What is Ehrlichiosis?
Ehrlichiosis is a tick-borne infectious disease. In dogs, disease is caused by the bacteria Ehrlichia canis. The organism affects cells of the immune system in dogs, cats, and people. E. canis is transmitted by the brown dog tick and is found worldwide. Other tick species have also been shown to transmit the disease as well.
This pathogen has been found in all 48 contiguous United States, but is more prevalent in the south.
Ehrlichia ewingii is similar, but is spread by the Lonestar tick and is found more commonly in the southeast and midwest United States.
What are the symptoms of Ehrlichiosis?
The organism lives inside the white blood cells of the dog. It can remain there for months without causing clinical disease symptoms in the dog. Dogs with a healthy immune response will make antibodies against the organism and kill it, resulting in no clinical disease.
The disease seems to be particularly severe in German Shepherds and Doberman Pinschers. It first gained attention when military dogs returning from Vietnam during the 1970's were found to be infected. Symptoms may include fever, swollen lymph nodes, coughing, respiratory distress, weight loss, bleeding disorders, bruising, swollen limbs, enlarged spleen, eye inflammation, lameness, anemia, and wobbly gait. Severe disease can lead to uncontrollable hemorrhage and death.
How is Ehrlichiosis diagnosed?
Screening tests such as the 4DX and Accuplex may detect antibodies to the Ehrlichia organism. However, this does not always correlate with clinical infection. Secondary testing with PCR or ELISA will determine if the organism is present and which species of organism is present. If the PCR is negative, no treatment is needed, unless the dog is clearly symptomatic.
A CBC (complete blood count) may show anemia (low red blood cell count) or thrombocytopenia (low platelet count). A chemistry screen may reveal high levels of protein globulin signifying an inflammatory response. Urinalysis may show loss of protein in the urine if the kidneys are being affected by the disease.
How is Ehrlichiosis treated?
Treatment includes the use of doxycycline, an antibiotic, once or twice daily for three to four weeks. Improvement should be seen within 24 to 48 hours. Doxycycline commonly causes nausea and vomiting. Doxycycline should not be given with dairy products, as calcium will bind the drug, rendering it useless. Dogs with severe anemia may require a blood transfusion.
How is Ehrlichiosis prevented?
No vaccines are available for this disease. Keeping ticks off your dog is your best defense. Please do this as naturally as possible. Your dog's healthy immune system can keep this disease from every becoming clinically manifested.
Prevention is accomplished by controlling ticks in the environment and on the dog. Dogs in areas infested by ticks should be limited from walking off-trail, in high grass, and in leaf-littered wooded areas.