Rocky Mountain Fever in Dogs: Causes, Symptoms & Treatment

What Is Rocky Mountain Spotted Fever?

Rocky Mountain spotted fever is a debilitating disease caused by a species of bacteria known as Rickettsia rickettsii. The American dog tick (Dermacentor variabilis) and the Rocky Mountain wood tick (Dermacentor andersoni) are both the most common vectors of this disease.

How Is It Acquired?

The disease is transmitted when an infected tick feeds on the dog and delivers the rickettsial bacteria into the dog's bloodstream through the saliva. However, this does not occur right away. In order to transmit the disease, the tick must be attached to the dog's skin for at least 5 to 20 hours, according to veterinarian Ann Marie Manning in Rocky Mountain Spotted Fever.

Since it is carried by ticks, Rocky Mountain spotted fever is more likely to occur in the months when ticks are more active. This means dogs are most vulnerable in the spring and summer months from April to September.

Ticks love to hide in high grass and bushes where they eagerly wait for a warm body to pass by. These critters are capable of detecting the heat or carbon dioxide emitted by a living animal walking by, and they are ready to hitch a ride onto their next blood meal.

Curiously, despite its name, Rocky Mountain spotted fever is not limited to the Rocky Mountain states. Rather, it is pretty widespread and affects several areas of the United States. The East Coast, Midwest, and plains regions are the locations most likely to be affected. Howard T. Ricketts, an American pathologist, was the first to identify the infectious organism responsible for this disease, hence the name Rickettsia.

Symptoms of Rocky Mountain Spotted Fever

If your dog was bitten by a potentially infected tick, what happens now? Once the rickettsial bacteria have been delivered into the dog, it generally takes between 2 to 14 days for the symptoms of Rocky Mountain spotted fever to manifest. Unlike humans who typically develop a skin rash, dogs usually exhibit a fever ranging from 102.6 to 104.9 degrees Fahrenheit about five days after the bite.

Because the rickettsial organisms tend to invade and kill blood cells, affected dogs may develop nose bleeds, bloody urine, bloody stools, presence of petechiae (pinpointed hemorrhages under the skin), and hemorrhages in the retina of the eye.

Other accompanying symptoms of Rocky Mountain spotted fever are lethargy, decreased appetite, enlarged lymph nodes, and swollen joints. Severely affected dogs may develop neurological signs, renal failure, and disseminated intravascular coagulation, a condition where platelets and clotting factors are destroyed.

Diagnosis

If you notice any unusual symptoms that suggest this disease regardless of any knowledge of tick exposure, it is imperative to have your dog evaluated by a veterinarian immediately. Because Rocky Mountain spotted fever may resemble a variety of other infectious and non-infectious diseases, several diagnostic tests may be required to confirm or rule out this disease. The test results and the clinical signs the dog manifests combined with its seasonal occurrence are often sufficient to confirm this condition.

Complete blood counts may reveal a mild degree of decreased platelets. Biochemistry profiles often find increased liver enzymes (serum alkaline phosphatase and alanine aminotransferase). Testing the dog's antibodies is one of the most useful means to detect infection with Rickettsia ricketsii. A dog with an active infection when tested serologically typically has a heightened antibody count.

Since Rocky Mountain spotted fever symptoms may mimic other tick-borne diseases such as Lyme disease and Ehrlichia, the veterinarians may submit blood for a "tick panel" that includes titers for each of the three diseases. Direct immunofluorescent testing of the tissue biopsies is one of the most effective venues for a rapid diagnosis.

Treatment and Prognosis

Tetracycline antibiotics are the medications of choice for treatment. When Rocky Mountain spotted fever is suspected, treatment should be initiated immediately. A delay or the wrong choice of antibiotics may result in a fatal outcome.

Dogs generally start responding to the antibiotic treatment within 24 to 48 hours. The antibiotics are prescribed for two to three weeks and should not be stopped earlier, even if the dog is doing better. Severe cases may require hospitalization.

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The prognosis for Rocky Mountain spotted fever varies depending on its severity and the time lapse before treatment is started. Generally, when treatment begins immediately, the prognosis is good. However, lack of treatment or delays of hours or days may result in long-term consequences with devastating consequences on the nervous system and even death according to Pet MD.

The good news is that once infected, it appears that dogs that recover from Rocky Mountain spotted fever are immune to reinfection for years, explains veterinarian Holly Nash in the article "Rocky Mountain Spotted Fever in Dogs."

Preventing Rocky Mountain Fever in Dogs

Good tick control is fundamental to preventing this potentially devastating disease.

Thoroughly Inspect Your Dog

Dogs that spend time outdoors should be inspected thoroughly for ticks with owners paying special attention to areas where ticks like to hide such as under the armpits, between the toes, and below the ear flaps.

Tick Control

There are several good tick control products on the market such as topical products to apply monthly and tick collars to prevent ticks on dogs. Rodent control also plays a big role since they are involved in the life cycle of ticks.

Correct Tick Removal

If a tick is detected and is attached to the dog's skin, it is important to remove the tick in the correct way to prevent harmful secretions from spreading. Always wear gloves when removing ticks. Ticks should not be removed with the bare hands because while dogs do not spread Rocky Mountain spotted fever directly to humans or other dogs, humans may get it indirectly by contacting the tick's secretions when removing ticks.

Unfortunately, there are no vaccinations against Rocky Mountain spotted fever; Prevention is the key to keeping the disease in dogs at bay. Put your dog on a good tick preventive product, and always check for ticks after venturing into the great outdoors.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: How do I remove a tick from a dog?

Answer: If a tick is found embedded in the dog's skin; wear a pair of latex gloves, and, using tweezers, grasp the tick's head firmly as close as possible to the dog's skin. Pull the tick straight out from the skin using slow, firm traction, Never squeeze or twist, or the tick may release more pathogens. Preserve the tick in a jar of alcohol with a label and date just in case your dog gets a tick-borne disease or shows symptoms of one.

© 2011 Adrienne Farricelli CPDT-KA, Dip.CBST

Comments

moonlake from America on December 14, 2011:

Good hub. I have never heard of Rocky Mountain Spotted Fever. People and pets do get Lyme’s Disease from ticks here.

Deborah Brooks Langford from Brownsville,TX on December 14, 2011:

this is a great HUB.. very useful.. I have a cat that goes out back but mostly stays in the house,.. I keep her with tick and flea medicine from the vet.. I thank you.. love the HUB.. I voted up and useful