A new report from the U.S. Centers for Disease Control and Prevention (CDC) showed that cases of Lyme disease have more than doubled since 1991 in the United States and the number can be underestimated.

According to the report, 2,336 cases were reported in Massachusetts in 2005, compared with 1,532 the previous year, a 50 percent increase. The number of cases rose to 23,305 from 19,804 in the same period, an 18 percent increase nationwide.

Lyme disease (Borreliosis) is a bacterial infection with a spirochete from the species complex Borrelia burgdorferi, which is most often acquired from the bite of an infected Ixodes, or black-legged, tick, also known as a deer tick.