An embedded chigger and its eggs are squeezed from the skin of the foot. The chigger is a species of flea, Tunga penetrans, found in the tropical Americas and Africa. The female burrows into the skin, usually preferring sites on the soles of the feet, between the toes or, most painfully, under the toe nails. Normally only 1mm in length, the pregnant female then begins to swell, sometimes reaching 1cm across. The inflamed skin surrounding the chigger is painful and itchy. Secondary infection and ulceration may occur and tetanus or gangrene are occasional complications. Chiggers are also known as chigoe fleas, jiggers and sand fleas.