Following a tick bite, symptoms of Lyme disease and/or illness may not develop for several weeks or months. Symptoms of Lyme disease in dogs and cats include limping and intermittent, wandering arthritis that affects one joint one day, and the same or another joint the next day. The painful arthritic joint may be hot and swollen so that pets walk stiffly and arch their backs. Some pets are lethargic and anorexic, and have fevers.
After having Lyme disease for some time, pets may develop kidney problems because the white blood cell antibodies that attach themselves to the Lyme spirochete form clumps (antigen-antibody complex) that plug up the kidney filtering unit, the glomerulus. With glomerulonephritis, the pet loses the ability to prevent molecules like sodium from being lost in the urine. These lost sodium molecules pull water into the urine and the pet urinates large quantities. This makes the pet thirsty and drink to replenish what is lost in the urine. The tendency to urinate large quantities (polyuria) and drink large quantities (polydipsia), or PUPD, is characteristic of chronic kidney failure.
Heart and nervous system disease is also possible, but rare. Lymph nodes may swell as the white blood cells multiply to produce more immune soldiers to fight the infection.
Lyme Disease in pets is diagnosed by blood tests that show an increase in antibodies to the Borrelia organism. The amount of antibodies must increase four-fold to prove your pet has an active infection.