Trichuris suis
| Trichuris suis | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Enoplea |
| Order: | Trichocephalida |
| Family: | Trichuridae |
| Genus: | Trichuris |
| Species: | T. suis |
| Binomial name | |
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Trichuris suis |
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Trichuris suis is a whipworm; the variations in thickness of the anterior and posterior segments give the parasite the characteristic “whip-like” appearance. Adult females measure 6 to 8 cm and adult males 3 to 4 cm. T. suis eggs are oval (60 × 25 μm) and yellow-brown with bipolar plugs.T. suis is also used in helminthic therapy studies.
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.
Pigs are the natural host for T. suis, but it can also affect other species - including people. Humans probably become infected with T. suis by ingesting contaminated soil or water. T. suis is found worldwide, but is most prevalent in warm, humid climates. It is rare or nonexistent in arid, very hot, or very cold regions.
In adult pigs infections with T. suis can cause diarrhea, anorexia, anemia, poor growth, dehydration, and emaciation, but acuteness is usually connected to the infective dose or concurrent bacterial enteritis. Dysentery, anemia, and death have also been described in infections in younger pigs. Critical infestations of T. suis may cause acute morbidity and mortality in young female pigs.T. suis has been shown in trials to colonize humans briefly without triggering infections.
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Wikipedia