There's a New Bad Boy in Town- Ehrlichiosis
by Dr. Linda Wolf, D.V.M.

You would think Minnesota pet owners would have enough to worry about with heartworm, lyme disease, west nile virus to name a few. Well, as a pet owner you need to become aware and learn more about a disease that can be a deadly killer and is claiming lives of dogs (extremely rare in cats) in all 50 states and has definitely found its way to Minnesota. That disease is Ehrlichiosis. Ehrlichia is a tick-borne rickettsial disease that is divided into several groups- the main ones being Ehrlichia canis, Ehrlichia equi and Ehrlichia risticii. Rickettsias parasitize white blood cells and inhibit the basic function of the bone marrow (making new cells to replace the old). Once an animal or human (yes- people can contract Ehrlichia also- the first human case was reported in the U.S. in 1986), has been infected with ehrlichia, white cells die off faster than the bone marrow can replace them. So how do our animals get this disease? The pathophysiology is very similar to Lyme's disease. A tick transmits the disease through their saliva. There is a 1-3 week incubation period, which is followed by three stages of the disease: acute, sub clinical and chronic. Because the disease is multisystemic (affects many systems of the body) the signs of the disease vary greatly. In most cases, the early signs are very subtle and in almost all cases the signs mimic those caused by other diseases. In the acute phase the signs are often very similar to viral infections. The animal may run a fever, lose their appetite, act depressed, show abdominal or eye pain, or have breathing problems. Very often the animal wants to be left alone. But due to the fact that the disease can manifest itself in many body systems, almost any physical sign that is not normal can signal this disease. It is extremely important to catch the disease at the early stages and treat before the disease goes into the chronic phase. Although blood work can show abnormalities, the most clinically useful and reliable method at this time to diagnose Ehrlichia is to do an IFA (indirect fluorescent antibody test), which detects the presence of antibodies in the blood. However, IFA could be negative during the very early phase of the disease even when there are severe clinical signs evident. Another test called a PCR test (polymerase chain reaction test) offers the most specific and sensitive detection method but is not commercially available. This is a DNA-based test that shows the actual presence of ehrlichia in the blood. Hopefully, it will become more available in the future. One of the main problems of this disease is that many veterinarians are not familiar with ehrlichiosis. They are not aware of the magnitude of the problem. And because of the way the clinical signs of Ehrlichia can mimic so many other diseases, it often gets misdiagnosed and treated as something else. So far it sounds like all gloom and doom. But there is good news. Very good results in treatment can be obtained with appropriate antibiotics if done early and aggressively. And of course, the best way to deal with this disease is through prevention/avoidance by controlling the tick infestation on your animals by tick control products, routine checking and removal of ticks, and avoiding high tick infested areas. Also: remember, this disease is a zoonotic disease meaning humans are susceptible to it also. So why does this disease have such significance for me. Because my own dog Meghan contracted Ehrlichia equii last fall. Since she didn't present with any of the historical clinical signs (she actually had diarrhea and vomiting with abdominal pain), it would have been very easy to assume it was something else like inflammatory bowel disease or pancreatitis. But I wasn't comfortable with that diagnosis and decided to run a full tick titer panel. The IFA results came back positive for E. equii and I started aggressive drug therapy immediately. Because of that, my Meghan is still with me. Others have not been as fortunate. I hope a vaccine will be developed to protect our loved companions from this deadly disease, but until that time make sure your veterinarian is informed about this disease, make sure theyi are aware of the broad range of clinical signs it can present with, and be proactive and keep your pets as safe as is possible. Side note: a good lay article that expands on this can be found at How Ehrlichia Affects Your Dog