Critters on the Trail

Kyoto: Hiking from Kibune to Kurama

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Of all the bugs that worry the camper, the tick may present the greatest fear. We're not as much worried about the bite as the possibility of infection with a tick-borne disease, especially Rocky Mountain Spotted Fever or Lyme disease. The incidence of ehrlichiosis, another tick-borne disease that can infect both dogs and humans, is also reported to be on the rise.

The existence of Lyme disease in dogs was a source of heated debate for some years, but it has now been shown to infect and cause illness in dogs. If we examine the blood of dogs who live in areas where Lyme disease is prevalent, many of the dogs show evidence of having been exposed to the disease, while very few actually come down with illness.

Lyme disease in dogs is similar to the disease in humans—fever, malaise, depression, and pain in the joints. Since many dogs have "titers" (antibodies in their blood demonstrating exposure) without having disease, Lyme disease is often diagnosed by the above symptoms and by response to a certain class of antibiotics. If caught early it can be treated easily with antibiotics. Owners who worry that their dogs are a reservoir for human infection can rest easy—there is no evidence that dogs pose a risk to humans.

The deer tick has been recognized as the most important vector of Lyme disease, but all hard ticks of the same genus can carry it. The tick needs to feast on the dog for a period of time before infection occurs, so daily tick checks are effective in preventing disease. You would do well to do the same for yourself.

There is a vaccination against Lyme disease. While many veterinarians would love to sell this to you, some veterinary immunologists feel that it is neither necessary nor efficacious. In an endemic area, it certainly wouldn't hurt, but with the tick control products available (the Preventic collar or Frontline), it shouldn't be necessary to vaccinate dogs against Lyme disease.

There is no vaccine for Rocky Mountain Spotted Fever. The signs of the disease are nonspecific: listlessness, depression, loss of appetite—the same signs that dogs show for most systemic diseases. They may have diarrhea, vomiting, discharge from the nose and eyes, coughing, and even neurologic signs. Rocky Mountain Spotted Fever can be treated with antibiotics. Because the symptoms of this disease are so general, let your veterinarian know if your dog may have been exposed to ticks.

In addition to the aforementioned diseases, ticks can also cause "tick paralysis," a loss of motor function due to a toxin emitted by some ticks. Removal of the tick is curative (sometimes supportive care is required). Avoid all tick problems by preventing ticks from attaching. Use the Preventic collar or Frontline, or spend your evenings on a tick hunt.