Tick-Borne Diseases in Dogs

Itchy dog

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Most dogs love being outdoors. As much as we want to see them happy, we also need to be aware of potential hazards. Ticks love dogs, and they can transmit a variety of diseases to them. It is important to have a basic understanding of the tick and what they can pass to your dog and even to people. This article discusses common tick-borne diseases, vital information about each one, and ways to prevent your dog from being exposed.

Anaplasmosis

There are two known forms of Anaplasmosis: granulocytic and infectious cyclic thrombocytopenia. Granulocytic Anaplasmosis, which affects the white blood cells, is the most common form in dogs. Anaplasma phagocytophilum is the organism that causes an infection. It is transmitted via a bite from an Ixodes tick, often called the deer tick, black-legged tick, or bear tick. The tick must be attached for at least 24 hours before it can transmit Anaplasma. It takes about one to two weeks for a dog to develop clinical signs.

Clinical signs may be vague, but if noted, may include lethargy, decreased appetite, fever, and lameness. Less common signs include vomiting, diarrhea, coughing, and difficulty breathing. Anaplasmosis is diagnosed using blood tests and a urinalysis. If the dog is lame, radiographs and joint fluid analysis are usually included. Treatment includes antibiotics, pain relievers, and anti-inflammatory drugs.

Ixodes (Deer) Tick
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Babesiosis

Babesiosis occurs when a Babesia-infected tick bites a dog and releases Babesia sporozoites into the dog’s bloodstream. There are several species of Babesia that affect dogs in the U.S., but the most common species is Babesia canis. A tick must feed for two to three days before it can transmit Babesia. It can take up to two weeks for a dog to develop clinical signs, however, some cases are not diagnosed for months to years.

Affected dogs may experience lethargy, decreased appetite, anemia, fever, jaundice, weight loss, and discolored stool. Babesia may also involve the spleen and the lymph nodes. Babesia organisms can sometimes be identified on a blood smear (blood placed on a slide and examined under a microscope). Antibody and DNA testing have also been used to diagnose Babesiosis. Treatment depends on the severity of the clinical signs, but can include antibabesial drugs and antibiotics, fluid therapy, and blood transfusions.

Ehrlichiosis

In the U.S., Ehrlichia canis infection is spread by the bite of the brown dog tick, but it is a worldwide disease. These organisms affect and live within white blood cells. An infected tick must attach to the dog for 24-48 hours to transmit Ehrlichia canis. It can take from one to three weeks for clinical signs to develop. There are three clinical stages of Ehrlichiosis: Acute, Subclinical, and Chronic.

The acute phase occurs one to three weeks being bitten by the infected brown dog tick. Clinical signs may include listlessness, fever, and neurologic signs, while the organism is invading the white blood cells. The dog may also experience a low platelet count and enlargement of the spleen, liver, and/or lymph nodes. During the subclinical phase, the dog may appear normal. They can stay in this phase for months to years and may only show mild changes on lab work. During the chronic phase, the dog may become sick again. Clinical signs may include abnormal bleeding, uveitis (deep inflammation of the eyes), neurologic effects, and glomerulonephritis (urinary protein loss due to kidney inflammation.

There are two main tests for Ehrlichia: PCR testing for Ehrlichia DNA or blood testing for Ehrlichia antibodies. Treatment includes antibiotic therapy. In more complex cases, other medications like steroids may be necessary.

Brown dog tick
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Lyme Disease

Lyme disease is one of the most common zoonotic diseases in the U.S. When a dog is bitten by a deer tick carrying the bacterial organism, Borrelia burgdorferi.Lyme disease is transmitted. It has been reported in every state in the U.S., however, it is more prevalent on the east coast than on the west coast. The infected tick must attach to the dog for a minimum of 48 hours to transmit the Borrelia organism. It may take months for clinical signs to develop.

Some dogs may not experience clinical signs of Lyme disease. If they are seen, they may include fever, loss of appetite, painful or swollen joints, lameness that comes and goes, swollen lymph nodes, and lethargy. If left untreated it can lead to damage in the kidneys, nervous system, and heart. Diagnosis is often based on signs and history, however, blood tests may be helpful in detecting chronic infection. Antibiotics are the main treatment, however, other therapies may be needed based on the systems being affected.

Dog with tick
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Rocky Mountain Spotted Fever

Rocky Mountain Spotted Fever (RMSF) is transmitted when a dog is bitten by an infected tick carrying the Rickettsia rickettsii organism. The Rocky Mountain wood tick, the American dog tick, and the brown dog tick can all transmit RMSF. Research has shown that transmission of the Rickettsia organism may occur sooner in fed ticks (minutes) versus unfed ticks (hours). Clinical signs can take up to 14 days to develop.

RMSF may affect any organ in the body. Clinical signs may be mild, or severe enough to result in death. Common clinical signs are listed below:

  • Fever
  • Lethargy
  • Inappetence
  • Pain
  • Eye/Nose discharge
  • Nosebleed
  • Cough
  • Enlarged lymph nodes
  • Lameness
  • Skin necrosis/sloughing
  • Hemorrhage
  • Peripheral swelling (e.g. swelling of limbs)

Blood tests are used to help diagnose Rocky Mountain Spotted Fever. Treatment relies on the use of antibiotics. A response may be seen within 24 to 48 hours, however, advanced cases may not respond at all. Blood transfusions to treat anemia and other supportive therapies may be needed.

Rocky Mountain Wood Dog Tick
 Milehightraveler/Getty Images

How to Prevent Infection

  • Routinely checked for ticks after your dog has been outside. If they have been in tall grass and brush, pay close attention.
  • If you see a tick on your dog, remove by using fine-pointed tweezers to grasp the head of the tick (right where it enters the skin). Pull the tick straight off, making sure not to grasp or squeeze its body. Your veterinarian is also available to help you.
  • Ask your veterinarian whether a vaccine is available to help protect them.
  • Your dog should be treated regularly with an effective, tick-control product. Your veterinarian will make the best recommendation.
If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Ehrlichiosis In DogsVCA Animal Hospitals, 2020

  2. Rocky Mountain Spotted Fever In DogsVca_Corporate, 2020

  3. Preventing Tick Bites On PetsCenters For Disease Control And Prevention, 2020