How is Rocky Mountain spotted fever transmitted?

RMSF is carried by the wood tick, the American dog tick and the brown dog tick and is transmitted to your dog (or yourself!) through the tick’s bite. The tick has to be attached for five to 20 hours to transmit the disease-causing bacterial organism, Rickettsia ricketsii, so there’s no need to worry if you’re able to remove the tick early. This is a great reason to do a tick check on yourself and your loved ones (two- and four-footed) after coming in from the great outdoors.

Where is Rocky Mountain spotted fever most common?

Although RMSF has been reported in most states, it’s most commonly seen in the southern Atlantic and western central states, with some involvement in mid-Atlantic and southern New England states.

What are the signs of Rocky Mountain spotted fever in pets?

Clinical signs will show up two days to two weeks following a bite from an infected tick. The most consistent symptom of Rocky Mountain spotted fever is, as you might imagine, fever! It may be hard for owners to detect fever in their pet, but generally fever is accompanied by lethargy and decreased appetite.

Once transmitted, the bacterium invades and replicates inside the endothelial cells that line the walls of small veins and arteries. The inflammation it causes there is called vasculitis, and because every inch of your dog’s body contains blood vessels, every body system can be affected.

Clinical signs can range from mild to severe, and aside from fever, they include:

  • discharge from the eyes/nose
  • bloody nose
  • enlarged lymph nodes
  • skin lesions/sloughing
  • petechial hemorrhage, or pinpoint bleeding seen in the skin
  • non-specific pain
  • redness or swelling of mucous membranes
  • 1/3 of patients will show neurologic signs

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How is Rocky Mountain spotted fever diagnosed?

Your dog’s veterinarian may suspect RMSF based on the clinical signs, but there are blood tests she can run to be sure. Often, a high antibody titer is found on presentation, but this isn’t always the case. A four-fold increase in titers over a two to three week period will confirm infection. Because time is of the essence in severely affected dogs, treatment is often initiated without definitive confirmation of the disease. In these cases, response to treatment can be enough to diagnose RMSF.

How is Rocky Mountain spotted fever treated?

Luckily, RMSF usually responds to treatment, and a reduction of clinical signs can be seen as soon as 24 hours after starting appropriate antibiotic therapy. Antibiotics should be continued until they are all gone (which may take a month), even if your pet is feeling better. For severe cases, blood transfusions and hospitalization may be required.

Because RMSF can be life threatening, it’s important to do your best to prevent it. With a myriad of parasite control options at your fingertips, there’s no excuse for not using flea and tick control. Go one extra step by performing a tick check after outings, and your furry friend will be fever free from spotted fever!

Jul 26, 2016
Pet Health

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