Scabies is caused by the parasitic mite Sarcoptes scabiei. The symptoms occur when your immune system reacts to the toxic waste left by the mites that have been digging, pooping, reproducing, and dying underneath your skin. Once your skin has been infested with the mite, it can take up to a month before you see any symptoms.
Scabies is highly contagious, and can be transmitted by any one who has at least one living mite on there skin. In order to catch scabies, you must have direct skin to skin contact with someone who already has scabies, or with something they have touched.
Commonly contaminated items that can spread scabies include, clothing, bedding, towels, and fabric toys like a teddy bear. Common activities that spread scabies include sexual intercourse, contact sports like wrestling, and massages. The most likely places to get scabies include hospitals, hotels, gyms, nail salons, schools, day cares, nursing homes, and airplanes.