Difference between revisions of "Trichuris"

Revision as of 08:34, 10 July 2010

Also known as:

whipworm

Trichuris ovis from sheep faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona

Trichuris ovis in caecum - Supplied by Biomed Image Archive

Trichuris vulpis - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine

Overview

The Trichuris worms are so called due to their characteristic whipe like structure. They have a broad posterior end tapering to a long and narrow neck which is inserted into the caecal mucosa. They have a direct life cycle, moving directly into the definitive host from the infective L1 egg stage. Once ingested the larva is freed from the egg casing and forms a mucosal nodule in which to develop before emreging into the lumen of the gastointestinal system.

Characteristics

Eggs The eggs of Trichuris species are brown in colour and are bioperculated (have a plug in each end). They are hardy eggs and in the correct coonditions can survive on pasture for up to 12 years. The Trichuris embryo develops inside the egg and is infective as the 1st larval stage living within the egg. Larvae Hatch from the egg into the small intestine and there grow and moult until the reach adulthood. Adult Attach to the mucosa of the large intesitine.

Life Cycle

The life cycle is not a standard nematode life cycle as these species are infective within the egg at a very early stage of embryo development. This means infective eggs can be present on pasture within 10 - 14 days of adult patency. Eggs are transerred to pasture in the feaces of the host animal and then ingested by animals grazing on the pasture; feaco-oral spread. Thrichuris spp. have no tissue migratory period, living there entire lives in the small and large intestine of the host.

Important Species

There are several species of veterinary importance, each typically infecting a different host species;

Trichuris vulpis; the dog whipworm
Trichuris campanula (Europe) and Trichuris serrata (North America); cat whipworms, though these are only seen rarely.
Trichuris suis; the pig whipworm

Clinical

Adult buries its thin anterior half into the intestinal mucosa and feeds on tissue secretions (not blood).
- The caecum and colon are the most commonly infected sites.
- Causes eosinophilia.
Signs may include:
- Diarrhoea
  - Catarrhal enteritis
- Anemia
- Dehydration

@@ Line 10: / Line 10: @@
 [[Image:Trichuris ovis.jpg|thumb|right|150px|''Trichuris ovis'' in caecum - Supplied by Biomed Image Archive]]
 [[Image:Trichuris vulpis.jpg|thumb|right|150px|''Trichuris vulpis'' - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
-==Overview ==ave a direct lufe cycle, moving directly into the definitive host from the infecive L1 egg stage.
+==Overview ==
-The ''Trichuris'' worms are so called due to their characteristic whipe like structure. They have a broad posterior end tapering to a long and narrow neck which is inserted into the caecal mucosa. They have a direct lufe cycle, moving directly into the definitive host from the infective L1 egg stage. Once ingested the larva is freed from the egg casing and forms a mucosal nodule in which to develop before emreging into the lumen of the gastointestinal system.
+The ''Trichuris'' worms are so called due to their characteristic whipe like structure. They have a broad posterior end tapering to a long and narrow neck which is inserted into the caecal mucosa. They have a direct life cycle, moving directly into the definitive host from the infective L1 egg stage. Once ingested the larva is freed from the egg casing and forms a mucosal nodule in which to develop before emreging into the lumen of the gastointestinal system.
-*Eggs are brown, barrel-shaped, with a plug at either end, and can survive for up to 12 years
-*The infective stage is the embryonated egg.
-*The life-cycle is direct
 ==Characteristics==
 '''Eggs'''
-The eggs of '' Trichuris species are brown in colour and are bioperculated (have a plug in each end). They are hardy eggs and in the correct coonditions can survive on pasture for up to 12 years.
+The eggs of '' Trichuris species are brown in colour and are bioperculated (have a plug in each end). They are hardy eggs and in the correct coonditions can survive on pasture for up to 12 years. The ''Trichuris'' embryo develops inside the egg and is infective as the 1st larval stage living within the egg.
 '''Larvae'''
-'''adult'''
+Hatch from the egg into the small intestine and there grow and moult until the reach adulthood.
-==Species==
+'''Adult'''
+Attach to the mucosa of the large intesitine.
-* '''''[[Trichuris vulpis]]''''' - dog whipworm
+==Life Cycle==
-* '''''Trichuris campanula''''' (Europe) and ''Trichuris serrata'' (North America) - cat whipworms.
+The life cycle is not a standard nematode life cycle as these species are infective within the egg at a very early stage of embryo development. This means infective eggs can be present on pasture within 10 - 14 days of adult patency. Eggs are transerred to pasture in the feaces of the host animal and then ingested by animals grazing on the pasture; feaco-oral spread. ''Thrichuris spp.'' have no tissue migratory period, living there entire lives in the small and large intestine of the host.
-** Are quite rare.
-* '''''[[Trichuris suis]]''''' - pig whipworm
-==Life Cycle==
+==Important Species==
+There are several species of veterinary importance, each typically infecting a different host species;
+* '''''[[Trichuris vulpis]]'''''; the dog whipworm
+* '''''Trichuris campanula''''' (Europe) and ''Trichuris serrata'' (North America); cat whipworms, though these are only seen rarely.
+* '''''[[Trichuris suis]]'''''; the pig whipworm
-* Faeco-oral spread
-* Eggs become infective after 10-14 days in soil.
-* Larvae hatch in small intestine.
-** Grow and moult.
-* Finally take up resisidence in large intestine.
-** I.e. NO tissue migratory phase.
 ==Clinical==