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Pet Owner Version

Lyme Disease (Lyme Borreliosis) in Cats


Reinhard K. Straubinger

, DrMedVetHabil, PhD, Institute for Infectious Diseases and Zoonoses, Department of Veterinary Sciences, Faculty of Veterinary Medicine, LMU

Reviewed/Revised Aug 2018 | Modified Oct 2022

Lyme disease, which is caused by the bacteria Borrelia burgdorferi and transmitted through the bite of a tick, affects domestic animals and humans. At least 4 known species of ticks can transmit Lyme disease. However, the great majority of Lyme disease transmissions are due to the bite of a very tiny tick commonly called the deer tick, or black-legged tick. The scientific name of the tick species involved on the west coast of the US is Ixodes pacificus; Ixodes scapularis is the species involved elsewhere in the United States (primarily the northeast and the Midwest). It is important to note that ticks do not cause Lyme disease, they merely transmit the bacteria that cause it. However, in some areas, as many as half of adult ticks carry the bacteria.

Although the tick prefers certain creatures—such as voles, white-footed mice, or deer—upon which to feed during the various stages of its life cycle, it is quite willing to feed on people or pets. Regardless of its stage of development (larva, nymph, or adult tick), if the tick carries the bacteria in its body, people and pets can become infected if bitten. Once a tick attaches, it takes 1-2 days for it to transmit the bacteria that cause Lyme disease, so prompt removal of ticks is important. Risk of transmission is highest during periods when the nymphs (spring) and adults (spring and fall) are actively seeking hosts.

Lyme disease occurs much more frequently in dogs than in cats. When infected, cats may show lameness, fever, loss of appetite, fatigue, or difficulty breathing. Lyme disease can also affect the kidneys, joints, nervous system, and heart. Many cats do not show noticeable signs, despite being infected.

The diagnosis of Lyme disease is based on history, signs of disease, laboratory tests, and elimination of other disorders. Additional tests may be necessary depending on which part of the body is affected. Antibiotics are required for treatment in all animals that display signs of Lyme disease. Rapid response is seen in limb and joint disease in most cases, although the signs do not completely resolve in a significant number of affected animals. The infection may persist in spite of antibiotic treatment, and a second round of treatment may be necessary. Additional therapy to help the affected organ systems and signs is also important, especially when the disease affects the kidneys, heart, or nerves.

Tick avoidance plays a role in disease control. While highly effective products (such as sprays and monthly “spot-on” products) are available for use, they must be used consistently in order to provide effective longterm tick control. Your veterinarian can recommend a product that is appropriate for your cat. Any ticks found on your cat should be promptly removed to help prevent transmission of Lyme disease and other diseases spread by ticks. Cats and other animals are not the direct source of infection in people. Pets may bring unattached infected ticks into the household, and if they then attach to another animal or person, they may transmit Lyme disease.

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