Life cycle of Trichostrongylus nematodes infecting humans

Description:

Life cycle of Trichostrongylus nematodes infecting humans

Trichostrongylus eggs are passed in the stool of the definitive host (usually an herbivorous mammal) (1) and under favorable conditions (moisture, warmth, shade) larvae hatch within several days. The released rhabditiform larvae grow in the soil or on vegetation (2) and after 5 to 10 days (and two molts) they become filariform (third-stage) larvae that are infective (3). Infection of the human host occurs upon ingestion of these filariform larvae (4). The larvae reach the small intestine, where they reside and mature into adults. Adult worms inhabit the digestive tract of the definitive host and may occur as incidental infections in humans (5).

(From Centers for Disease Control Parasites and Health website)