Foot jiggers, also known as tungiasis, are caused by adult female sand fleas that burrow into the skin, mostly of the feet, but infestation can occur in all parts of the body. A jigger is a small parasitic flea that burrows into the skin of a warm-blooded host before laying eggs. They generally attack feet or hands. The female jigger burrows almost completely into the skin, with only its back end sticking out so it can release eggs. Once burrowed, it looks like a small black dot and typically goes unnoticed. As the females abdomen fills with blood and eggs, a bump forms underneath the skin, which is often painful and itchy and makes walking incredibly difficult. If left untreated, jiggers can lead to deadly secondary infections or even amputation. People suffering from jiggers usually attempt to remove them with safety pins, thorns, or other sharp, and often unsanitary, objects.