Common Minnesota Ticks
May 3, 2016
I hate to spoil the warm spring weather, but it’s time to talk about ticks. In Minnesota we tend to think of ticks and tick control as something to worry about seasonally or only if we and our dogs go camping or to the cabin. However, learning more about the common species of ticks found in Minnesota shows us that ticks can be found anywhere at any time of the year.
All three of our common Minnesota ticks have multiple life stages. A newly hatched tick is called a larva. After feeding on a host, the larva molts into a second stage called the nymph. After feeding again, the nymphs molt again into the final stage, adults. Some tick species prefer specific hosts at each stage while others will feed on any mammal they find.
Ticks are vectors for several diseases, meaning that they can spread the organisms that cause disease from host to host without getting sick themselves. It is usually the nymphs and adults that are responsible, as they ingest the organisms with a blood meal, but vertical passage (transmission of the disease organism from adult female directly to egg) is possible with deer ticks and lyme disease. When a tick attaches to feed, it goes through several cycles of ingesting and regurgitating its meal; this process is what moves disease causing organisms from the tick’s gut into the host.
Dermacentor variabilis (American Dog Tick, Wood Tick)
Despite its common nickname of “wood tick,” the American dog tick is actually found in grass. Attracted by the body heat of mammals, it climbs to the top of blades of grass alongside game trails and human made walking paths, including city parks and parkways. There it waits and simply grabs onto a suitable host as it walks by. This method of finding a host is called “questing.”
Between the three life stages, American Dog Ticks are active from April through September. They are known to transmit Rocky Mountain Spotted Fever, tuleremia, and possibly erlichiosis (anaplasmosis) in humans.
Ixodes scapularis (Black-legged tick, Deer tick)
The infamous deer tick is the tick most people worry about when it comes to disease. It is found primarily in areas of deciduous forests. Like American dog ticks, deer ticks are also attracted to game trails and walkways to quest, but rather than grass they wait on the tips of branches of low growing (knee high) shrubs and trees.
Even in Minnesota, deer ticks are active year round. The adult ticks are most active between October and May, and on warm winter days will tunnel upwards through snow cover to find a host. The larvae and nymphs are most active from May through September. Deer ticks can transmit lyme disease, erlichia (anaplasmosis), and babesia.
Rhipicephalus sanguineus (Brown Dog Tick)
The brown dog tick and deer tick are often mistaken for one another due to their similar adult coloring. However, the brown dog tick is larger and its mouth parts are much shorter in comparison to its body. Unlike other ticks, the brown dog tick can complete its entire life cycle indoors and can cause infestations in a home, barn, or kennel similar to flea infestations that can be very difficult to eliminate. It is often found around human settlements as its habitat is not as specialized as the American dog tick or deer tick, and will pursue its hosts instead of relying on questing.
All life stages of the brown dog tick are active year round. Although brown dog ticks rarely attach to humans, in dogs they can transmit Rocky Mountain spotted fever, erlichia (anaplasma), and babesia.
While there is a vaccine available for dogs to protect against Lyme disease specifically, the most powerful tool we have to prevent the variety of other diseases ticks can spread to our pets is the variety or topical or oral products we can use to kill ticks on our pets. Because ticks can be found in a variety of habitats (including urban/suburban) and are active year round, it is important not to forget about ticks in the winter when the cold and snow make it seem like there are none around. You can call the clinic to discuss options for tick control at any time with one of our technicians or doctors.
-Karen Christopherson DVM CVA