On a trail populated by bears, wolves, poisonous snakes and maybe even cougars, the creature that scares the hell outta me is smaller than a dime!
Ixodes scapularis, aka the deer tick, aka the black legged tick - Which in turn is the most common vector for Lyme disease along with a few other equally nasty possible co-infections.
Deer ticks have three life stages - larvae, nymph, and adult. They need a blood meal between each stage. As they feed, they pick up any of several several bacterial, rickettsial, viral and protozoan diseases from their hosts, and secrete saliva and other fluids back into the host's body - along with whatever nasties they've picked up from previous hosts.
Adult females can lay as many as a couple of thousand eggs in spring. The larvea feed on small animals such as mice, then drop off to the ground where they overwinter. Around May, the larvae molts into nymphs. Which is where larger mammals, such as you and I are more likely to become potential hosts. They climb vegetation along animal trails, wait for a host to brush by, latch on and look for a suitable feeding site on the host's body. Once attached, they feed for several days till engorged. Once the nymphs feed, they drop off their hosts, and molt into adults, becoming active around October. Adults remain active all winter on days where ground and ambient temperatures are above freezing.
If summer is the worst time to pick up a tick, the place where most Appalachian Trail hikers are in the summer - from Damascus, VA, all the way to Maine - is right through the area with the highest concentration of reported Lyme cases in the country.
Lyme is notoriously hard to diagnose. Early symptoms are relatively non-specific - Fever, headache, joint pain, fatigue, depression. Sounds like the average thru-hiker... The classic sign, a characteristic circular skin rash called erythema migrans does not appear in every case. Left untreated, later symptoms may involve the joints, heart, and central nervous system. In most cases, the infection and its symptoms are eliminated by antibiotics, especially if the illness is treated early. Delayed or inadequate treatment can lead to more serious symptoms, which can be disabling and difficult to treat.
So, for those of us marching thru this war zone, prevention is the best medicine. Wear light-colored, permethrin-treated (aka Insect-Guard) clothing to make it easier to see the little monsters before they crawl in. Wear deet on exposed skin, do daily tick checks and check your sleeping bag every morning for engorged ticks that may have dropped off.
Clothing treated with permethrin is one's best defense against ticks. Clothing manufactured with permethrin bonded into the fabric is typically effective through 70 washings. If you buy permethrin from an outdoor store, and apply it yourself, it's effectiveness typically lasts 2-6 weeks, and through 6 launderings. In a typical thru hike, one would have to apply it several times. Finding it along the way might be an issue, as would mailing it. I wouldn't pack it in a drop box with food ...
Don't like the idea of spraying Deet on your body and wearing clothing impregnated with toxins - You'll like Lyme a whole lot less. Don't mess around with this. Take precautions or go hike the CDT ...
I ordered the above duds. The shirt is an ExOfficio Bugsaway Halo, and the trousers are Columbia Bug Shield Cargo Pants. I could not find the active ingredient listed on either company's web site, but the hang tags revealed that they are both manufactured by Insect Shield, LLC, and are impregnated with permethrin.
Besides ExOfficio and Columbia, Insect Shield partners with OR and White Sierra among others.
I'm hiking nobo starting in mid-March. With the mild season we've had, I'll will wear my bug shield clothing starting day one, tho one might wait till Waynesboro. If heading sobo in June/July, I'd start on day one, and certainly no later than Monson.
If you do find a deer tick attached, remove it carefully by slipping a pair of tweezers between your skin and the tick's head, and pulling it out slowly. Don't burn it with a match, or slather it with petroleum jelly, or pull it off with your fingers as those actions might cause it to regurgitate into you. Which is yucky, and could be bad. Keep the tick in a vail or baggy to be identified and tested, and see a doctor as soon as possible.