S. stercoralis also infects humans via a mechanism called "autoinfection." Under some circumstances, such as chronic constipation, larvas produced by the parasitic females will remain in the intestinal tract long enough to develop into infective stages. Such larvas will penetrate the tissues of the intestinal tract and develop as if they had penetrated the skin. Autoinfection can also occur when larvae remain on and penetrate the perianal skin. Autoinfection often leads to very high worm loads.

Since the parasitic females live in the superficial tissues of the small intestine and can be present in high numbers, they can cause significant pathology.