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Biology

Causal Agent:

The nematode (roundworm) Trichuris trichiura, also called the human whipworm.

Life Cycle:

Life cycle of Trichuris trichiura

The unembryonated eggs are passed with the stool The number 1. In the soil, the eggs develop into a 2-cell stage The number 2, an advanced cleavage stage The number 3, and then they embryonate The number 4; eggs become infective in 15 to 30 days. After ingestion (soil-contaminated hands or food), the eggs hatch in the small intestine, and release larvae The number 5 that mature and establish themselves as adults in the colon The number 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.

Life cycle image and information courtesy of DPDx.

 
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  • Page last reviewed: January 10, 2013
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