by Sally Colby
Jesse Evans, research assistant in the veterinary entomology lab at Penn State, said those who enjoy autumn outdoor activities can avoid the threat of serious disease by being smarter than the average tick.
Evans discussed arthropod vectors (any arthropods that can transmit diseases to humans) and their role in transmitting diseases to humans. The arthropods people encounter while hunting or engaging in other outdoor activities include fleas, ticks, keds (deer lice) and mosquitoes, with ticks at the top of the list for disease transmission potential.
There’s a range of tick-borne diseases, and the ticks most likely to cause problems include the lone star tick, the American dog tick and the blacklegged (deer) tick. These three ticks are responsible for transmitting diseases such as anaplasmosis, ehrlichiosis, tularemia, babesiosis, Powassan virus, alpha gal allergy, Lyme disease, bartonellosis, STARI and Rocky Mountain spotted fever.
The best way to prevent disease from ticks is to prevent tick bites. The tick life cycle begins with larvae, which is the stage at which the immature tick picks up a pathogen from a reservoir host. The disease-spreading stages of the tick are nymph and adult.
Evans breaks tick bite prevention into five steps: know before you go, dress to protect, repel, review and remove. “Tick activity changes with the season,” he said. “They’re less active in winter months, and some, like the blacklegged tick, are extremely active in fall and winter during hunting season. Lyme disease cases are seasonally variable, peaking in mid-summer. This doesn’t mean you can’t get Lyme disease in other months, nor does it mean Lyme disease pathogens are less prevalent in ticks during off months.”
Tick activity also varies throughout the day. Blacklegged ticks, which vector the pathogen that causes Lyme disease, are most active in the early morning and late evening, which is when hunters are most likely to be in the woods. Lone star ticks are most active in late morning and early afternoon. American dog ticks are most active within a certain temperature range, and are less reactive to time of day.
Dense, scrubby forests where mammals live are the most likely environments for ticks.
“When you go into the woods, stick to paths and clearings, and get as close to your chosen hunting spot as possible from the safety of a vehicle,” said Evans. “Only enter the forest when absolutely necessary, and remember fields, edges and open forests provide more protection than scrubby forests.” Avoid low brush and overhanging vegetation, which are prime habitat for ticks.
Dressing to protect is the next step in disease prevention. Evans suggested hunters “dress to suppress and dress to assess.” Dressing to suppress means wearing long sleeves, reducing the amount of exposed skin. Light-colored, plain clothing will help with visual assessment of ticks on clothing. Pants should be tucked tightly into socks and sealed with tape to create an additional barrier. Camo clothing also camouflages ticks, so solid, blaze orange clothing is helpful in more than one way.
Bird hunters tend to dress in plain clothing because birds have better eyesight than mammals and will avoid hunters in blaze orange. However, bird hunters can wear solid, light-colored clothing that suits the environment, including long sleeves and tucked-in pants, and use tick repellant.
Repelling ticks is a critical step in protecting against tick-borne illness. “Permethrin comes as a spray or dip,” said Evans. “It’s odorless and protects against ticks and mosquitoes for up to one month.” Hunters have the option of purchasing clothing that has been pre-treated with permethrin, and that treatment lasts longer than treating clothing at home. “If you elect to treat clothes yourself, you can buy a 0.5% permethrin solution as a dip or a spray,” he said. “Follow directions to treat any clothing you might wear while hunting. Be careful if you have a cat – wet permethrin can cause seizures and result in a veterinary emergency.”
DEET is the longest used and most effective broad synthetic repellant in the U.S. DEET can be used on the skin and certain clothing, has an odor and repels ticks and mosquitoes for up to five hours. “It is completely safe to use,” said Evans, “but it may harm synthetic fibers and plastics like those used in weather-resistant clothing.” A DEET product with a higher percentage of active ingredient will not be more effective than a lower percentage, but it will repel ticks for a longer time. Odor-masking DEET products are available, but haven’t been tested to determine whether they result in a more successful hunt.
Picaridin is a synthetic chemical in the piperidine family (piperidine gives black pepper its flavor). It’s odorless and non-greasy, and doesn’t damage clothing. Picaridin comes as a spray for skin and clothes, is odorless and protects against ticks and mosquitoes for up to five hours.
IR3535 is a synthetic product that’s odorless and non-greasy. It’s available as either a spray or lotion and provides much better protection against ticks than mosquitoes. It can repel mosquitoes for up to four hours and ticks for up to seven hours. Evans added that “odorless” means odorless to humans, not necessarily to wild game.
Upon returning home after a day in the woods, check clothing and skin for ticks. “Continue this investigation in the shower where the water will work to flush away unattached ticks and other ectoparasites like fleas and mites which aren’t affected by chemical repellants,” said Evans. “Ticks are small, and fit into tight, hard to reach crevices of your body.” Every part of the body should be checked thoroughly, including under the arms, the scalp, behind joints and in the groin area.
The final step in tick management is “remove.” Evans suggested removing all clothing and placing it the dryer on the high setting for five to 12 minutes to kill ticks. If no dryer is available, use a lint roller to pick up any missed ticks.
Any attached ticks should be removed with tweezers, not alcohol or Vaseline. “Grab the tick as close to the skin as you can, and pull straight up,” he said. “Do not twist. Then wash the area with soap and water. If you grab too high, you risk the tick spitting out pathogens into your body.”
After checking your body and clothing for ticks, showering and caring for clothing, there’s another step to take. Ectoparasites can remain on wild game carcasses for several days, so practice all safety measures any time you handle the carcass. Evans suggested implementing the entire five-step process each time the carcass is handled.
Some state universities provide tick pathogen identification, which is a worthwhile investment that allows timely, proactive steps that can prevent serious disease.