Measles--United States, 2005.

Measles is a highly infectious, acute viral illness that can be complicated by severe pneumonia, diarrhea, and encephalitis and can result in death. In the prevaccine era, approximately 500,000 cases of measles occurred annually in the United States. During 2005, local and state health departments reported to CDC 66 confirmed cases of measles (incidence rate: less than one case per 1 million population), 34 of which were from a single outbreak in Indiana associated with infection in a traveler returning to the United States. This report describes the epidemiology of U.S. measles cases in 2005 and documents the absence of endemic measles and the continued risk for imported measles infections that can result in transmission within the United States. The findings underscore the need to maintain the highest possible measles vaccination coverage in the United States and to adhere to recommendations regarding measles vaccination.