Toxocara canis
| Toxocara canis | ||||||||||||
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adult worms |
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| Scientific name | ||||||||||||
| Toxocara canis | ||||||||||||
| ( Werner , 1782) |
Toxocara canis (German: dog roundworm ) is next to Toxascaris leonina the most common roundworm thatcan be foundin dogs . Man is a false host , that is, the larvae cannot become sexually mature. The larvae can cause clinical pictures which, depending on the localization of the infection, are referred to as larva migrans cutanea (if the skin is affected ) or as larva migrans visceralis ( digestive tract ).
The infection often goes unnoticed for months and only causes symptoms when it is mass infected . Infections in young animals are most common, and these can also be fatal. Reinfections are weaker or asymptomatic, but eggs are excreted.
Occur
The species occurs in different types of dogs, including the domestic dog , the wolf ( Canis lupus ), the golden jackal ( C. aureus ), the dingo ( C. dingo ), the coyote ( C. latrans ), the red fox (Vulpes vulpes ), the arctic fox ( V. lagopus ), and the fennec ( Megalotis zerda ). It can occur in domestic dogs as well as in wild dogs together with Toxascaris leonina as a double infection .
features
Adult worms are smooth and rounded, the body is typically roundworm-like . They reach a length of 8 to 18 cm. The eggs are thick-walled and reach a diameter of 75 µm.
Life cycle
The eggs need a ripening time of 10 to 15 days, during which time larvae 1–3 form in the egg. Dogs or rodents ingest the mature eggs with their food. Most often, mice act as paratenic hosts . They can accommodate the larvae, but no further development takes place in them.
If the dog now eats infected rodents or ingests the mature eggs, these get into the intestines. The larva 3 migrates via the portal vein (vena portae) into the liver and then into the lungs , from there they reach the lungs and trachea and are coughed up or swallowed again. The body migration takes about 10 days. During this time, the larvae molt several times 4. 25 to 30 days after infection, the adult worm develops in the small intestine from the larva ; the females produce immature eggs which are excreted through the intestines. In addition, there is the possibility of somatic migration (body migration ), especially in older, immune-competent dogs. Here, the larvae migrate to other organs (especially the skeletal muscles), are encapsulated and enter a dormant stage in which they can remain infectious for several years. During this body migration, the mammary gland can be colonized and when suckling begins, the puppies are infected via the mother's milk. Another possibility of infection for dogs is direct intestinal infection with larva 4, to which the dog's immune system does not react. Suckling bitches, who become infected when their puppies are licked, are particularly predisposed to this transplant infection . In pregnant bitches, the fetus is also affected ( intrauterine infection ); the larvae migrate via the placenta, activated chemotactically by various growth factors (especially TGF-β ), and from there into the liver of the fetuses. After the puppies are born, the larvae continue to migrate via the lungs and into the intestines.
therapy
Albendazole or mebendazole are used as antiparasitic agents to treat infections with Toxocara canis in humans .
Roundworm infestation in dogs is treated with flubendazole , fenbendazole , febantel , milbemycin oxime , pyrantel or avermectins . Especially with puppies, deworming is recommended every two weeks up to an age of twelve weeks. The active ingredients emodepside and fenbendazole can also be used to control the migrating larvae in the animal. Emodepside and selamectin can also be used to prevent transplacental transmission of the roundworm.
See also
literature
- H. Mehlhorn and G. Piekarski: Outline of parasite science. Heidelberg, 6th edition 2002.
Web links
Individual evidence
- ↑ a b A. Okulewicz, A. Perec-Matysiak, K. Buńkowska, J. Hildebrand: Toxocara canis, Toxocara cati and Toxascaris leonina in wild and domestic carnivores. Helminthica 49 (1), March 2012. doi : 10.2478 / s11687-012-0001-6 , full text
- ↑ Barbara Hinney and Anja Joachim: Gastrointestinal parasites in dogs and cats. In: Kleintierpraxis 58 (2013), pp. 256–278.
- ↑ a b Thomas Schnieder: Fighting roundworm infestation in dogs effectively - protecting people. In: Veterinärspiegel 2/2009, pp. 76-79.
- ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 294.
- ↑ J. Tänzler: Prevention of neonatal infection of puppies with Toxocara canis WERNER 1782 (Anisakidae) by treating the bitch during pregnancy. Vet Med Diss, Hanover 2004
- ↑ Payne-Johnson M, Maitland TP, Sherington J, Shanks DJ, Clements PJM et al .: Efficacy of selamectin administered topically to pregnant and lactating female dogs in the treatment and prevention of adult roundworm (Toxocara canis) infections and flea (Ctenocephalides felis felis) infestations in the dams and their pups. In: Vet. Parasitol. 91 (2000), pp. 347-358