The latest Infectious Disease Society of America (IDSA) guidelines (http://www.uphs.upenn.edu/ bugdrug/antibiotic_manual/idsalyme06.pdf) agree that prophylaxis — a single dose of Doxycycline — can be given if a) the tick has been attached for at least 36 hrs, and b) the treatment is given within 72 hrs of finding the tick. (However, Lyme can be transmitted after as little as 12 hrs, and nymphal ticks, very small and easy to escape notice, only feed for 1-3 days.)

Some doctors in this area are not familiar with the latest guidelines or the high percentage of infected ticks here. If you report finding a tick and you fit within the IDSA guidelines, your doctor may still tell you to watch/wait for the rash (erythema migrans), though as many as 50% of people who get Lyme don't get a rash, and some who do don't recognize it. Occasionally a doctor will do a blood test right away, even though Lyme antibodies don't show up until several weeks to months after infection (a positive test within a week of the bite, or before actually showing any symptoms, most likely indicates an earlier infection). Others will treat you if they see a small local reaction which may not actually indicate Lyme, but will mostly give you 3 weeks of antibiotics instead of 1 dose, even if it's been less than 72 hours since the tick was found.

But even if it's 'only' 85% preventative, 1 dose of Doxycycline and a few weeks of watchfulness seems like a much better approach than many of the alternatives: the usual early-stage treatment is 2-3 weeks of Doxycycline, during which time you should not go out in the sun; treatment at later stages involves a month or more of powerful IV antibiotics. Among people I know who've been bitten there have been those treated with 3 weeks of antibiotics because of a small local reaction 1 or 2 days after a bite (probably not Lyme), and others who knew they'd been bitten but never saw a rash and eventually required IV antibiotics. Since the results of untreated Lyme can be severe, and your doctor may not be familiar with the disease, you should not only be watchful for ticks, but educated about the symptoms, diagnosis, and treatments for tick-borne illnesses.