Pets & Lyme Disease

Lyme Disease and Your Pet

What You Need to Know


What is Lyme Disease?

Lyme disease is a bacterial infection transmitted by the bite of an infected Ixodes scapularis tick, commonly known as the black-legged tick or the deer tick. 

The blacklegged tick goes through three life stages - larvae, nymph and adult.  Larvae tick are extremely small, the size of a period at the end of a sentence, while adult females who have fed can be as large as a raisin.

Black-legged ticks acquire B. burgdorferi bacteria by feeding on infected small mammals and birds – as soon as they feed they molt to the next life stage.  That new life stage is then capable of transmitting the bacteria to you or your pet.  However the tick needs to be attached for at least a day for transmission, so ticks found walking on your pet are not a risk provided they are promptly removed.

Symptoms in Animals:

Lyme disease affects pets in various ways.  Some animals may display no signs of disease.  Others may develop fever, loss of appetite, painful joints, lethargy and vomiting.  If left untreated, the spirochete may cause damage to an animal’s eyes, heart, kidneys and nervous system.  Lyme disease has been diagnosed in humans, dogs, cats, horses, goats and cattle.  Birds, reptiles and amphibians are not at risk.

Dogs and Cats

Some infected dogs and cats may show no signs of disease.  Others may exhibit lameness, fever, loss of appetite, fatigue, visual impairment and abnormal breathing.  Dogs may show signs of neurological involvement, such as uncharacteristic aggression, confusion, overeating and seizures.  Dogs may also suffer kidney failure.


Many infected horses display no symptoms.  Infected horses typically do not have fever but may have lameness, laminitis, depression, appetite loss or visual impairment.  There are reports of spontaneous abortion and neurological signs including head tilt, difficulty swallowing or aimless wandering. 



 If you are concerned that your pet may have Lyme disease, have the pet examined by a veterinarian as soon as possible - the sooner the disease is diagnosed, the easier it is to treat.  Diagnosis of Lyme disease is based upon careful analysis of the animal’s clinical presentation, its risk of exposure to ticks, and lab test results.  Tests may be conducted on ticks found on the pet, or on a sample of your pet’s blood.  Blood tests typically indicate if your pet has been exposed to the bacteria – a positive test does not necessarily mean that the pet is still infected.


 A course of antibiotics is usually effective in treating Lyme disease.  The earlier treatment is started, the more successful the outcome.  Long-standing disease may respond slowly and require longer periods of treatment.  Oral antibiotics may not eliminate widespread or neurological forms of disease.  Even though clinical signs usually resolve with treatment, a low level of bacteria may remain and cause recurrent disease episodes.

Tick Bite Prevention:

 Apply a veterinary approved tick preventative to your pets to help protect them from disease.  Not all products can be used on all species; for example, products containing permethrin or pyrethroid ingredients are toxic to cats – do not use these products in a household with cats. Always follow the manufacturer’s or veterinarian’s instructions and never apply multiple repellents to your pet – the mixture of different chemicals could make it very sick.

Be on the lookout for ticks on yourself and your pets – ideal Blacklegged tick habitat includes long grass, leaf litter, shrubby and wooded areas, and vegetation on sand dudes.


Conduct frequent tick checks – daily! 


Use our guide on proper tick removal to remove any ticks and remember to save Live ticks for testing.