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 3 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. It is important to note that ticks do not cause Lyme disease, they merely transmit the bacteria that cause it.

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. Many cats do not show noticeable signs, despite being infected. Antibiotics are required for treatment in all cases 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 (see Disorders Affecting Multiple Body Systems of Dogs: Lyme Disease (Lyme Borreliosis) in Dogs).

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.

Last full review/revision July 2011 by Otto M. Radostits, CM, DVM, MSc, DACVIM (Deceased); Eugene D. Janzen, DVM, MVS; Jodie Low Choy, BVMS; Dennis W. Macy, MS, DACVIM; Dudley L. McCaw, DVM, DACVIM (Small Animal, Oncology); Barton W. Rohrbach, VMD, MPH, DACVPM; J. Glenn Songer, PhD; Richard A. Squires, BVSc (Hons), PhD, DVR, DACVIM, DECVIM-CA, MRCVS; Bert E. Stromberg, PhD; Joseph Taboada, DVM, DACVIM; Charles O. Thoen, DVM, PhD; John F. Timoney, MVB, PhD, Dsc, MRCVS; Ian Tizard, BVMS, PhD, DACVM; Max J. Appel, DMV, PhD; David A. Ashford, DVM, MPH, DS; Stephen C. Barr, BVSc, MVS, PhD, DACVIM; J. P. Dubey, MVSc, PhD; Paul Ettestad, DVM, MS; Craig E. Greene, DVM, MS; Delores E. Hill, PhD; Johnny D. Hoskins, DVM, PhD