Vector-Borne and Zoonotic Diseases Program

Lyme Disease

Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans by the Black-Legged Tick (Ixodes scapularis) and the Western Black-Legged Tick (Ixodes pacificus). The Black-Legged Tick (formerly called the Deer Tick) is commonly found in the northeastern states and upper Great Lakes Region of the U.S. Most human cases of Lyme disease are reported in these regions. The Western Black-Legged Tick is found in California, Oregon and Washington State. These vector tick species occur in regions of higher humidity and are non-existent in most of Arizona. The western tick vector (Ixodes pacificus) has only been found in the higher elevations of the Hualapai Mountains in Mohave County in northwest Arizona. Lyme disease is a reportable condition and has been since 1987. All suspected cases are investigated by state and/or local health officials. To date, no confirmed cases of Lyme disease have been acquired from tick bites here in Arizona. However, Arizona residents have gotten infected with this disease while traveling in other states where Lyme disease is endemic.

For more information, visit the CDC website.