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Old April 26th, 2008, 06:32 PM
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Dr Lee Dr Lee is offline
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Tick Fever in dogs and cats - Answered by Dr. Lee

Just wanted to make a note on Tick Fever (Ehrlichia) and other tick borne diseases. During Spring we will notice that the flowers bloom, romance flourish and ticks comes out to play. Not only do these nasty little guys cause painful bites, suck blood and are absolutely gross but they can also carry disease.

This last week I diagnosed three Ehrlichial cases and two were given a guarded prognosis but are currently doing fine. Rickettsial diseases are a group of gram negative bacteria that use various arthropods such as lice, ticks and fleas to move from host to host. The must live inside a living cell. Rickettsial diseases make up a large portion of the tick borne diseases. Some examples of rickettsial diseases include: Ehrlichia (tick fever), Rocky Mountain Spotted fever (rickettsia ricketssii), and Anaplasmosis to name a few. Lyme disease is not a rickettsial disease but is also tick borne. It is a spirochete. Another tick borne disease which is not rickettsial is Babsesia.

Tick borne diseases often create vague signs and can often be missed or passed up as a diagnosis. (especially if the pet has traveled to an ehrlichia area for example but lives in a non-tick area for his or her veterinary care). Many tick borne diseases prefer certain tick types. Both the diseases and ticks have demographic 'hot zones'. If your pets live in or have ever traveled to tick areas, asking your veterinarian about testing may be beneficial.

It also brings up the idea of prevention. There are many tick products out on the market. I still am a big Frontline Plus fan. It is safe (it can be eaten without harm). It is waterproof and sunlight proof (many of the others remain topical and as such are diluted with bathing and degrated by UV light). It was also tested with repeated baths with soap lasting 15minutes and still have 100% efficacy at 30 days. Most importantly though, the manufacturer states that not one pet has been diagnosed with a tick borne disease while on this medication. I also like Revolution and Advantix. There is a new product called Promeris but there seems to be side effects and a horrid smell which have not made it be the 'champion' of tick medications as it was thought to have been. For dogs that are considered to have minimal exposure, many over the counter tick collars can work great.

About half of the patients that I diagnose with tick borne disease have owners who can say something like, "well that is impossible, because I have NEVER seen a tick." Many times I think the dog has found the tick and gotten rid of it however the disease may have already been transmitted. It only takes one tick sometimes. In Arizona, one of our labs have diagnosed over 20,000 cases in a five year period.

How are these diseases tested for? Specific blood tests looking for each of them. Traditionally there have been antibody titers which look for patient response to the disease. These are great because they are highly sensitive. Their drawback is that they have a difficult time differentiating between exposure, previous infection and active current infection. There is new technology that looks for the DNA of the tick borne disease (our new lab does a 'fast panel' which looks at 11 different tick borne diseases at once). The great advantage to this is that if the test is positive, there is no question that infection is present unlike the antibody test. Unfortunately the technology is still a little new and we do not know quite how sensitive it is. Currently the laboratory specialist are recommending running both. Hopefully in the future there will be better data on this.

As far as clinical signs, they can vary from disease to disease. Most have aspects of lethargy, joint stiffness or shifting lameness, and fever. Since ehrlichia is in my neck of the woods, our website has information on it at http://www.aachospitals.com/diseaseinfo/ehrlichia.html

Hopefully no one on this forum will ever run into a tick borne disease but thought I should make mention of it.
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Christopher A. Lee, D.V.M., C.V.L.S.
Promoting surgical options and pet comfort through the use of lasers.
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