My Dog Tested Positive for Lyme Disease–Now What?
The positive test means that your dog has been bitten by a tick and exposed to Lyme disease.
Exposure to Lyme disease is very different in dogs compared to exposure in people. The good news is that 90-95% of dogs exposed to Lyme disease will be perfectly fine and never develop the illness. The bad news is that your dog was bitten by a tick so we need to be sure effective tick preventatives are being used correctly, year-round. Even in winter, we have occasional mild temperatures and the ticks will be active. Most important is the fact that the ticks in your area are carrying Lyme disease, so if you find an attached engorged tick on yourself or a family member, you need to immediately contact your physician.
We are concerned with the 5-10% of exposed dogs that become ill with Lyme disease. Usually, these dogs would show Lyme arthritis with possible lameness, lethargy, fever, and decreased appetite. Prior to (or soon after starting) treatment, a quantitative C6 antibody test is run and repeated 3-5 months following treatment. This additional test helps us confirm a response to treatment and may help determine future exposure to Lyme disease. Symptomatic dogs are then treated with an antibiotic (usually doxycycline) and they usually respond and appear normal within a few days. Nevertheless, the current consensus is to keep these dogs on doxycycline therapy for L month. lf they do not respond in a day or two, a diagnostic workup is recommended since 40% of dogs with suspected Lyme arthritis actually have some other problem causing their clinical signs.
ln rare cases (< 2% of those infected), dogs may develop a dangerous and potentially fatal kidney disease called Lyme nephritis. Technically, Lyme nephritis is a cause of protein-losing nephropathy due to immune-complex glomerulonephritis. This is the fancy way of saying the kidneys are no longer able to keep protein in the blood and the protein gets washed out into the urine. The important point is that we need to monitor alt Lyme-positive dogs, whether they are acting sick or not, by checking their urine for protein (and in some cases perform other diagnostic tests) for the rest of their lives, whether treated or not, to detect this rare but potentially fatal form of Lyme disease.
Lyme vaccines are currently available to help prevent Lyme disease in dogs. Although these vaccines are not 100% effective, we have seen so much exposure to Lyme disease in our area, our hospital has decided to recommend vaccination of most dogs as an added layer of prevention, in addition to using excellent tick control products year-round.
The take-home message is that the best thing to do is prevent exposure to Lyme disease by using excellent year-round tick preventatives and monitoring our pets (and people too) for any attached ticks.