In the western United States, that bacteria that cause Lyme disease is transmitted by the western blacklegged tick (Ixodes pacificus, female shown here). A study on the knowledge, attitudes, and practices regarding Lyme disease among physicians in California—where Lyme disease is present but less common than eastern states—shows doctors could benefit from targeted education, particularly regarding testing for Lyme disease and interpreting test results. (Photo by James Gathany, CDC Public Health Image Library)