http://ohioline.osu.edu/hyg-fact/2000/2100.html
Chigger larvae do not burrow into the skin, nor suck blood. They pierce the skin and inject into the host a salivary secretion containing powerful, digestive enzymes that break down skin cells that are ingested
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Sand Fleas, Jiggers, and Chigoes - Oh My! Last week a pathologist asked for our assistance in identifying "apparent worm parts" removed from one of three skin lesions on the underside of the foot of a 19 year-old male college student returning from Argentina. The referring pathologist wondered if the "long, thin, apparent worm-like structure" extracted from the lesion represented Dracunculus medinensis (Guinea worm) or a related parasite. Upon examination, we determined the "worm" to be uncoiled uterus with eggs from the sand flea (also called jigger or chigoe), Tunga penetrans. This species is distributed throughout tropical America and Africa. The adult female burrows into the skin of humans and other mammals; at this time the flea is about 1 mm long. After mating, the female expands (with eggs) to the size of a pea. After eggs are laid and hatch, the larvae escape through a small skin aperture and develop on the ground. The presence of the sand flea in the skin often causes extreme itching, pain and often secondary infection. Tetanus and gangrene are occasional complications. http://www.health.state.mn.us/divs/dpc/ades/bugbytes/0104bb.htm