About 60 to 70 days after infection, female adults begin to release unembryonated eggs (oviposit) into the cecum at a rate of 3,000 to 20,000 eggs per day, linking the life cycle to the start. Incubation period
The exact incubation period of T. trichiura is unknown, however, immature eggs in soil under favorable conditions take about three weeks to mature: 15–30 days, 10 days minimum to mature before ideal ingestion by the human host. Favorable conditions for maturation of eggs is warm to temperate climates with adequate humidity or precipitation, as ova are resistant to cold, but not resistant to drying. Once ingested, the larva will remain dug into a villus in the small intestine for about 2–3 days until it is fully developed for migration to the ileocecal section of the gastrointestinal tract. The average total life span of T. trichiura is one year, although there have been longer cases reported, lasting as long as five years (Note: inadequate treatment and re-infection are likely to play a role in this). Morphology
Adult worms are usually 3–5 centimetres (1.2–2.0 in) long, with females being larger than males as is typical of nematodes. The thin, clear majority of the body (the anterior, whip-like end) is the esophagus, and it is the end that the worm threads into the mucosa of the colon. The widened, pinkish gray region of the body is the posterior, and it is the end that contains the parasites intestines and reproductive organs.
There has been much interest in the production of subunit vaccines against human and agricultural parasites since the early 1980s. Development of subunit vaccines requires the identification of protective antigens and their formulation with a suitable adjuvant to stimulate the immune response appropriately. References


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