The “Clinical Practice Guidelines for the Prevention and Management of Tick-Borne Disease” recently published by the Wilderness Medical Society, are a good compilation of treatment suggestions but are not, in fact, new recommendations, he said. Senior author Benjamin Ho, MD, of Southern Wisconsin Emergency Associates, in Janesville, Wisconsin, admitted in an interview with Medscape Medical News.
Ho pointed out that the focus of the report was on “practitioners who practice in resource-constrained settings” and are “the group’s way of solidifying a… standard of practice” for these physicians. Ho also said that while “many recommendations are not well substantiated, the risk-benefit ratio, in our view, supports the recommendations.”
The article first reviews the different types of ticks and their distribution in the United States, the specific pathogen associated with each, the disease it causes, and comments on the seasonal variations in biting behavior. Another table shows the most common clinical syndromes, typical laboratory results, recommended diagnostic tests, and antibiotic treatments. A third section contains images of different types of ticks and photos of ticks at various stages of the life cycle and at different levels of engorgement.
The authors were careful to note: “Several tick species are capable of carrying multiple pathogens. In one study, nearly 25% of Ixodes have been co-infected with a combination of bacteria or parasites that cause Lyme disease, anaplasmosis or babesiosis. Although the diagnosis of TBI is not the subject of this [clinical practice guideline], providers should be aware of the high rates of co-infection; the presence of 1 TBI should in many cases prompt testing for others. “
In terms of recommendations for preventing tick-borne infections, the authors dispute the suggestion to wear light-colored clothing. For repellents, they recommend DEET, picaridin, and permethrin. And they also give instructions for washing clothes and removing ticks.
One recommendation is controversial: that of providing a single dose of doxycycline as prophylaxis against Lyme disease. Ho points out that this only concerned “high risk” tick bites, defined as a tick bite from a Ixodes vector species to which the tick has remained attached for at least 36 hours and which have occurred in an endemic area.
The recommendation for prophylactic doxycycline comes from an article by Robert Nadelman and colleagues in The New England Journal of Medicine and has been strongly contested by International Lyme and Associated Diseases Society (ILADS) physicians, including Daniel Cameron, MD, and others.
Sam Donta, MD, a recent member of the HHS Tick Working Group and member of the Infectious Disease Society of America (IDSA), said Medscape Medical News, “The problem with the single dose of doxycycline is that you can’t start to develop symptoms until 2 months later.” This could mask the early symptoms of Lyme. “My impression is that doxycycline – even the single dose – could have abrogated the ability to see an immune response. The idea, however, if you’ve had a tick bite, is to do nothing and wait for the symptoms develop. It gets a little more complex. But even then, you can choose to follow the patient and see him in 2 weeks, then have some blood work done. “
Donta added: “I think the screening test is inadequate. So you have to go straight to the Western blot. And you have to do both IgM and IgG” and look for specific bands.
Donta stressed that patients should be encouraged to keep any ticks attached to them and that, if possible, ticks should be sent to a reference laboratory for testing before committing a patient to a course of antibiotics. There is no harm in this short delay, he said, and most labs can identify a range of pathogens.
The Wilderness Society guidelines on tick-borne infections provide good insight for clinicians practicing in resource-limited settings and mirror those of the IDSA.
Ho and Donta do not report any relevant financial relationship.
Wilderness Environ Med. Published online October 9, 2021. Full text
Judy Stone, MD, is an infectious disease specialist and author of Resilience: One Family’s Story of Hope and Triumph Over Evil and Conducting Clinical Research, the essential guide to the subject. You can find her on drjudystone.com or on Twitter @drjudystone.
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