Life cycle of the Human Whipworm (Trichuris trichiura)

Life cycle of the Human Whipworm (Trichuris trichiura)
Photographer: Centers for Disease Control/Division of Parasitic Diseases and MalariaRights holder: Centers for Disease Control/Division of Parasitic Diseases and Malaria

The unembryonated eggs of Trichuris trichiura are passed with the host's stool (1). In the soil, the eggs develop into a 2-cell stage (2), then an advanced cleavage stage (3), and then embryonate (4). Eggs  become infective in 15 to 30 days.  After ingestion by the host (via soil-contaminated hands or food), the eggs hatch in the small intestine and release larvae (5) that mature and establish themselves as adults in the colon (6).  The adult worms (approximately 4 cm in length) live in the cecum and ascending colon.  The adult worms are fixed in that location, with the anterior portions threaded into the mucosa.  The females begin to oviposit 60 to 70 days after infection.  Female worms in the cecum shed between 3,000 and 20,000 eggs per day.  The life span of the adults is about 1 year.  Although the distribution of this parasite is worldwide, infections are more frequent in areas with tropical weather and poor sanitation practices and among children.

From Centers for Disease Control Parasites and Health website