Lyme Disease - Description

Lyme disease is a vector-borne disease. A vector is an organism that carries a disease from one organism to another. In this case, the vector is the tick. The tick carries the bacterium B. burgdorferi in its blood and saliva. When the tick bites a human, it leaves some of its saliva, along with the bacterium, in the human's bloodstream. The bacterium begins to reproduce and spread. Eventually it causes the symptoms of Lyme disease.

Lyme disease accounts for about 90 percent of all reported vector-borne diseases in the United States. Nearly one hundred thousand cases of the disease were reported between 1982 and 1996. The true number of cases is difficult to estimate accurately. Some experts think that there are many more cases of the disease than are actually reported.