Lyme Disease in Dogs & Cats - Protecting Your Pets


Borreliosis, more familiarly known as ‘Lyme’ disease, is caused by the spirochete bacterium Borrelia Burgdorferi. The disease is transmitted to humans and animals primarily by adult (and to a far lesser degree the nymph) stages of the black-legged tick, lxodes scapularis. Originally, the tick was called a “deer tick,” because of the false belief that this tick was only found on deer. As it happens, deer are only one of many animals that carry this tick. Humans, dogs, cats, mice, raccoons, birds and many other species of animals can act as hosts for black-legged ticks.

Adult ticks are reddish-brown and almost one-eighth of an inch long. They are usually found where there is heavy vegetation, and in wooded or grassy areas. Although ticks are predominately active during the spring and summer, they can also be active whenever the weather approaches or exceeds freezing. If there is snow on the ground, there will not be much activity, but if there are several warm days in a row, the ticks may be active.

Lyme disease is not a zoonotic disease, meaning it cannot be directly transmitted from an animal to a human. Rather it requires a vector host, which in this situation is the Ixodes tick. If there are no ticks or potential exposure to ticks, then neither you or your pets can become infected. This is the reason why preventing exposure to ticks is important.

Protecting Your Pets from Ticks

  • For Lyme disease to be contracted by a dog, a tick must be attached to your dog for at least forty-eight hours and your cat for at least eighteen hours. Therefore, the best means of avoiding Lyme disease is to remove ticks, as soon as they are found. Daily inspections of your dog and cat are recommended, especially in the spring and summer.
  • In addition to regularly checking for ticks, applying topical parasiticides (on dogs only!) will help reduce the risk. There are several tick products available, so it is best to discuss the appropriate choice with your veterinarian. This is particularly important to do, if you have any cats in your house.
  • There are several vaccines - although none for cats - available to prevent Lyme disease in dogs. The need for this vaccine should be determined on a case-by-case basis following a discussion with your veterinarian, as there can be potential reactions and a dog’s natural immunity can prevent many infections even if bitten by an infected tick.
  • Until an effective vaccine is developed for cats, the best thing people can do is to practise vigilance in finding and removing ticks before infection can occur. An even safer measure, is to keep your cat indoors, away from ticks and other dangers they can encounter in the outdoors.

Tick Remedies for Your Pets

  • If you are comfortable removing the tick, you can do it without the assistance of a veterinarian. The best way to remove a tick is to use blunt tweezers and grab the tick as close to the skin as possible. If you must use your fingers, shield them with a tissue or wear disposable gloves. The tick should then be removed by pulling it straight out. Do not twist or crush the tick as you are removing it, as it can separate the head from the body. After removing the tick, thoroughly disinfect the bite area. Your veterinarian can also send home an inexpensive plastic tool called a “tick twister” which is very effective at removing different sized ticks easily.
  • Because infectious agents can be contracted through any open lesion on the skin, it is advisable to wash your hands immediately after removing the tick to limit possible exposure to yourself.
  • After removing the tick, you may wish to preserve it in rubbing alcohol for identification. Be sure to label the container with information about the time and place, and where the tick bite occurred. This activity will help you to remember details of the incident, especially if symptoms appear.

Lyme Disease in Dogs 

An infected dog may show few signs or display a range of symptoms. The telltale rash at the infected site that is common in humans is not present in dogs.

Although there are a number of different clinical signs that a dog may show, the vast majority of dogs who develop Lyme disease develop sudden lameness and often their step is stilted and painful with swollen joints. A fever may or may not be present. It can take a number of months for these signs to manifest after exposure to infected Ixodes ticks which might complicate a diagnosis.

Lyme Disease in Cats

Many cats with Lyme disease do not exhibit any symptoms. In fact, Lyme disease is uncommon in cats. In those cats in which it does occur, the signs are similar to those in dogs, ie. lameness due to joint inflammation along with lethargy and loss of appetite.

Although the chronic debilitating form of Lyme disease found in people is uncommon in our pets, your veterinarian may want to check for it in cases of a chronic illness causing lameness and listlessness.