Lyme disease is contagious.
A contagious disease is a subset category of transmissible diseases , which are transmitted to other persons , either by physical contact with the person suffering the disease , or by casual contact with their secretions or objects touched by them or airborne route among other routes . In the present day , most sexually transmitted diseases are considered contagious , but only some of them are subject to medical isolation . Lyme disease . The most common sign of infection is an expanding area of redness on the skin , known as erythema migrans , that begins at the site of a tick bite about a week after it has occurred . The disease does not appear to be transmissible between people , by other animals , or through food .