From my vet's newsletter
Ehrlichia is a type of bacteria which infect and live within the white blood cells of their hosts. The hosts can be human, pet, or wild animals. They are spread by tick bites, and because of their location within the cells, not all antibiotics can reach and destroy them.
In the 1980's it became clear that people could be infected by Ehrlichia and research intensified.
Different Ehrlichia species are spread by different types of ticks.
The brown dog tick usually spreads the the canine forms, among other diseases.
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The Lone Star Tick is another carrier of a canine form. This tick has a "star" on the tick's main body. It is important to note, where there are ticks there are many tick-borne diseases: Lyme Disease, Anaplasma, Ehrlichia and probably even some we don't even know about yet. It is not surprising for a patient to be infected with more than one parasite.canine forms, among other diseases.
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There are 3 phases of this illness: acute, subclinical, and chronic.
ACUTE: This is generally a mild phase and occurs 1-3 weeks after the host has been bitten. The ability for your pet to clot after bleeding will be decreased, they may appear to be listless, and be off food. There may be a fever as well but rarely does this phase kill a dog. Most will clear the organism on their own but some will go on the the next phase.
SUBCLINICAL: The dog appears normal in this phase and can stay in this phase for months or even years. The only hint that your pet is positive is that the platelet count (cells that help your animals blood clot) will be decreased. Your pet will show up positive on our Ehrlichia tests and medications will be dispensed.
CHRONIC: The dog gets sick again, and may have abnormal bleeding due to reduced platelet numbers. Inflammation of the eyes may occur, neurological effects may also be seen.
Infections tend to produce arthritis in addition to the above symptoms.
To diagnose and treat your pet we recommend to be tested once yearly, with your heartworm test. If your pet comes back positive, then we will dispense 3 weeks worth of medications. The following year, you will need to retest your pet, and if at that time, your pet is still positive, then we will place your pet on another round of medications.
For more information on human infection try:
http://www.cdc.gov/ncidod/dvrd/ehrlichia/Index.htm