Dog: Lyme Disease

General information

Other common/scientific names: borreliosis, Borrelia burgdorferi

The tick population in the United States is exploding due to changing climate (less harsh winters), suburbanization and the increase in the deer population . Because of this, ticks are moving into new areas and bringing new diseases. As a result, tick-borne diseases in dogs are increasing. These diseases include anaplasmosis, babesiosis, ehrlichiosis, borreliosis (Lyme disease) and Rocky Mountain spotted fever. These diseases are typically infections of the blood. Because these infections are transmitted by a tick bite, a dog may be infected with more than one of these organisms at the same time.


Lyme disease is caused by the bacteria Borrelia burgdorferi. These bacteria are very good at hiding in different cells in the body. Because of this, treatment may not eliminate the bacteria from the dog’s body. This can result in relapses of clinical signs and chronic inflammation even after long term treatment. The Borrelia bacteria also have the ability to produce an immune-mediated disease. This results when the dog’s own immune system becomes over-reactive resulting in the formation of immune complexes which are deposited in various organs (joint, kidney, heart) causing inflammation and disease.

Abb. GSR8EBJW: Borrelia, microscope.


Dogs acquire Lyme disease by being bit by a tick carrying the bacteria. The deer tick (Ixodes scapularis) transmits the Borrelia organism. Transmission of the bacteria from the tick to the dog takes at least 24 hours. Therefore, promptly removing any ticks from your dog’s body can prevent the spread of Lyme disease.

Lyme disease is seen most frequently in the Northeast, upper Midwest and mid-Atlantic United States where the deer tick is most common. The disease is usually transmitted from April to October when ticks are most active.

Cardinal symptom



It is important to remember that 95% of all exposed dogs will not show any signs of Lyme disease. Therefore, dogs are much less prone to showing symptoms than humans. Additionally, dogs will not show signs of Lyme disease until months after they have been bitten by an infected tick. Dogs can develop lameness, swollen painful joints, fever, lethargy and loss of appetite. Although uncommon, more serious symptoms include signs associated with immune-mediated chronic renal failure and heart disease.


Test results regarding Lyme disease can be confusing since many dogs will test positive but show no clinical signs of the disease. Therefore, your dog should only be diagnosed with Lyme disease if he or she is showing clinical signs and has a positive blood test.

As part of your dog’s annual preventative health care, your veterinarian may recommend a four way blood test to detect heartworm infection, Lyme disease, ehrlichiosis and anaplasmosis. This test is performed in your veterinary clinic while you wait and measures antibody levels. A positive result for Lyme disease, however, only indicates past exposure to the bacteria not an active infection. Because of this, dog owners should not panic if their dog tests positive for Lyme disease. Other tests can be sent to a laboratory to confirm the antibody levels and to detect the Borrelia DNA in the blood.


Lyme disease is treated with long term antibiotics. Dogs which have joint pain can benefit from anti-inflammatory medication.


The prognosis is good since most dogs recover quickly with treatment. However, Lyme disease does have the potential to cause chronic kidney and heart disease.


There are currently four vaccines available in the United States marketed prevent Lyme disease. However, controversy exists regarding the use of these vaccines. Some scientific studies show that the vaccines fail to protect the dog against Lyme disease. Other concerns are that the vaccine can trigger immune mediated disease in the dog. And, since many dogs with the Lyme bacteria do not show clinical signs, vaccinating these infected dogs could cause serious health problems. It is important to discuss vaccination with your veterinarian. Your veterinarian can determine if your dog is at risk for developing Lyme disease and should be vaccinated.

Dogs which go outdoors in wooded, tick infested areas should have some form of tick protection such as:

Because of the warmer winters, tick protection is recommended year around.

While the topical spot-on medications are the best defense in preventing tick-borne diseases, checking your dog for ticks after walking or playing in a wooded area is recommended since it takes several hours for an attached tick to transmit disease. This is especially important if you live in a tick infested area.


When applying the topical, spot-on medications, be sure to part the hair and apply the medication directly to the skin. Do not bath or allow your dog to swim for 2 days after application. The product may need to be re-applied more often than every 30 days.

Update version: 4/24/2014, © Copyright by
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The information offered by enpevet Ltd. is intended solely for information purposes and and does under no circumstances replace a personal consultation, examination or diagnosis through a veterinarian. Thus, the information serves as an addition to the dialogue between pet owner and veterinarian, but can never replace the visit to the veterinarian. enpevet® would like to ask all users, whose animals have health concerns, to see a veterinarian as required. If you have any questions regarding the health of your animal, we recommend that you turn to your trusted veterinarian , instead of starting, changing or breaking off treatments on your own. The content of enpevet® cannot and should not be used for making your own diagnoses or for the selection and application of treatment methods.