Some of the creepier pests around are ticks. Ticks become active early in the spring and are one of the first biting pests we experience when the weather warms up. Ticks are a nuisance on pets as well as humans. They also can transmit diseases.
Ticks are not insects, but are close relatives of mites and spiders. In Nebraska the most common tick is the American dog tick (Dermacenter variabilis), also known as the wood tick. The American dog tick is found throughout the state. People who live in the southeastern most counties of Nebraska also may encounter the Lone Star tick, (Amblyomma americanum). As our climate warms up, we may experience more lone star ticks farther north. I found one crawling on me last year after scouting a forested area in Thurston County near the Missouri River in the northeast corner of the state. Brown dog ticks are present, as well.
Ticks have life cycles that involve four distinct states: egg, six-legged larva or seed tick, nymph, and adult. Both the American dog tick and the Lone Star tick are typical "three host" ticks. Each feeding stage (larva, nymph, and adult) of three host ticks must find and feed on a different animal.
Some people think ticks fall from trees, but this is a widespread old wives' tale. After feeding on its first host, the tick hangs onto vegetation with its hind legs and extends its front legs out from its body. Ticks are sensitive to carbon dioxide, which helps them locate hosts. The tick grabs onto its host with its front legs as the host passes by. It then climbs up the host and settles down to feed.
Rocky Mountain Spotted Fever (RMSF) disease is caused by rickettsia bacteria, Rickettsia rickettsii, and transmitted by the American dog tick. It is the most severe and most frequently reported tick-borne illness in the U.S. Although RMSF does occur in the Rocky Mountains, most cases are reported from other states. Confirmed cases of RMSF in Nebraska are very rare, but can occur.
Classic signs of RMSF are fever and rash on a person who has been bitten by a tick. The rash often starts at the extremities (wrists and ankles) and spreads toward the trunk. The rash first appears several days after the fever.Fever and rash may appear two days to two weeks after an encounter with an infected tick. In a few cases, no rash occurs at all. Early diagnosis and antibiotic treatments are important. Prompt removal of ticks from the skin greatly reduces the chance of transmission for RMSF.
Lyme disease is caused by the spirochete Borrelia burgdorferi. Lyme disease was discovered in 1976 in Connecticut, but now has been reported from most of the continental U.S. Areas of greatest incidence are the Northeast, the Atlantic seaboard, the Great Lakes states, and northern California. Early signs of Lyme disease include a red rash which expands in concentric circles outward from the tick bite producing a "bull's-eye" effect. Later, the victim may experience flu-like symptoms, such as a headache, fever, chills, lethargy, and joint and muscle pain. It is a seriously debilitating disease if ignored and untreated, but is easily treated with antibiotics in its early stages. A visit to a family doctor and blood test will determine whether a person has Lyme disease.
Very few cases of Lyme disease are reported in Nebraska. However, some health experts are unsure whether these cases are actually Lyme disease or a disease called ehrlichiosis. The reason for this uncertainty is because ticks that transmit Lyme disease (deer ticks) are not commonly found in Nebraska and the ticks present here have not been shown to vector this disease.
The Lone star tick does transmit ehrlichiosis, a disease with symptoms very similar to Lyme disease, including fever, headache, fatigue, and muscle aches. Other symptoms include nausea, vomiting, diarrhea, cough, joint pains, confusion, and, occasionally, a rash. Symptoms typically appear after an incubation period of 5-10 days following the tick bite.
A diagnosis of ehrlichiosis is based on a combination of clinical signs and symptoms, confirmed through laboratory tests. Ehrlichiosis is treatable with antibiotics when caught early. The best thing to do is reduce exposure to ticks by:
- Cultural means. Keep grassy and weedy areas trimmed to reduce harborage for tick hosts.
- Avoidance. Whenever possible, stay out of tick-infested areas like grassy pastures, prairies, and wooded areas. Restrict movement of your dog.
- Proper clothing. When entering tick infested areas, wear long-sleeved shirts and long pants. Tuck your pants into your socks so ticks cannot crawl up the inside of your pants. Wear light colored clothing. Ticks are easier to see on a light background.
- Repellents. Use an insect repellent containing the active ingredient diethyl toluamide (DEET). Apply to clothing and areas of exposed skin such as hands, wrists, ankles, and neck. Protect dogs with pour-on insecticides like Frontline, which are very effective, or flea and tick collars. Be sure to read and follow label directions.
- Inspection and removal. Conduct a body check upon return from potentially tick-infested areas by searching your entire body for ticks. Promptly remove any ticks you find.
To remove attached ticks, use the following procedure:
- Use fine-tipped tweezers.
- 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 its mouthparts to break off and remain in the skin.
- Do not squeeze, crush, or puncture the body of the tick because its fluids (saliva, hemolymph, and gut contents) may contain infectious organisms.
- After removing the tick, thoroughly disinfect the bite site and wash your hands with soap and water. If you have spent time in tick-infested areas and have flu-like symptoms later, it is advisable to get checked by your physician. RMSF, Lyme disease, and ehrlichiosis are all treatable with antibiotics if caught early.