Clinical Presentation in Humans:
Infected persons generally remain asymptomatic for roughly one year after infection, when the mature female worm moves toward the skin and forms a painful papule (blister) in the host, typically in a lower extremity(2). Fever and often urticarial rashes accompany the blister, as well as feelings of nausea, diarrhea, vomiting and dizziness. After a few days, the blister ruptures, draining toxic fluids and thereby relieving the patient of general malaise symptoms(3). The adult worm is exposed in the ruptured blister and can then be slowly removed (see Management and Therapy). However, the open blister often develops a bacterial infection that can extend down into the tunnel occupied by the adult female(4). Later symptoms may develop including fibrosis of the skin, muscles, tendons, and joints, which may or may not interfere with locomotion and use of limbs. Many patients continue to have pain and immobile joints for up to two years after removal of the parasite.
The formation of a blister, preceding rupture (5)
Ulcer after rupture of blister. Note exposed tip of female worm emerging. (6)