Pennsylvania is one of the highest-risk states in the country for tick encounters and tick-borne disease. The state accounted for 57% of all Lyme disease cases reported nationally in 2018, with over 10,000 cases that year alone. Five tick species are commonly found across the state, and understanding which ones pose the greatest threat, when they’re most active, and how to protect yourself makes a real difference in your risk.
The Five Tick Species in Pennsylvania
Two species account for more than 90% of tick identification requests submitted to Penn State: the blacklegged tick (often called the deer tick) and the American dog tick. Three others round out the list: the lone star tick, the Asian longhorned tick, and the winter tick.
The blacklegged tick is the most medically significant. It carries the bacteria that cause Lyme disease along with several other pathogens. Once limited to certain parts of the state, its range has expanded in recent years and it can now be found throughout all of Pennsylvania. These ticks prefer wooded, brushy areas and grassy edges between forests and open land.
The American dog tick is equally widespread, found across the entire state, but it favors open locations with little tree cover like grassy fields and scrubland. It’s the larger of the two common species and is the primary carrier of Rocky Mountain spotted fever in the eastern U.S.
The lone star tick has been moving northward into Pennsylvania. It’s notable for causing alpha-gal syndrome, a delayed allergic reaction to red meat and other mammalian products. When a lone star tick bites, its saliva can introduce a sugar molecule called alpha-gal into your body. Your immune system may then start treating that molecule as a threat, and the next time you eat beef, pork, or lamb, you can develop an allergic reaction, typically 2 to 6 hours after the meal. Bites from even the smallest larval stage can trigger this. Not everyone bitten will develop the allergy, but once it starts, reactions can range from hives to severe anaphylaxis.
The Asian longhorned tick is an invasive species native to East and Central Asia. It was first publicly reported in New Jersey in 2013, though it may have been present since 2010. As of 2019, only three specimens had been found in Pennsylvania, but that number is expected to grow as the tick becomes established. The winter tick, the fifth species, primarily feeds on large wildlife like deer and moose and rarely bites humans.
Why Pennsylvania Leads the Nation in Lyme Disease
Pennsylvania’s Lyme disease numbers are staggering. Between 2000 and 2018, the state recorded 106,718 confirmed cases. In 2018 specifically, Pennsylvania reported 7,920 confirmed and 2,288 probable cases out of the national total of 33,666. That means more than one in four confirmed Lyme cases in the entire country came from Pennsylvania.
The reasons are largely ecological. Pennsylvania has enormous tracts of mixed forest and suburban edge habitat, exactly the environment blacklegged ticks thrive in. The state also has a dense white-tailed deer population, which serves as a primary host for adult blacklegged ticks, and abundant white-footed mice, which are the main reservoir for the Lyme disease bacteria. Combine that with a large human population that lives, hikes, and gardens in tick territory, and the result is sustained, high transmission.
Lyme disease isn’t the only concern. Blacklegged ticks in Pennsylvania also carry pathogens that cause anaplasmosis, babesiosis, and in rare cases, Powassan virus. These illnesses can occur alongside Lyme disease as co-infections from a single bite, which can complicate symptoms and treatment.
When Ticks Are Most Active
Ticks in Pennsylvania emerge from dormancy once temperatures climb above 45°F, which can happen as early as March in milder years. The highest risk period for disease transmission is late spring through early summer, when blacklegged tick nymphs are most active. Nymphs are the life stage most likely to transmit disease because they’re tiny, roughly the size of a poppy seed, and often go completely unnoticed on the skin. They feed long enough to pass along pathogens before you ever spot them.
Adult ticks become active again in the fall, from September through November, seeking hosts before winter. Even during winter, ticks aren’t entirely gone. They enter a semi-dormant state but can become active on mild days above freezing, especially if sheltered under leaf litter or mulch. This means tick awareness in Pennsylvania is essentially a year-round concern, with the sharpest peak from May through July.
How to Protect Yourself
Repellents are your first line of defense. Products containing DEET are the most effective option. A concentration around 10% provides about two hours of protection, while 24% DEET gives roughly five hours. The maximum recommended concentration for children over two months old is 30%, and DEET should not be used on infants younger than two months. Apply it only to exposed skin, never under clothing or over cuts and wounds. Picaridin and oil of lemon eucalyptus are alternatives with effectiveness comparable to about 10% DEET.
Permethrin is a separate product meant only for clothing, not skin. You spray it on pants, socks, shoes, and gear and let it dry completely before wearing. Permethrin-treated clothing kills ticks on contact and remains effective through several washes. Combining DEET on skin with permethrin on clothing is the most protective approach available.
Beyond chemicals, practical habits help. Stick to the center of trails when hiking. Wear long pants tucked into socks in high-risk areas. Do a thorough tick check when you come indoors, paying close attention to the scalp, behind the ears, underarms, waistline, and behind the knees. Showering within two hours of being outdoors helps wash off unattached ticks.
How to Remove a Tick Properly
Use fine-pointed tweezers to grasp the tick as close to your skin as possible, right at the mouthparts. Pull steadily upward without twisting until the tick releases. Don’t yank sharply, as this can tear the mouthparts off and leave them in the skin. If that does happen, don’t panic. Embedded mouthparts alone don’t transmit Lyme disease. Never squeeze or crush the tick’s body while it’s attached, because that can force infected fluids into the bite. Skip home remedies like petroleum jelly, nail polish, or a lit match. These can irritate the tick and actually increase the chance of pathogen transmission.
After removal, wash the bite site and your hands with soap and water, then apply rubbing alcohol or antiseptic. Watch the bite site for 30 days. The signs to look for are an expanding red rash (which may or may not look like the classic bull’s-eye pattern) and flu-like symptoms such as fever, fatigue, headache, and muscle aches.
Free Tick Identification in Pennsylvania
Pennsylvania residents can get ticks identified for free through Penn State Extension. You can bring a specimen to your county Extension office, or mail it directly to the Insect Identification Laboratory at Penn State’s University Park campus. To prepare a tick for submission, place it in a small vial filled with rubbing alcohol or alcohol-based hand sanitizer, then put the vial in a plastic sandwich bag. Include your contact information and a note about where the tick was found.
Knowing the species matters because it tells you which diseases you may have been exposed to. A blacklegged tick warrants monitoring for Lyme disease symptoms, while an American dog tick carries different risks, and a lone star tick raises the possibility of alpha-gal syndrome. Identification narrows down what to watch for and helps guide any follow-up conversations about testing or treatment.