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11 Early Signs of Rocky Mountain Spotted Fever in Dogs

Medically reviewed by Dr. Irish on July 20, 2023

If you’re a pet owner, you’ve probably encountered a tick, and if you’re anything like me, just talking about them makes you itch!

They’re small, difficult to detect, and hard to get rid of.

Unfortunately, ticks can transmit a number of illnesses beyond Rocky Mountain spotted fever (RMSF) including canine Ehrlichiosis, Anaplasmosis, Babesiosis, Bartonella, and Hepatozoonosis.

In this post, we’ll cover the full spectrum of how to protect your dog against Rocky Mountain spotted fever.

We’ll discuss the types of ticks that transmit the Rocky Mountain spotted fever in dogs, clinical signs of the disease, diagnosis, and treatment options.

What is Rocky Mountain Spotted Fever in Dogs?

Rocky Mountain spotted fever (RMSF) is caused by an infectious bacterium known as Rickettsia rickettsii. It’s transmitted to dogs through the bite of an infected tick.

People can contract Rocky Mountain spotted fever, but they can’t get it through their dogs. The exception would be if the person contracted the disease through the bite of an infected dog.

The ticks known to carry the disease (described in more detail below) include the:

  • American dog tick
  • Rocky Mountain wood tick
  • Brown deer tick

While it’s good to know the different types of ticks that transmit disease, it can be hard to identify the exact tick species you’re dealing with, unless you’re an expert. The best thing you can do is protect your dog from all tick bites, regardless of the type.

RMSF is a serious tick-borne disease that can lead to multi-system organ failure in dogs in severe cases.

How to Avoid Ticks

The easiest way to avoid tick bites is to stay away from areas where they live. There are a variety of tick species in the environment. Some prefer to hang out in tall grass and others hide beneath piles of dead leaves.

Unfortunately, dogs are very susceptible to tick bites and sometimes it’s nearly impossible to avoid them.

A healthy adult dog needs to get out for exercise and potty breaks. Unless you live in the middle of a city, there’s a good chance your dog is going to come in contact with a tick at some point.

You can try to avoid tall grass, piles of leaves, or walks through the woods when ticks are at their most active, but even that may not help.

The best thing you can do for your dog is to perform regular tick checks on your dog, regularly and consistently use a tick control product, and remove ticks as soon as you notice they are attached.

rocky mountain spotted fever in dogs

How Do Ticks Transmit Disease to Dogs

Diseases like Lyme disease and Rocky Mountain spotted fever in dogs are transmitted through a tick bite. Disease-causing bacteria or viruses can be released into the dog’s bloodstream through the bite of an infected tick.

Ticks attach themselves to people and pets very easily. All you have to do is brush past a blade of grass with a tick on it. They can also be found under piles of leaves, in the brush, and in tall grass.

Ticks travel well from host to host, unfortunately. For that reason, it’s not impossible to find ticks in your backyard or even at a local dog park.

While it used to be thought that the tick needed to remain attached for several hours to transmit the infection, more recent research has shown that this can occur within minutes. 

Rocky Mountain Spotted Fever in Dogs
By Malcolm Weir, DVM, MSc, MPH; Ryan Llera, BSc, DVM; Cheryl Yuill, DVM, MSc, CVH

Ticks to Watch Out For

The species of ticks that carry the bacterium R. Rickettsiii depend on the geographical location. As ticks spread across the United States and Canada, it’s becoming increasingly harder to avoid them.

The ticks mentioned below are known carriers of RMSF in dogs. However, keep in mind that there are a number of different tick species throughout the world, and they all have the potential to spread disease.

Tick populations can be influenced by climate, habitat, and host availability. This makes it difficult to predict and control their spread.

American Dog Tick (Dermacentor variabilis)

The American dog tick, also known as a wood tick, is common in the United States and Canada. These ticks are brown in color with distinct white or yellow markings on their back.

Wood ticks can be found in grassy or wooded areas.

Rocky Mountain Wood Tick (Dermacentor andersoni)

According to the CDC, Rocky Mountain wood ticks (as the name implies) are found in the western United States and western Canada.

As the name implies, these ticks are common to the Rocky Mountain states including:

  • Arizona
  • Colorado
  • Idaho
  • Montana
  • Nevada
  • New Mexico
  • Utah
  • Wyoming

These ticks have a brownish-red body with gray-blue markings. Females can reach up to 1 centimeter when fully engorged with blood while males are a little smaller.

This particular tick is also known to spread Colorado tick fever, in addition to RMSF, to animals and humans.

Brown Dog Tick (Rhipicephalus sanguineus)

Brown dog ticks are found worldwide.

They have a reddish-brown color and are relatively small. Like any tick, dog ticks can show up in kennels, homes, fields, and forests. In addition to transmitting RMSF, brown dog ticks can also spread canine ehrlichiosis and canine babesiosis.

What Are the Symptoms of Rocky Mountain Spotted Fever?

Clinical signs of the disease may not be apparent in the early stages. The onset of symptoms typically happens within 2 – 14 days after the dog is bitten by an infected tick.

Some early signs of RMSF in dogs can be mild and nonspecific. Sometimes they’re missed or passed off as something else. Dogs may have one or more of the following clinical signs:

  • Fever
  • Loss of appetite
  • Abdominal pain
  • Lethargy
  • Joint pain
  • Muscle pain
  • Swollen lymph nodes
  • Vomiting
  • Diarrhea
  • Coughing
  • Swelling of the face or legs
  • Depression

In severe cases, there can be damage to blood vessels that look like round, purplish red spots on the skin (petechiae) These are found on the eyelids, mouth, and belly. The belly doesn’t have much fur to obstruct the view.

The cause is from bleeding below the tissue surface caused by tiny hemorrhages, because tick borne illnesses cause trouble with blood clotting.

How Doctors Diagnose Rocky Mountain Spotted Fever in Dogs?

The veterinarian will evaluate clinical features and may decide to go ahead with antibiotic treatment while waiting for test results.

The risk of administering antibiotics is far less than the risk of allowing Rocky Mountain spotted fever to progress. Dogs not treated early enough could develop a more serious, or even deadly, infection.

Diagnostic tests may include the following:

Enzyme-Linked Immunosorbent Assay (ELISA)

This blood test, similar to the test mentioned below, is used to detect antibodies in the blood. Although both tests are similar, it’s thought that the ELISA test may give fewer false negatives. These are also known as serologic tests.

Indirect Fluorescent Antibody Test (IFA)

This test requires the submission of two blood samples. One sample is collected at the time of suspected illness. The other sample is collected several weeks later.

The test works by mixing a small sample of the dog’s blood with a solution that contains a piece of the disease-causing germ. If the dog’s immune system has ever encountered that germ before, it will make special proteins called antibodies that stick to the germ in the solution.

These antibodies are then made visible by adding special substances that make them light up under a microscope.

The more glowing spots that show up on the slide, the more antibodies the dog has and the more likely it is that the dog has been exposed to the disease.

By checking for these antibodies, the test can help determine whether the dog has been infected with the tick-borne illness.

Blood Tests

Veterinarians may order a complete blood count and serum blood chemistry profile.

When a veterinarian requests blood tests to diagnose RMSF in dogs, they’re looking for low protein levels, abnormal calcium levels, or any abnormalities in electrolytes. In addition, blood tests can show whether there are any abnormal kidney or liver values.

There tend to be low numbers of red blood cells in the early stage of the disease. However, once the disease progresses, the white cell count may be elevated.


In some cases, urinalysis may be performed. This is sometimes done to assess kidney health and look for proteins in the urine.

Treating Rocky Mountain Spotted Fever

RMSF is treated with a round of antibiotics and supportive therapies. The most common antibiotics used include doxycycline, tetracycline, and minocycline.

Dogs tend to respond well to antibiotic treatment. In fact, you may see an improvement in your dog’s condition as early as 24 to 48 hours after the medication is started.

Preventing RMSF in Dogs

Limit exposure to ticks, especially during peak tick months.

If you live or are visiting an area known to have ticks, make sure to thoroughly check your dog for ticks after being outside. Ticks love to find a warm space to embed and tend to make their way to your dog’s neck, ears, armpits, belly, etc. That said, they can embed anywhere on your dog.

Purchase prescription or over the counter tick control products from the pet store. Tick prevention medications should be used year-round in areas where there is increased risk of infection.

Is Rocky Mountain Spotted Fever Curable in Dogs?

Yes, RMSF is curable with antibiotic therapy.

How Long Does It Take a Dog to Recover From Rocky Mountain Spotted Fever?

Dogs will recover either during their course of antibiotics or after completing the antibiotics. Note: Do not stop giving your dog antibiotics even if he or she appears to be better.

Is There a Vaccine to Protect Dogs From Rocky Mountain Spotted Fever?

There is no vaccine to protect dogs from RMSF as of 2022. A review in the National Library of Medicine, A Vaccine for Canine Rocky Mountain Spotted Fever: An Unmet One Health Need, suggests that the possibility of creating a live, attenuated vaccine is currently being explored.

You may be interested in reading: The 4 Important Core Vaccines Your Indoor Cat Requires or How Many DA2PP Shots Does My Puppy Need.

Can My Dog Get RMSF Twice?

Dogs that have recovered from RMSF may develop lifelong immunity. That doesn’t mean your dog is safe if another tick bites him or her. Remember, ticks can transmit a variety of diseases.

13 Reasons Why Your Dog is Throwing Up Brown Liquid

Anaplasmosis in Dogs: 5 No-Fail Ways to Prevent Tick Bites

23 FAQ’s About Lyme Disease in Dogs


To put it bluntly, ticks are gross. Nobody loves them. Unfortunately, they’re a part of a pet owner’s life and they’re here to stay.

As pet parents, the best we can do is offer regular tick control. We can try to stay away from places where ticks like to hide (tall grass, etc.), but it’s not a fool-proof method. You can just as easily carry a tick into the house on your own clothing.

Likewise, other pets can bring ticks into the home.

Take the time to do regular tick checks and remove any embedded ticks from your dog’s skin asap. If you haven’t started a tick control regiment already, talk to your veterinarian about the options.

Works Cited

“Rocky Mountain Spotted Fever in Dogs | VCA Animal Hospital.” Vca, Accessed 2 Mar. 2023.

FOLEY.JANET. “Rocky Mountain Spotted Fever in Dogs – Generalized Conditions – Merck Veterinary Manual.” Merck Veterinary Manual, Accessed 2 Mar. 2023.

Klein, CVO, Dr. Jerry. “Dog Tick Diseases: Preventing Tick-borne Diseases in Dogs.” American Kennel Club, Accessed 9 Mar. 2023.

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