prevention is focused on tick control and using repellents. Re-infections of canine ehrlichiosis are possible, because no persistent or effective immunity develops to defend against re-infection with these pathogens. Currently, no commercial vaccines are available to protect against infections with E. canis.
When dogs are treated in the acute phase, they improve quickly, within 24-48 h, and their prognosis is good when the whole course of therapy is administered.
Canine ehrlichiosis is widespread in the world and endemic in the Mediterranean. Lately, it is spreading north from the Mediterranean.
Foley, J., Drazenovich, N., Leutenegger, C.M., and Chomel, B.B. (2007). Association between polyarthritis and thrombocytopenia and increased prevalence of vectorborne pathogens in Californian dogs. Veterinary Record 160, 159–162.
Sainz, Á., Roura, X., Miró, G., Estrada-Peña, A., Kohn, B., Harrus, S., and Solano-Gallego, L. (2015). Guideline for veterinary practitioners on canine ehrlichiosis and anaplasmosis in Europe. Parasit Vectors 8.