Lyme Disease – An Annual Invasion

Lyme disease

Be prepared for an invasion. Not from across the ocean, but from little critters hitching a ride on mice: ticks. Each year the territory of ticks carrying Lyme disease appears to be spreading, and urban and suburban environments are ripe for the reason they spread: mice. While traditionally people have blamed Lyme disease on deer, mice appear to play an even larger role in spreading Lyme infected ticks.

Research by ecologists has shown that the numbers of mice the previous year is correlates with the number of Lyme cases the following summer. Due to mild winters the past decade, the population of mice has increased and the range and severity of Lyme disease has increased as well.

The CDC tracks Lyme cases and the spread of Lyme has been startling. Lyme was originally confined to New England and some areas of Wisconsin. It now can be found from Maine down through Virginia, across Wisconsin and Minnesota and in smaller pockets throughout the country. The ecologists suspect this is due to larger populations of deer, increased fragmented forests (mice thrive in small patches of woodlands), decreased predators feeding upon mice and deer, and increased travel by people. DC has plenty of mice and great moue habitat: small gardens and small patches of woodlands.

Lyme is spread via an infected tick biting either you or your dog (it is possible in cats, too, but less frequent). Infected ticks carry the organism that transmits lyme, Borellia burdorferi, in their saliva and inject it into the animal while feeding. In general it takes over 24 hours for the tick to transfer Lyme to its host once it attaches. The disease is treatable in both humans and dogs, but prevention is key. For people routinely checking for ticks post any outdoor activity is key. Look in great places for a tick to hide: behind the ears, in the groin area, under the arms.

Therefore, if you note a tick on yourself or your pup, it is important to remove it as soon as possible. When removing a tick, grasp it with tweezers as close to the skin as possible and pull it off. Do not squeeze its body. Always check yourself and your dog after playing outside – simple walks in the neighborhood are sufficient to have ticks jump onto you and the pup.

For dogs, we have a three-fold method of prevention: removal of ticks, oral and topical tick preventives, and a vaccination against Lyme. The most effective preventives focus on killing ticks as soon as possible. Simparica, NexGard, and Bravecto work via causing uncontrolled neurologic issues in ticks and the ticks rapidly die. The medications have a very high affinity for the specific chemical in ticks (fleas, too), and usually cause no ill effects in dogs. When giving any of these three preventives, monitor your pup for any adverse reactions, such as vomiting, tremors, or simply not feeling well. Side effects are quite rare and pass with time. The risk from Lyme and other tick-borne disease is much greater than the risks from the preventives.

There are several Lyme vaccinations available as well. They prime the immune system to recognize the Borellia organism and mount a immune response its presence, thus decreasing the likelihood of clinical disease. Here in DC, the vaccine is recommended for most dogs.

Even with preventives and vaccination, Lyme can still be transmitted – these methods are not fool-proof. We recommend that your dog be tested for Lyme once per year as part of annual parasite testing. If positive for Lyme, treatment can help prevent problems from arising.
Tick and parasite control is complicated and requires several different paradigms. We veterinarians are here to help keep your pup (and to a degree you) safe from ticks and tick-borne diseases. As always, please let us know how we can help.

Dan Teich, DVM
District Veterinary Hospital