Ehrlichia – Tick Fever
by Susanne Stack, DVM
Ehrlichia (Ehrlichiosis), also referred to as Tick Fever, is a worldwide canine blood parasite that in the US is found mostly in Arizona. The disease is transmitted by ticks but should not be confused with the other tick-borne illnesses such as Lyme disease or Rocky Mountain Spotted Fever.
It takes only ONE infected tick to transmit Ehrlichia and the dog may be infected for up to 5 years before showing any clinical signs. Therefore, infected dogs are not necessarily covered with ticks at the time of illness, nor do ALL ticks carry the disease.
Ehrlichia destroys red blood cells and platelets, making dogs anemic, and if the platelet count drops low enough can prevent blood clotting. Signs of Ehrlichia range from vague symptoms such as lethargy, anorexia or fever to classic presentations with nosebleeds and petecchial hemorrhages (little purple or red spots under the skin). Rarer cases have ocular, neurological or joint involvement.
The diagnosis is made with a simple blood test. Whether the owner has seen ticks on the dog should not influence the request for the blood work.
Treatment for Ehrlichia is with an antibiotic called doxycycline, which is simple and inexpensive. AAGI recommends that if your dog tests positive you administer the doxycycline for a period of 2 months to ensure complete eradication. Most dogs recover without incident. In rare cases other complications can arise.
Ehrlichia is such a common diagnosis in Arizona that AAGI recommends any greyhound with an unexplained illness be tested for Ehrlichia by your veterinarian.
We occasionally see dogs that will test positive for exposure to Babesiosis or other tick related diseases but it is rare to see them develop any symptoms.
For ideas on flea & tick prevention please see related article.