Pig whipworm

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Pig whipworm
Trichuris suis

Trichuris suis

Systematics
Class : Adenophorea
Subclass : Enoplia
Order : Trichocephalida
Family : Trichuridae
Genre : Whipworms ( Trichuris )
Type : Pig whipworm
Scientific name
Trichuris suis
Cabinet , 1788

The porcine whipworm ( Trichuris suis ) is an in domestic and feral pigs occurring parasite from the root of the nematodes . Like all whipworms, it is strictly host-specific and occurs worldwide.

Appearance and development cycle

Female worms are about 6–8 cm long, male worms only about half the size. The esophageal region is about half a millimeter thick and extends over the front two-thirds of the worm. The posterior end is about 0.65 mm thick and contains the midgut and genital organs.

The pig whipworm is morphologically very difficult to distinguish from the whipworm ( Trichuris trichiura ). Both types can be found in the human intestine, where the swine whipworm stops developing but can survive for several weeks. The best characteristic for differentiating between species is the length of the spicula of the male copulation apparatus. Numerous other features suggested for determination were found to be unusable or unreliable. Both types are clearly differentiated from one another on the basis of their DNA and can be differentiated using genetic tests (see DNA barcoding ).

Adult worms release eggs that are released into the outside world via the host's feces. The eggs are infectious after 4–6 weeks, this is how long the development of larva 1 takes. The eggs are sensitive to dehydration and direct sunlight, so that infections only occur in damp, shady areas. In these the eggs can remain infectious for up to 6 years. After the eggs have been taken up by the pig, the larvae 1 hatch and initially drill into the mucous membrane of the small intestine, which they leave after about 16 days. After a total of four moults in the intestinal lumen, they colonize the large intestine as adults . The prepatency is 40–50 days. Adult worms live about 5 months.

The eggs of Trichuris suis are 47–71 × 27–31 µm in size, thick-shelled and have two transparent pole plugs. The content is dark brown and unsegmented.

Infestation in pigs

The parasite attacks the large intestines of pigs and causes trichurosis (syn. Trichuriasis ). The damage to the mucous membrane caused by the worm leads to bacterial secondary infections with colic and diarrhea in the event of severe infestation . Growth disorders and anemia can occur in young animals . It is combated with anthelmintics such as mebendazole , fenbendazole , flubendazole , ivermectin or doramectin .

In wild boars from southern Germany, the parasite was found in around 30% of the animals, with young animals being more frequently affected. In a study from the Netherlands, the parasite was detected in over a third of domestic pigs in farms with outdoor enclosures and organic farms, while the prevalence in conventional pig facilities was only 11%. Sows are most commonly affected.

Use in human medicine

According to studies by the University of Iowa ( Iowa City , USA), taking swine whipworm eggs ( Trichuris suis ova ) in humans is said to have a positive effect on remission or prevention of recurrence in patients with inflammatory bowel disease . Trichuris suis was chosen because it does not survive very long in humans. The therapeutic approach is based on the assumption that the immune system, which is excessive in autoimmune diseases, would no longer attack the intestinal wall if it were given another task. However, more recent studies and meta-analyzes could not prove any positive effect in Crohn's disease .

Individual evidence

  1. ^ A b Robert J. Flynn et al .: Flynn's parasites of laboratory animals . John Wiley and Sons, 2nd ed. 2007, ISBN 9780813812021 , p. 628.
  2. ↑ C. Cutillas, R. Callejón, M. de Rojas, B. Tewes, JM Ubeda, C. Ariza, DC Guevara (2009): Trichuris suis and Trichuris trichiura are different nematode species. Acta Tropica 111: 299-307. doi : 10.1016 / j.actatropica.2009.05.011
  3. ↑ a b Hans Plonait et al .: Textbook of pig diseases . Georg Thieme Verlag, 4th edition 2004, ISBN 9783830441045 , p. 367.
  4. ↑ Johannes Eckert et al .: Textbook of Parasitology for Veterinary Medicine . Georg Thieme Verlag, 2nd edition 2008, ISBN 9783830410720 , p. 534.
  5. ↑ D. Barutzki, R. Schoierer, R. Gothe: [Helminth infections in wild boars in enclosures in southern Germany: species spectrum and infection frequency]. In: Tierärztliche Praxis Volume 18, Number 5, October 1990, pp. 529-534, ISSN  0303-6286 . PMID 2264058 .
  6. ↑ IA Eijck, FH Borgsteede: A survey of gastrointestinal parasites pig on free-range, organic and Conventional pig farms in The Netherlands. In: Veterinary research communications Volume 29, Number 5, July 2005, pp. 407-414, ISSN  1573-7446 . doi : 10.1007 / s11259-005-1201-z . PMID 16195935 .
  7. ↑ Pork tapeworms are said to calm the intestines
  8. ↑ J. Schölmerich, K. Fellermann, FW Seibold, G. Rogler, J. Langhorst, S. Howaldt, G. Novacek, AM Petersen, O. Bachmann, H. Matthes, N. Hesselbarth, N. Teich, J. Wehkamp , J. Klaus, C. Ott, K. Dilger, R. Greinwald, R. Mueller: A Randomized, Double-blind, Placebo-Controlled Trial of Trichuris suis ova in Active Crohn's Disease. In: Journal of Crohn's & colitis. Volume 11, number 4, April 2017, pp. 390-399, doi : 10.1093 / ecco-jcc / jjw184 , PMID 27707789 , PMC 5881737 (free full text).
  9. ↑ X. Huang, LR Zeng, FS Chen, JP Zhu, MH Zhu: Trichuris suis ova therapy in inflammatory bowel disease: A meta-analysis. In: Medicine. Volume 97, number 34, August 2018, p. E12087, doi : 10.1097 / MD.0000000000012087 , PMID 30142867 , PMC 6113037 (free full text) (review).