Lyme disease (LD) is the most common vector-borne disease in the United States (Bratton, Edwards, Engle, Hovan, & Whiteside, 2008). The number of reported cases of LD has grown exponentially since its discovery in the 1970s. The Centers for Disease Control and Prevention (CDC) reported over 17,000 cases of LD in 2000, and by 2009 that number had risen to 38,000 (Shapiro & Gerber, 2000). Along with the increasing number of reported cases, the geographic area of ​​LD has also expanded. When LD was initially discovered, the disease was largely contained to the eastern states between Maine and Maryland and the Midwest, primarily Minnesota and Wisconsin (Alao & Decker, 2012). More recently, cases have been reported in northern California, Oregon, and even as far north as Canada and Scandinavia. Data suggest that climate change may have influenced the geographic movement and spread of Lyme disease (Bhate & Schwartz, 2011). Pathophysiology Lyme disease is acquired by the spread of the spirochete bacterium, B. burgdorferi, to its host through the bite of an infected tick, specifically of the Ixodes species (Shapiro & Gerber, 2000). The tick must attach to its host for several hours before transmission occurs. If the tick manages to feed for more than 24-36 hours, it transmits salivary secretions containing the causative bacteria to the human host (Alao & Decker, 2012). The risk of transmission becomes significant when the tick feeds for 48 hours or more (Shapiro & Gerber, 2000). Most ticks are relatively easy to spot when they are on the body. However, if the parasite moves to less easily detectable areas such as the groin, armpits or scalp, the risk of transmission increases due to the longer feeding time (Alao & Decker, 2012). Ticks… half the paper… own tick bite where the tick has been able to feed for at least 36 hours (Bhate & Schwartz, 2011). However, the use of prophylaxis has been debated due to concerns about antibiotic resistance. Works Cited Alao, OR, & Decker, C. F. (2012, June). Lyme disease. Illness per month, 58, 335-345. http://dx.doi.org/10.1016/j.disamonth.2012.03.005Bhate, C., & Schwartz, R. A. (2011, April). Lyme disease. CONTINUING MEDICAL EDUCATION, 619-636. http://dx.doi.org/10.1016/j.jaad.2010.03.047Bratton, R.L., Edwards, F.D., Engle, R.L., Hovan, M.J., & Whiteside, J.W. (2008, May). Diagnosis and treatment of Lyme disease. Mayo Clinic Proceedings, 83, 566-571. Retrieved from http://www.mayoclinicproceedings.comShapiro, ED, & Gerber, MA (2000, August). Lyme disease. Clinical Infectious Diseases, 31, 533-542. Retrieved from http://www.jstor.org/stable/4482329