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Hikers, campers, anglers, farmers and pretty much anyone else who routinely spends time outdoors during the summer months will eventually encounter ticks. These blood-feeding parasites can be active year-round, but it’s during the warmer months that we humans are most likely to stumble through their habitats and thereby present ourselves as their next meal.
An estimated 90 species of ticks are found in the United States, most of which the average person will never see. Soft ticks in the Ornithodoros genus, for instance, are typically in caves, animal dens and rodent nests. The most likely scenario for a human being bitten by one of these species is if he or she spends a night in a rodent-infested cabin.
Other ticks are more commonly found in the spots where we’d expect them. They await a host where mammals or birds are apt to wander, including berry thickets and tall grasses. It’s a myth that ticks drop from trees onto hosts, and they’ll normally be no more than three feet off the ground, patiently waiting for a host to happen by. They’ll grab onto a passing hiker at knee level or lower and begin crawling up. They prefer to attach to areas of the body where they’re hidden, or places where clothing tightly hugs the skin: the scalp, ears, armpits, groin, waistline, ankles and the backs of knees.
Seven species of ticks are of particular concern due to their ability to transmit disease to humans:
Brown dog tick (Rhipicephalus sanguineus) is found in every state in the continental U.S.
Blacklegged tick (Ixodes scapularis), also known as a deer tick, is found in the eastern half of the country.
Western blacklegged tick (Ixodes pacificus) is found on the Pacific coast.
American dog tick (Dermacentor variabilis) is east of the Rocky Mountains and along spots of the Pacific coast.
Gulf Coast tick (Amblyomma maculatum) is found along the Atlantic coast in the southern U.S. and the Gulf of Mexico.
Lone star tick (Amblyomma americanum) resides in the southeastern and eastern U.S. The adult female is possibly the most easily recognized tick, due to the white dot in the center of her back.
Rocky Mountain wood tick (Dermacentor andersoni) is indigenous to the Rocky Mountain states at elevations above 4000 feet.
The Tick Identification Guide on TickEncounter.org can help you determine the species, life cycle stage, and seasonal activity of various tick species.
According to the Centers for Disease Control and Prevention (CDC), symptoms of many tick-borne diseases are similar, including fever, headaches, fatigue, and joint and muscle pain. There may be a rash associated with these symptoms, such as is the case with Lyme disease, Southern Tick-Associated Rash Illness (STARI), Rocky Mountain spotted fever, and rickettsiosis (which is itself another type of spotted fever).
Lyme disease gets the greatest amount of media attention of all tick-borne diseases, and for good reason. Each year, there are 30,000 cases reported to the CDC, but it’s estimated that the number of actual cases may be ten times that number. If treatment of the initial symptoms of Lyme is delayed, it will eventually spread to the heart and nervous system. Lyme disease is treated with several weeks of antibiotics. It’s only known to be spread by the blacklegged tick and the western blacklegged tick.
The lone star tick doesn’t transmit Lyme disease, but it does vector STARI with similar symptoms. The time from bite to symptoms is shorter with STARI, and patients who receive antibiotics recover more rapidly.
Chronic infections can result from Lyme and STARI, and while this isn’t true of Rocky Mountain spotted fever, there have been cases that have resulted in amputation of arms or legs, paralysis, hearing loss, and mental disability. It’s transmitted by the brown dog tick, the American dog tick, and the Rocky Mountain wood tick.
Rickettsiosis is a disease vectored by the Gulf Coast tick with symptoms similar to Rocky Mountain spotted fever, but less severe and typically with a necrotic lesion at the site of the bite.
Anaplasmosis (transmitted by blacklegged and western blacklegged ticks) and ehrlichiosis (by lone star and blacklegged ticks) are characterized by fever, chills, headaches and muscle aches. If untreated, organ failure and death can result. The antibiotic of choice for these infections is doxycycline.
Tularemia can also be treated with antibiotics, including doxycycline. Skin ulcers and swollen lymph glands are the symptoms of the most common type of tularemia. This bacterial infection can be spread by not only dog ticks, lone star ticks and wood ticks, but also via the bites of deer flies or through skin contact with an infected rabbit or rodent.
Babesiosis results when microscopic parasites are transmitted into the bloodstream via the bite of a blacklegged tick. Sometimes, the infected person exhibits no symptoms at all, but hemolytic anemia and dark urine can appear in other cases.
Yet another disease transmitted by the blacklegged tick in the northeastern U.S. and Great Lakes region is the rare Powassan virus disease, of which ten percent of cases prove fatal. Furthermore, half of those infected exhibit permanent neurological symptoms such as headaches and memory loss. Early symptoms of Powassan virus are similar to other tick-borne diseases but can advance to encephalitis and meningitis.
Heartland virus and Colorado tick fever are other conditions associated with tick bites and with similar symptoms to other tick-borne diseases. Most who are infected with these recover completely. Lone star ticks may transmit the former and Rocky Mountain wood ticks the latter.
Finally, and while not a disease per se, alpha-gal syndrome is an allergy to red meat that can result when a certain molecule is passed into the bloodstream through the bite of a lone star tick.
In 2017, the Asian longhorned tick (Haemaphysalis longicornis) was found in New Jersey and has since been confirmed in eight other eastern states. In its native range, this species is known to vector several diseases, but no specimens on U.S. soil have so far shown any pathogens. However, the Asian longhorned tick is of particular concern to livestock and pet owners due to the females’ ability to reproduce without a male, so having hundreds or even thousands of these attached to one animal isn’t unusual.
Ticks are out there, and there isn’t a lot we can do about that, so the goal should become keeping them off yourself. The ageless advice to thwart ticks with long pants and light-colored clothing remains relevant. It’s helpful to tuck pant legs into your socks, as well as to tuck in shirttails to lessen opportunities for crawling ticks to gain access to your skin.
Products containing 20 to 30 percent DEET are effective repellents, but some people are allergic to this compound. If such is the case, the active ingredient picaridin — derived from a pepper plant — may provide a safer, less-toxic alternative. One application of picaridin has been show to provide four to eight hours of protection.
Clothing can be treated with permethrin. It’s a highly-effective ingredient that can retain its potency through several washes, but shouldn’t be applied directly to the skin.
Oil of lemon eucalyptus and citronella are botanical products that may have merit as well.
A quick evaluation of the tick load on your property can be conducted with a “white flag” by attaching a three-foot-by-three-foot square of white cotton or flannel to a pole and dragging that along the grassy or brushy edges of your yard. The ticks will cling to the material and can be easily seen and removed for identification.
A blanket chemical treatment of an entire property against ticks is rarely, if ever, recommended. However, the tick load could become heavy enough to consider treating hot spots such as areas where wildlife or pets bed down. Consult with your local Cooperative Extension Service for recommendations on products approved for your area and the timing of application. Extension can also help identify ticks that you may encounter.
Ticks are an unavoidable fact of the outdoors, and while there’s no reason to lock oneself indoors during the warmer months, it pays to be wise. One’s choice of clothing can be a first step in avoiding tick bites. Understanding the types of habitats they’re attracted to will give an edge against inviting them onto one’s person, and a knowledge of products that effectively repel them will be another barrier. Take the time to learn which tick species are in your area and which illnesses are associated with these, and become familiar with the common symptoms of tick-borne diseases. Prevention is key, but if medical treatment becomes necessary, it’s important to begin that immediately.
For more resources, information, and tick distribution maps, go to CDC.gov/ticks.