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Tucson, AZ 85711

Ehrlichia Canis – Tick Fever in Dogs

Encanto Pet Clinic continues to offer $10 off Heartworm/Tick Disease screening through the month of May! Just mention this post to the staff at Encanto Pet Clinic.

Treating Ehrlichia canisWhen Matthew Rentschlar adopted Sadie, a 3-year-old pit bull/lab mix, from Pima Animal Care Center (PACC), he was told she had tested positive and treated for Ehrlichia canis. Rentschlar brought Sadie to Encanto Pet Clinic for her new pet examination, and discovered she would need a longer treatment with antibiotics to clear her of the infection.

Ehrlichia canis, also known as tick fever, is a rickettsia; a small parasite that lives in the red blood cell of the infected animal. It is spread by the brown dog tick (Rhipicephalus sanguineus). The rod-shaped organisms reside in the salivary glands of infected ticks and they are transferred through the tick’s saliva to dogs while the tick is feeding.

Ehrlichia was first described in Algeria in 1935, and in 1965 a group of military dogs stationed in Vietnam died from what was later determined as Ehrlichia canis. The spread and reporting of the disease has increased over the last decade, and today it has been reported in all 50 states and 5 continents.

Once bitten by an infected tick, E. canis develop inside macrophages, a type of white blood cells. The rickettsia attack the spleen, but the lymph nodes, liver and bone marrow may also be affected. Platelets are destroyed as a result of the infection, and the organs can become enlarged. Symptoms include anemia, fever, joint pain and shortness of breath. Because the organisms live inside the cells, antibiotics may not be able to reach them.

encanto pet clinic april 2015 2Sometimes, dogs exhibit little or no signs of the infection; Ehrlichia are able to live inside a dog’s spleen for months. A small number of dogs can fight off the infection, but the majority progress to the chronic phase of the infection. Affected patients may have weight loss, anemia, bone marrow loss, edema, fever or signs of neurological damage (such as loss of coordination, change in temperament, or repetitive licking behaviors). Lymphocytes will increase and will have an abnormal appearance (and can sometimes be misidentified as leukemia). Changes in protein levels are apparent, and arthritis or kidney problems may develop. At this stage, Ehrlichia canis is difficult to manage with treatment. Death is caused by hemorrhage, autoimmune disease or secondary infections.


IMAG0005-2If your veterinarian at Encanto Pet Clinic suspects Ehrlichia canis, he or she will use an ELISA test that detects the dog’s antibodies to Ehrlichia, and a complete blood count (CBC) and a chemistry panel to determine the effect the organism is having on the body. However, antibodies may not be detected during the early stages of the infection, or he may be too ill to produce enough antibodies. These tests will tell the veterinarian that the dog has been exposed – not that he is presently infected. A PCR diagnostic test looks for the presence of the organism itself. Unfortunately, it does not distinguish between live and dead organisms. For this reason, it is generally recommended to perform the PCR along with one of the antibody tests to make a diagnosis.

Sometimes, the organism can be seen inside cells on a blood smear. To find them, a small drop of blood is spread over a microscope slide, stained and examined under the microscope. The organism can only be found in the bloodstream for a few days during the acute phase of the disease. So this method of diagnosis could miss some cases of the disease.


Ehrlichia canis is treated with antibiotics, usually doxycycline or tetracycline, over a three to four-week period. Dogs may show signs of improvement within a few days, but don’t stop the treatment! It is important to complete the course of antibiotics.
A dog can become re-infected, so once recovered, a complete blood count (CBC) is necessary to monitor health. Long-term treatment of antibiotics could prevent re-infection, and tick prevention is important. Rentschlar reports that Sadie is doing well and very happy in her new home. He is dedicated to keeping her free of Ehrlichia canis by following up with testing and preventatives.

Ticks can carry more than one problem!!

One tick can transmit more than one disease, so your dog can be infected with a number of illnesses through one bite. Here are some examples of tick borne illnesses:

  • Canine Anaplasmosis
  • Rocky Mountain Spotted Fever
  • Canine Babesiosis
  • Canine Bartonellosis
  • Canine Hepatozoonosis
  • Lyme disease

The best treatment is prevention! Schedule an appointment for testing and/or preventative today.