Also the number of infective juveniles may be increased by reproduction of the free-living females and males. Parasitic females anchor themselves with their mouths to the mucosa of the small intestine or burrow their anterior ends into the submucosa. Reproduction in the host is by parthenogenetic females which lay several dozen eggs a day. Eggs are released into the lumen of the gut or the submucosa where they hatch and juveniles pass into the lumen. These first-stage juveniles are 300 to 380 um long and are usually passed with the feces.
Juveniles develop either to free-livingadults or to infective filariform juveniles.
Third stage juveniles are the infective stage. They are 490 to 630 um long. This is a resting stage which does not develop further until it penetrates through skin or is ingested. Following skin penetration they are carried by the blood to the lungs, where they exit into the alveoli, travel up the trachea, are swallowed, and mature in the small intestine. If ingested, migration through the lungs is not necessary.