Interestingly, the disease only became apparent in 1975 when mothers of a group of children who lived near each other in Lyme, Conn., made researchers aware that their children had all been diagnosed with rheumatoid arthritis. This unusual grouping of illness that appeared "rheumatoid" eventually led researchers to the identification of the bacterial cause of the children's condition, what was then named "Lyme disease" in 1982.
The only vector for Lyme disease in the U.S. is the deer tick known as Ixodes scapularis. These ticks are carriers of the Lyme disease bacterium in their stomachs. The ticks then are vectors that can transmit the bacterium to
humans with a tick bite. The number of cases of the disease in an area depends on the number of ticks present and how often the ticks are infected with the bacteria. In certain areas of New York, where Lyme disease is common, over half of the ticks are infected. Lyme disease has been reported most often in the northeastern United States, but it has been reported in all 50 states, as well as China, Europe, Japan, Australia, and parts of the former Soviet Union. In the United States, it is primarily contracted in the Northeast in the states from Maine to Maryland, in the Midwest in Minnesota and Wisconsin, and in the West in Oregon and Northern California.