In the United States, the incidence of tick-borne illnesses (TBIs) is rapidly increasing, in part to better reporting, but also secondary to anthropomorphic factors such as climate change and habitat alteration. TBIs occur when a tick attaches to a human host during a blood meal, resulting in the transfer of a pathogen. TBIs lead to both localized and systemic disease in humans and can cause serious morbidity if unrecognized and untreated. In the United States, TBIs include: 1) bacterial-associated illnesses—anaplasmosis, ehrlichiosis, Lyme disease, tickborne relapsing fever, Rocky Mountain spotted fever, tularemia; 2) protozoa-associated illnesses—babesiosis; 3) viral-associated illnesses—Colorado tick fever, Powassan encephalitis; and 4) hypersensitivity-associated illnesses—alpha-gal syndrome. These TBIs have incredibly variable clinical presentations, ranging from mild viral syndromes and localized rashes to severe multisystem illnesses and progressive multistage diseases. Although accurate diagnosis and prompt treatment is important, prevention of disease transmission offers the best strategy to address TBIs in resource-limited settings. To enable frontline providers the tools for prevention and management in resource-limited settings, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines. Here we summarize the 2021 guidelines; the full text can be found at: wemjournal.org/article/S1080-6032(21)00163-0/fulltext.
The following were reviewed by the panel and specific endorsements were provided. The guidelines were specifically written for the wilderness provider and accordingly, only simple and medically relevant interventions were discussed. This is in contrast to office-based or hospital settings where laboratory testing and high-level interventions might be available.
The surest method of preventing TBIs is to prevent the vector-host interaction from ever occurring. Long-sleeved clothing may limit a tick’s ability to attach. Although light-colored clothing does not seem to reduce the number of tick bites, it does allow for greater tick visibility during tick checks (systematic scans of the body, especially of the intertriginous zones). DEET and picaridin, both commercially available, are equally efficacious tick repellants. Users of DEET should be mindful that increasing concentrations will offer greater durations of protection, but concentrations of 10% or less should be used on adolescents and should be entirely avoided in anyone under the age of two months. Picaridin may offer a superior safety profile over DEET. Other marketed repellents, such as essential oils, should not be used for primary protection due to lower efficacy or shorter duration of action. Permethrin, a repellent that is incorporated into clothing, provides synergistic protection when used in combination with DEET or picaridin.
When in tick habitat, high grasses and leaf litter should be avoided as much as possible. Walking in the middle of trails limits the possibility of brushing against ticks. Once returned from the outdoors, tick checks, in combination with bathing within two hours, are useful in preventing TBI. Bathing alone within two hours may offer some protection. Clothes should be washed and dried in high heat for at least 10 minutes to kill any ticks that may have escaped attention.