Strongyloides stercoralis (threadworm) - Fllariform larva (500 µm to 600 µm X 15

The infective filariform larva of S. stercoralis issues from the rhabditiform stage. Maturation may occur in the digestive tract, thus leading to an internal cycle of autoinfection that makes the disease perpetual. The filariform stage has a single-bulb esophagus, and a notched minute tail.