Life Cycle
The life cycle of T. suis is direct and does not require any intermediate host. Eggs are passed in feces from infected animals, but are single-celled and are not initially infectious. Infective J1 stage larvae develop within the shell in 3 weeks to 2 months, depending on environmental temperature. The infective J1 stage within the egg is highly resistant and can remain in this form for several years in favorable conditions. Once the infective J1 egg is ingested, the bipolar plugs are digested and the J1 larvae hatch in the small intestine and cecum. The J1 larvae penetrate the mucosa via the crypts of Lieberkühn in the distal ileum, cecum, and colon. During the next 5 weeks, the larvae undergo four molts (J2, J3, J4) to the adult stage (J5) within the mucosal layers. The adult’s thicker posterior one-third then emerges through the mucosal surface into the lumen while the thin anterior two-thirds remains embedded in the mucosal layers. Adults can be recovered anywhere from the distal ileum to the rectum, but most are located in the cecum and proximal colon. The prepatent period is 6 to 8 weeks and life span is 4 to 5 months.
Read more about this topic: Trichuris Suis
Famous quotes containing the words life and/or cycle:
“What is a life or two, Guy! Some people are better off dead. Like your wife and my father, for instance.”
—Raymond Chandler (1888–1959)
“The lifelong process of caregiving, is the ultimate link between caregivers of all ages. You and I are not just in a phase we will outgrow. This is life—birth, death, and everything in between.... The care continuum is the cycle of life turning full circle in each of our lives. And what we learn when we spoon-feed our babies will echo in our ears as we feed our parents. The point is not to be done. The point is to be ready to do again.”
—Paula C. Lowe (20th century)