Written by Krista Vernaleken, VMD
In a previous article on Lyme, we covered what Lyme disease is, and where in the country it exists. Now we’re going to talk about how the disease gets into the body of a human or a dog.
Lyme disease itself is harbored by the Ixodes family of ticks. However, I hear frequently from owners, “I found a tick, but it wasn’t a deer tick so it’s fine.” Well, there are other diseases transmitted by other species of ticks, so it’s not really fine. And the Ixodes ticks are tiny, especially the “baby” ticks, so your thick-furred dog may be bitten and you would never know it. I have a zero tolerance policy for ticks.
Ticks have multiple life stages, and actually only stay attached to a host for a relatively short time during each stage. They hatch from eggs into a larva (the only stage where they have six legs), eat, molt into a nymph, eat, and then molt into the adult stage. Adults mate, eat, and then drop off and lay eggs. During each phase, while eating, they are attached to the host for around 5 days.
We see spikes in ticks on pets in the spring and fall – they generally spend the summer molting and this is not an active feeding time. It is during their feeding that they become infected and pass that infection along. Small rodents (squirrels and mice, for example) are the typical hosts for the larvae. These rodents serve as a reservoir (a place that Lyme hangs out) – they are infected by a tick and remain infected, allowing subsequent tick bites to transmit the disease to new ticks. As they mature and molt, they seek out progressively larger hosts (raccoons, deer, dogs, and humans).
Time It Takes To Transmit
One important feature of Lyme disease is that it does not transmit instantly. The tick actually needs to be attached for about 36 hours for the disease to transmit. But that’s not true of all tick-borne diseases, either. There are some that can transmit in much less (6 hours) so we can’t really rest easy just because the tick was not attached for very long.
For more information on ticks, there are many great sites. We like the Companion Animal Parasite Council site.
To summarize: all ticks are of concern. We want our dogs exposed for as short a time as possible, if at all. Rodents, raccoons, and other wildlife serve as a source of Lyme disease infection for people and dogs.