Lyme Disease
by Dr. Dave Erlewein
Priscilla and Prezlee, a two-year-old dog, came flying into the office during lunch hour a couple weeks ago. Priscilla was “flying” because of acute anxiety and Prezlee, well, he’s two and flying is his modus operandi! The cause of Priscilla’s angst was a big, fat tick on the side of Prez’s muzzle and while she was shrieking, “Get it off, get it off!” Prez was busy with his front paws on the counter trying to get into the candy dish.
Normally, I would not have witnessed this waiting room tableau, but I just happened to be at the front desk getting ready to fax some records to a hospital in another state. I grabbed Prez by the collar, told Priscilla to follow me and led the twosome into an exam room. Priscilla let loose with a rapid fire, nearly incoherent, barrage of questions. Several times I heard the words “Lyme disease” but the rest just ran together.
Removing the tick was easy. Calming down Priscilla? Not so much. She had read and heard too many scary stories about Lyme disease in people and assumed dogs would be affected the same way. She was sure that Prez would either die or spend the rest of his life with painful and disabling arthritis. I was able to relieve her anxiety and convince her that Prez should have many more comfortable years of life.
The tick I removed from Prez was an American dog tick, and these ticks do not carry Lyme disease. It is the black legged deer tick, Ixodes scapularis, that carries and infects humans and dogs, with Borrelia burgdorferi the cause of Lyme disease in the upper Midwest and the Atlantic coastal states. In northern California, there is an Ixodes tick that primarily feeds on reptiles that serves as a source for Borrelia.
A simple tick bite will not spread the disease. If the tick falls off, is rubbed off, or otherwise removed within 36-48 hours, infection cannot occur. A feeding tick is a blood sucker and to continue sucking it must keep the blood of its host from clotting. It does this by regurgitating enzymes from the digestive track. If the tick is harboring the Lyme organism, it will enter the dog via the regurgitation process.
Lyme disease is a relatively minor infection in most dogs and symptoms will not appear for weeks to months after infection. The usual manifestation is lameness and/or joint swelling that is suggestive of arthritis. Some dogs will have a fever. Young dogs are more commonly affected than adults. The majority of cases will respond rapidly to a course of relatively inexpensive antibiotics. Most cases do not require hospital treatment.
Rarely, however, is there a serious complication of Lyme disease in dogs. A few dogs will develop severe kidney disease from long term stimulation of the immune system due to a hidden (latent) infection with the organism. This type of kidney damage can be life threatening and hospital treatment is usually necessary. A simple screening test for Lyme disease is available but it only indicates exposure to the organism. If the screening test is positive, other blood tests are necessary to determine if there is an active infection. The Lyme disease organism is very difficult to detect.
Preventing tick attachment is the best means of keeping your dog free of Lyme disease. There are several effective tick control products available that either kill the tick or cause it to drop off within 48 hours. The 48-hour time window is important to remember as even simply pulling of the tick will prevent the disease in this period. Always check your dog over after a jaunt in an area known to be infested with ticks. A thorough coat check at least every other day during the tick season is a good idea if you live in an area where ticks are prevalent.
There are vaccines available for prevention of Lyme disease. All are only helpful when administered prior to tick exposure. They are not at all helpful in treating post-bite exposures. All require annual boosters.
Use of the vaccine is considered controversial to some veterinarians. The main argument against vaccination seems to go that since more than 90 percent of the infected dogs will never get sick, and that the majority of the remaining 10 percent are easily treated with inexpensive antibiotics, vaccination is just not worth the expense. In addition, some researchers feel that since we do not know exactly which proteins cause the severe kidney disease in some dogs, the vaccines might contain some hazardous materials. On the other hand, the idea of vaccination is to prevent infection and just because a disease is not life-threatening does not mean we should not prevent it (think influenza vaccines in humans).
In areas where Lyme disease is not prevalent, a veterinarian presented with a dog with signs of arthritis might not utilize an antibiotic treatment. In addition, a dog harboring the organism for several months can act as a source of the disease if a tick attaches itself.
There is, however, absolutely nothing controversial about tick control. It is crucial to use a tick control product on your dog if you live in or travel to an area where Lyme disease is found. Lyme disease is a regional disease. Find out if it occurs in your area!
You can learn more at www.lymediseaseassociation.org/index.php/resources/cases-a-other-statistics.
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