Dear Doctor: I always use Frontline for my dog, starting in spring and ending in August. This past week, I have found several swollen ticks on my dog. Is this unusual and should I be concerned?
While there are a few different types of ticks in our area, the ones we have seen recently are the “deer” ticks. As you may know, deer ticks (a.k.a. Ixodes scapularis or the Blacklegged tick) are capable of transmitting Lyme Disease, as well as Anaplasma and Babesia. Most people are aware that deer ticks are active in spring, and tend to forget about them during the hot summer months. There is even a common belief that deer ticks hibernate during winter. In actuality, deer ticks do not hibernate, and various stages will remain active during spring, summer, fall and warm winter days (above freezing).
The adult deer tick will actually begin active feeding in fall. Ticks can be found in wooded areas and long grass, but also inhabit areas along the edge of a lawn, shrubs, leaf piles and wood piles. They do not jump, fly, nor drop from trees, but will cling to an animal as it passes by. Ticks sense the presence of animals and humans by various means, including odor, heat, moisture and vibration. The tick attaches to the host, cuts the skin, penetrates with the mouthpiece, and secretes a substance to anchor itself in place. After attachment, feeding will begin within 10 minutes to 2 hours. The presence of the tick, combined with certain enzymes, will create a local cavity where blood aggregates to feed the tick.
In spring, an adult female tick can ultimately lay 2000 to 3000 eggs. The eggs hatch into the larval form of the tick, which will attach to a mouse or various birds. After this stage of feeding, the engorged larvae drop off of the host and ultimately molt into the nymph stage. The nymph stage is most active in spring and early summer, and will eventually molt to become male or female adults. It takes two years to complete the life cycle of the tick, with the nymph and adult tick capable of disease transmission.
As you can see, one adult tick is responsible for the creation of thousands of larvae, which can ultimately transform into nymphs and adults. The nymphs and adults are most active at different times of the year, with activity also dependent on temperatures. Therefore, there is a genuine concern for tick attachment and disease transmission in early spring, summer and fall. While the risk is less in winter, it is still a concern on some days.
It is too difficult to predict when the ticks will become active in spring, and many people start their tick preventatives after they start to see ticks on their dogs or on themselves. In reality, this is already too late, as the tick has had an opportunity to attach, take a blood meal, and transmit Lyme, Anaplasma, and/or Babesia.
I personally recommend using a tick preventative all year round to avoid lapses in coverage. The reports vary, but most experts believe tick disease can be found in one third to one half of all deer ticks (one specialist believes the number approaches ninety percent). The vast majority of time when I diagnose a tick disease in a patient, there was no prior observation of an attached tick on the dog. We know the tick had to be attached to transmit disease, so this means that the client did not find the tick while it was on the dog. This is understandable given the very small size of the tick and the amount of hair on the body of the dog.
The most effective tick preventatives include collars (namely Seresto®, Scalibor® and Preventic®), topical “spot-on” (specifically Vectra 3D® and Advantix®), and oral chews (NexGard® and Bravecto®). It is important to note that Revolution® is not proven to protect against deer ticks, and fipronil-based products and essential oils have suboptimal efficacy. I would advise that you speak with your veterinarian to choose another preventative product that would be best for your dog, and commit to providing protection year round.