By Dr. Daniel Eubanks
April is just a couple of weeks away. With April we welcome flowers, mild breezes, the opening day of trout season and ticks! I remember the coincidence of the latter two because the second week in April I always came home with no trout and lots of ticks.
At that time, ticks weren’t much more concern than an annoyance to me. As a practicing veterinarian, however, I have become aware that ticks present a much more serious threat.
Most of God’s creatures, even the less than glamorous ones, serve some useful purpose in the great circle of life. Vultures clear away road-kill, earthworms aerate the soil and spiders eat insects. But ticks are vile, repulsive parasites that serve no apparent purpose other than to propagate themselves and transmit serious diseases in the process. They’re right up there with cockroaches.
Ticks are not insects. Adult ticks have four pairs of legs, not three pairs like insects, and therefore are classed as arachnids with spiders and mites. They have four distinct stages in their life cycle — egg, larva, nymph, adult.
In our geographic area, we have essentially just two species of ticks — the American dog tick (Dermacentor variabilis) and the deer tick (Ixoces scapularis.)
The dog tick has a one-year life cycle. It lays eggs that hatch in early spring into larvae. Larvae feed by sucking blood from wild rodents, molt into nymphs which feed again on rodents, and then molt into adult ticks. The adult then feeds on dogs or people. Adults feed, lay eggs and disappear by fall. This entire life cycle can transpire in as little as three months, so we rarely see this tick in winter.
The deer tick has a two-year life cycle. Eggs hatch in spring and the six-legged larvae feed once during the summer on rodents, especially the white-footed mouse. These larvae do not molt into nymphs until the following spring. These eight-legged nymphs feed during the second summer on mice, dogs, deer or humans before molting into adults in the fall. Adult ticks attach to a host, usually white-tailed deer, then feed and mate. The males die and the females lay their eggs in the spring. Thus at any season of the year at least two life cycle stages of this tick may be observed.
The bottom line is that nearly every tick you see in the winter time is a deer tick.
I mentioned transmitting diseases. Ticks are blood-sucking parasites that skip from host to host and are therefore big-time vectors of some serious, potentially fatal diseases. These include but are not limited to borreliosis (Lyme disease), ehrlichiosis, babesiosis, anaplasmosis and RMSF (Rocky Mountain Spotted Fever.)
In the case of Lyme disease, the spirochete bacterium Borrelia burgdorferi is ingested by the lymph stage of the tick and ultimately is transmitted by the nymph or the adult to a dog or human. The white-footed mouse is the reservoir of the bacterium that infects the larval tick, and the deer is simply the mechanical vector to transport the nymphs and adult ticks over a widespread area. Dogs and people are incidental hosts, which are susceptible to the bacterium and develop Lyme disease. The mouse and the deer are only the reservoir and the vector host, respectively, and neither is susceptible to the disease caused by the bacterium.
The other tick-borne diseases are protozoan, richettsial, etc. These are encountered less frequently than Lyme, but are not the least bit any less serious.
What defenses do we have? Tick avoidance is obvious. Either move to Colorado or stay away from tick-infested areas. Keeping ticks off of your pets is the best defense for both you and your pets against tick-borne diseases. Diligent scrutiny for ticks on dog and cat pets with manual removal should become daily routine.
Tick-picking is frequently not enough, however, and we need to get out the big ammo. Tick collars containing amitraz are useful (dogs only). “Spot-on” preparations containing fipronil (Frontline) or selamectin (Revolution) are effective on both dogs and cats. Many “over the counter” spot-ons are available, but be careful! Some of these brands have been observed to cause adverse reactions. For my money, I’ll stick to reputable research companies like Bayer (Advantage), Merck (Frontline) and Pfizer (Revolution).
Lyme vaccine has evolved through several generations into a safe and effective vaccine for use in dogs only. Merck (Merial) makes a DNA recombinant canine Lyme vaccine which is an excellent product. This immunization is recommended in our area.
Cats serve as hosts for ticks, but fortunately are not susceptible to Lyme disease. No vaccine is available or necessary for cats. But if your cat sleeps in bed with you, as my cats do, beware of ticks on your cats. You don’t want to be “Sleeping with the Enemy”!
Protect yourself and protect your pets. Ticks are more than a nuisance. They are a public health hazard. Be aware — the spring hatch is just around the corner.

