Axenic growth in vitro of Ancylostoma duodenale to the filariform (resting) larvae.

Large numbers of free-living stages of Ancylostoma duodenale can be grown in vitro on formalin-killed Escherichia coli supplemented with cholesterol and Dulbecco's minimum essential medium (DMEN). Eggs at 28 degrees C hatched and released first-stage larvae in 24 hr. First-stage larvae molted in 36 hr. at 28 degrees C. Second-stage larvae, molted in 2-3 days at 28 degrees C, but retained the old cuticle. Third-stage larvae characterized by the presence of a buccal cap capsule; sheath; filariform esophagus and absence of lips. Lateral alae were observed in all free-living stages.