Difference between revisions of "Trichuris suis"
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{{Taxobox | {{Taxobox | ||
| − | |name =''Trichuris suis'' | + | |name =''Trichuris suis'' |
| − | |kingdom =Animalia | + | |kingdom =Animalia |
| − | |sub-kingdom = | + | |sub-kingdom = |
| − | |phylum = | + | |phylum =Nematoda |
| − | |super-class = | + | |super-class = |
| − | |class =Enopla | + | |class =Enopla |
| − | |sub-class =Dorylaimia | + | |sub-class =Dorylaimia |
| − | |super-order = | + | |super-order = |
| − | |order =Trichocephalida | + | |order =Trichocephalida |
| − | |sub-order = | + | |sub-order = |
| − | |super-family = | + | |super-family = |
| − | |family =Trichuridae | + | |family =Trichuridae |
| − | |sub-family = | + | |sub-family = |
| − | |genus = Trichuris | + | |genus =Trichuris |
| − | |species =''T. suis'' | + | |species =''T. suis'' |
}} | }} | ||
| − | + | ||
===Overview=== | ===Overview=== | ||
| − | ''Trichuris suis'' is a typical [[Trichuris|whipworm]], that primarily infects pigs and can be seen in wild boar. The predeliction site is the large intestine of the pig and the worms are only pathogenic in heavy infections. Heavy infections are rarely seen in the UK as ''T.suis'' favours warmer climates, when it is seen it is usually in pigs kept outdoors or in deep-litter systems. The | + | ''Trichuris suis'' is a typical [[Trichuris|whipworm]], that primarily infects pigs and can be seen in wild boar. The predeliction site is the large intestine of the pig and the worms are only pathogenic in heavy infections. Heavy infections are rarely seen in the UK as ''T.suis'' favours warmer climates, when it is seen it is usually in pigs kept outdoors or in deep-litter systems. The Prepatent period of the worm is 6 - 8 weeks and adults will continue to produce eggs for about 4 - 5 months. When the worm is pathogenic the primary clinical sign is haemorrhagic colitis and may facilitate the invasion of other pathogens, particularly spirochaetes. |
===Identification=== | ===Identification=== | ||
| − | The adult worms are white in colour and about 3- 5cm in length. As with other ''Trichuris'' species they have a narrow, | + | The adult worms are white in colour and about 3- 5cm in length. As with other ''Trichuris'' species they have a narrow, fillamentous anterior end becoming broader in the posterior where adult males are coiled. Males possess a single spicule within a protusible sheath though this sheath can vary in length. |
| − | The eggs are large and | + | The eggs are large and characturistically lemon shaped with plugs at both poles and appear yellow/brown in faeces. |
===Life cycle=== | ===Life cycle=== | ||
| − | The life cycle is typical of the | + | The life cycle is typical of the [[Trichuris]] worms, the embryonated egg containing the L1 larvae is infective within 1 - 2 of being passed in faeces and under suitable conditions can remain viable of a number of years. Once ingested the L1 larvae hatches and penetrates the glands of the ileum, caecum and colon where 4 moults take place before the adult worm emerges. The pre-patent period of ''T. suis'' is 6-8 weeks and the adults can survive for up to 5 months. |
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| − | + | ===Pathogenesis=== | |
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| − | + | ==== Use in Human Medicine ==== | |
| − | + | *In experimental models, ''Trichuris'' markedly increases T-regulatory activity, thereby suppressing some immune-mediated diseases (Th2 responses increased; Th1 responses decreased). | |
| − | + | *There's a theory that some human immune-mediated diseases are largely restricted to affluent developed countries (like inflammatory bowel disease and Crohn's disease) occur because the human immune system has evolved with T-regulating helminths constantly present, and therefore tends to go into overdrive in some individuals if this external regulatory influence is lacking. | |
| − | + | *This had led to the hypothesis that strictly controlled exposure of selected human patients to T. suis might ameliorate the symptoms of chronic bowel disease. | |
| + | *Large scale clinical trials (placebo-controlled cross-over studies) are currently in progress to test this hypothesis. | ||
[[Category:Trichinelloidea]] | [[Category:Trichinelloidea]] | ||
[[Category:Pig_Nematodes]] | [[Category:Pig_Nematodes]] | ||
| − | + | [[Category:To_Do_-_NickJ]] | |
| − | [[Category: | ||
Revision as of 22:07, 29 July 2010
 |
This article is still under construction. |
| Trichuris suis | |
|---|---|
| Kingdom | Animalia |
| Phylum | Nematoda |
| Class | Enopla |
| Sub-class | Dorylaimia |
| Order | Trichocephalida |
| Family | Trichuridae |
| Genus | Trichuris |
| Species | T. suis |
Overview
Trichuris suis is a typical whipworm, that primarily infects pigs and can be seen in wild boar. The predeliction site is the large intestine of the pig and the worms are only pathogenic in heavy infections. Heavy infections are rarely seen in the UK as T.suis favours warmer climates, when it is seen it is usually in pigs kept outdoors or in deep-litter systems. The Prepatent period of the worm is 6 - 8 weeks and adults will continue to produce eggs for about 4 - 5 months. When the worm is pathogenic the primary clinical sign is haemorrhagic colitis and may facilitate the invasion of other pathogens, particularly spirochaetes.
Identification
The adult worms are white in colour and about 3- 5cm in length. As with other Trichuris species they have a narrow, fillamentous anterior end becoming broader in the posterior where adult males are coiled. Males possess a single spicule within a protusible sheath though this sheath can vary in length. The eggs are large and characturistically lemon shaped with plugs at both poles and appear yellow/brown in faeces.
Life cycle
The life cycle is typical of the Trichuris worms, the embryonated egg containing the L1 larvae is infective within 1 - 2 of being passed in faeces and under suitable conditions can remain viable of a number of years. Once ingested the L1 larvae hatches and penetrates the glands of the ileum, caecum and colon where 4 moults take place before the adult worm emerges. The pre-patent period of T. suis is 6-8 weeks and the adults can survive for up to 5 months.
Pathogenesis
Use in Human Medicine
- In experimental models, Trichuris markedly increases T-regulatory activity, thereby suppressing some immune-mediated diseases (Th2 responses increased; Th1 responses decreased).
- There's a theory that some human immune-mediated diseases are largely restricted to affluent developed countries (like inflammatory bowel disease and Crohn's disease) occur because the human immune system has evolved with T-regulating helminths constantly present, and therefore tends to go into overdrive in some individuals if this external regulatory influence is lacking.
- This had led to the hypothesis that strictly controlled exposure of selected human patients to T. suis might ameliorate the symptoms of chronic bowel disease.
- Large scale clinical trials (placebo-controlled cross-over studies) are currently in progress to test this hypothesis.