Ticks and what to do about them
/Whitney Tilt, Conservation Chatter, June 2018.
Adult Rocky Mountain wood tick, left, and American dog tick, right. (photos by James Gathany, Centers for Disease Control and Prevention)
With warmer winters, ticks are becoming more and more abundant in the region. Generally “tick season” begins in the spring (weather-dependent) until mid-July, when warmer weather and lower humidity make ticks inactive. Many of our tick species can transmit bacterial, viral, and parasitic diseases to humans and other animals.
Ticks are arachnids (relatives of spiders, mites, and scorpions), having eight legs and no wings. Ticks might go largely unnoticed if not for their habitat of feeding on pets, livestock, wildlife, and ourselves. They are ectoparasites, living outside the host, that feed on blood as their primary nutrition. In the act of getting a blood meal, ticks are capable of transmitting several tick-borne illnesses to people including Rocky Mountain Spotted Fever and Tularemia, among others.
In general, ticks have four life stages: egg, larva, nymph, and adult. Typically, the transition for each stage is to find a host, take a blood meal, drop off the host, shed outer skin (cuticle), and grab onto a new individual, often a totally different host species – up to three different species may provide “habitat” for a single tick. However, some tick species, like the winter tick, stay on one individual through all life stages.
Ticks are attracted to the odor, heat, and breathing of animals and people. Their primary mode of “hunting” involves patiently hanging by their back legs on vegetation, along paths and game trails, for an animal or human to brush up against them. They expertly grab on to their new host and move toward a good feeding spot. Ticks have specialized mouth parts that allow them to bore into skin surfaces and extract blood and other fluids. Once attached, they produce a cement-like substance that glues them in place. In addition, their bodies are flattened so they can lie close to the skin, making it difficult to be removed by an irritated host. On humans, ticks commonly move upward toward the groin, waist area, and scalp.
Tick abundance is highly variable, depending on habitat, abundance of host animals, weather and humidity, and other factors. In Montana, tick season lasts from the onset of warmer weather in the spring until about mid-July when warmer weather and low relative humidity cause the ticks to become inactive.
Seven species of ticks are known to bite and transmit disease to people in the United States including the American dog tick (Dermacentor variabilis) and Blacklegged or deer tick (Ixodes scapularis). The Rocky Mountain wood tick (Dermacentor andersoni) is the primary disease vector in Montana. Adult Rocky Mountain wood ticks feed primarily on large mammals while the larvae and nymphs feed on rodents. Adult ticks are primarily associated with disease transmission to humans. Several other tick species are found in Montana and their distribution, unfortunately, appears to be expanding. The blacklegged ticks that are the primary vectors for Lyme disease are not known to occur in Montana at present.
Other tick species commonly target wildlife species, including rabbits, elk, and moose. Moose can be found covered with the winter or moose tick (Dermacentor albipictus). In wildlife species, ticks do no permanent harm to their hosts, but in some cases disease transmission and sheep number of ticks can cause loss of body condition or death.
Not all ticks carry disease, and not all tick bites transmit a disease to the host. But it is important to know how to avoid ticks, and what to do in the event of a tick bite. Treat any tick bite with concern (see below).
Avoiding Tick Bites
Anytime you are outdoors during the tick season, think tick avoidance:
Wear light-colored clothing to allow you to see ticks that are crawling on your clothing.
Tuck your pants legs into your socks so that ticks cannot crawl up the inside of your pants legs.
Apply repellants to discourage tick attachment.
Repellents containing permethrin can be sprayed on boots and clothing and will last for several days. Repellents containing DEET can be applied to the skin but will last only a few hours before reapplication is necessary. Use DEET with caution on children. Application of large amounts of DEET on children has been associated with adverse reactions.
Conduct a body check upon return from potentially tick-infested areas by searching your entire body for ticks. Use a hand-held or full-length mirror to view all parts of your body. Remove any tick you find on your body.
Parents should check their children for ticks, especially in the hair, when returning from potentially tick-infested areas.
Additionally, ticks may be carried into the household on clothing and pets. Both should be eamined carefully.
Removing Attached Ticks
Sooner or later you will likely find a tick on you. If it is crawling around, remove it and wash your hands. If it has become attached:
1. Use fine-tipped tweezers or notched tick extractor. Where possible, avoid removing ticks with bare hands, using a tissue, paper towel, or latex gloves.
2. Grasp the tick as close to the skin surface as possible and pull upward with steady, even pressure. Do not twist or jerk the tick; this may cause the mouthparts to break off and remain in the skin. If this happens, remove mouthparts with tweezers.
3. After removing the tick, thoroughly disinfect the bite site and wash your hands with soap and water. Do not squeeze, crush, or puncture the body of the tick because its fluids may contain infectious organisms. Skin accidentally exposed to tick fluids can be disinfected with iodine scrub, rubbing alcohol, or water containing detergents.
4. Save the tick for identification in case you become ill. This may help your doctor make an accurate diagnosis. Place the tick in a sealable plastic bag and put it in your freezer. Write the date of the bite on a piece of paper with a pencil and place it in the bag.
Consult your health care provider if you experience any signs of illness. Early detection and treatment is the best cure for any tick-borne disease.
Diseases carried by ticks in Montana.
Symptoms of tick-borne diseases vary from mild to severe infections requiring hospitalization for care, with the potential for death in rare cases. Early recognition and treatment of infection is important to decrease the risk of serious outcome. Known diseases carried by ticks in Montana are: Rocky Mountain Spotted Fever, Colorado Tick Fever, Tularemia ("rabbit fever"), and Tick-borne relapsing fever. To learn more about the diseases and their symptoms, go to http://fwp.mt.gov/recreation/safety/wildlife/ticks/diseases.html
Some Resources
About Ticks and Tick Borne Diseases, Center for Disease Control and Prevention. Tickborne Diseases of the United States.
Ticks on Companion Animals, Montana State University Extension