Since 2001 the Infectious Diseases Society of America (IDSA) has been recommending preventive treatment of a single dose of doxycyline for tickbites under certain narrow conditions:- The IDSA recommends preventive treatment with antibiotics only in people who meet ALL of the following criteria:
- Attached tick identified as an adult or nymphal I. scapularis (deer) tick
- Tick is estimated to have been attached for ≥36 hours (based upon how engorged the tick appears or the amount of time since outdoor exposure)
- Antibiotic treatment can begin within 72 hours of tick removal
- The local rate of tick infection with B. burgdorferi is ≥20 percent (known to occur in parts of New England, parts of the mid-Atlantic states, and parts of Minnesota and Wisconsin)
- The person can take doxycycline (eg, the person is not pregnant or breastfeeding or a child <8 years of age)
Piesman et al. have just published a new article concluding
that if the treatment is given as little as 24 hours after the bite,
only 47% of the mice were cured.
Piesman also concludes that
"Prophylactic treatment was totally ineffective when delivered ≥2days
(48hrs) after tick removal."
The IDSA recommends treating if
* Tick is estimated to have been attached for ≥36 hours (based upon
how engorged the tick appears or the amount of time since outdoor
* Antibiotic treatment can begin within 72 hours of tick removal
IDSA recommends "If the person meets ALL of the above criteria, the recommended doseof
doxycycline is a single dose of 200 mg for adults and 4 mg/kg, up to a
maximum doseof 200 mg, in children ≥ 8 years"
In 2004 Zeidner et al. noted that the "sustained release" doxy was
curative, but regular doxy only 43% effective. [Antimicrob Agents
Chemother. 2004Jul;48(7):2697-9. Sustained-release formulation of
*doxycycline* hyclate for prophylaxis of tick bite infection in a murine
model of Lyme borreliosis.]
In 2008 Dolan et al. reported on the success of 14 days of exposure to
antibiotic bait formulations..
Am J Trop Med Hyg. link 2008
A doxycycline hyclate rodent bait formulation for prophylaxis and
treatment of tick-transmitted Borrelia burgdorferi.
Dolan MC link ,
Zeidner NS link ,
Gabitzsch E link ,
Dietrich G link ,
Borchert JN link ,
Poché RM link;,
Piesman J link
The prophylacticand curative potential of doxycycline hyclate formulated
in a rodent bait at concentrations of 250 and 500 mg/Kg was evaluated in
a murine model of Lyme borreliosis. Both bait formulations
preventedtick-transmitted Borrelia burgdorferi infection in 100% of
C3H/HeJ mice (N = 16), as well as cured acute, established infection in
mice (N = 8) exposed to bait for 14 days. Spirochete infection was
cleared in 88.9% to 100% of infected nymphs feeding on mice fed 250 and
500 mg/Kg antibiotic bait formulations, respectively. These data provide
evidence for exploring alternative techniques to prevent transmission of
Lyme disease spirochetes.
This month Peisman and Hoigaard note that "prophylactic treatment was
totally ineffective when delivered ≥2days after tickremoval." [2 days =
Ticks Tick Borne Dis. link 2012 Mar 13. [Epub ahead of print]
Protective value of prophylactic antibiotic treatment of tick
bite for Lyme disease prevention: An animal model.
Piesman J link ,
Hojgaard A link .
Clinical studies have demonstrated that prophylactic antibiotic
treatment of tick bites by Ixodes scapularis in Lyme disease hyperendemic
regions in the northeastern United States can be effective in preventing
infection with Borrelia burgdorferi sensu stricto, the Lyme disease
spirochete. A large clinical trial in Westchester County, NY (USA),
demonstrated that treatment of tick bite with 200mg of oral
doxycyclinewas 87% effective in preventing Lyme disease in tick-bite
victims (Nadelman, R.B., Nowakowski, J., Fish, D., Falco, R.C., Freeman,
K., McKenna, D., Welch, P., Marcus, R., Agúero-Rosenfeld, M.E., Dennis,
D.T., Wormser, G.P., 2001. Prophylaxis with single-dose doxycyclinefor
the prevention of Lyme disease after an Ixodes scapularis tick bite. N.
Engl. J. Med. 345, 79-84.). Although this excellent clinical trial
provided much needed information, the authors enrolled subjects if the
tick bite occurred within 3days of their clinical visit, but did not
analyze the data based on the exact time between tick removal and delivery
of prophylaxis. An animal model allows for controlled experiments
designed to determine the point in time after tick bite when delivery of
oral antibiotics would be too late to prevent infection with B.
burgdorferi. Accordingly, we developed a tick-bite prophylaxis model in
mice that gave a level of prophylactic protection similar to what had
been observed in clinical trials and then varied the time post tick bite
of antibiotic delivery. We found that two treatments of
doxycycline delivered by oral gavage to mice on the day of removal of a
single potentially infectious nymphal I. scapularis protected 74% of test
mice compared to controls. When treatment was delayed until 24h after
tick removal, only 47% of mice were protected; prophylactic treatment
was totally ineffective when delivered ≥2days after tick removal.
Although the dynamics of antibiotic treatment in mice may differ from
humans, and translation of animal studies to patient management must be
approached with caution, we believe our results emphasize the point that
antibiotic prophylactic treatment of tick biteto prevent Lyme disease is
more likely to be efficacious if delivered promptly after
potentially infectious ticks are removed from patients. There is only a
very narrow window for prophylactic treatment to be effective post tick
In the past 11 years, the misinformation has spread widely on the internet. Your mission, should you choose to accept it, is to seek out sites displaying the inaccurate information and ask them to correct it. Let's see if we can turn this around before another 11 years goes by. You will be saving lives.
Thanks to Phyllis Mervine Lyme Disease.org for this information