Macracanthorhynchose of the pig
The Macracanthorhynchose of the pig is a parasitosis of the wild and domestic pig , which is caused by the giant scraper ( Macracanthorhynchus hirudinaceus ). It is accordingly an acanthocephalosis , i.e. a parasitic disease caused by scratchworms (Acanthocephala).
The germ
Main article: giant scratches
The giant scraper ( Macracanthorhynchus hirudinaceus ) reaches a body length of up to 70 centimeters, whereby the females are always significantly larger than the males. As an adult it lives as an intestinal parasite in the intestines of pigs, but can also infect humans and dogs in very rare cases. Larvae of scarab beetles (Scarabaeidae) and ground beetles (Carabidae), especially May , June or rose beetles, serve as intermediate hosts .
The closely related species Macracanthorhynchus ingens , which parasitizes mainly in raccoons and foxes , on the other hand, cannot establish itself in pigs. The survival time is a maximum of two weeks and the damage is mostly only superficial.
infection
Infection with the infectious larval stages, the cystacanthene , occurs in the pasture through the ingestion of beetle larvae and beetles infected with the larvae as food (oral-alimentary infection). The grubs of the named species play an important role, although the range of species of the infected intermediate hosts varies greatly from region to region. Since the intermediate hosts are usually species with a very long development period (around four years for cockchafer), infected larvae are relevant as a pathogen depot for a very long period.
Symptoms
Infection with the giant scraper does not usually lead to recognizable symptoms in pigs, since usually only very few parasites live in a host and no further reproduction takes place there. In the case of more severe infections, especially in younger pigs, developmental disorders due to malnutrition, anemia , diarrhea , unwillingness to eat and pain reactions can appear.
In the intestine, the scratch digs deep into the muscular tissue of the small intestine , the tunica muscularis , with the help of the hooked proboscis , and gets caught there. This mechanical process leads to heavy bleeding (haemorrhages), an increase in the number of eosinophilic granulocytes in the blood to defend against parasites ( eosinophilia ) and an increase in the growth of connective tissue (connective tissue proliferation) in the area of the affected intestinal area, which is then already externally recognizable due to the button-like thickening is.
diagnosis
The diagnosis of an infestation with the giant scratcher is carried out by analyzing the pig faeces, which in infected animals contains the easily identifiable eggs of the parasite. In the case of dead pigs, the adult worm can also be found in the intestines and reliably determined.
Treatment and prevention
A targeted treatment with chemical preparations for giant scratches is hardly established and usually not necessary, since the regular infestation has neither economic nor veterinary consequences. In the event of severe infestation in young pigs, various active ingredients can be used, including multiple treatments with macrocyclic lactones such as ivermectin , in which a seven-day treatment of 0.1 to 0.2 mg per kilogram of body weight results in a loss of 86 to 100% of the Scratchworms is proven. In the case of acute peritonitis, treatment is no longer possible.
The main preventive measures that can be named are the reduction of intermediate farmers and the shift from grazing to barns; Both have led to the fact that the infestation with the giant scraper has decreased significantly in Central Europe and is now regarded as non-existent.
Epidemiology
The Macracanthorhynchose of the domestic pig is mainly found in countries and regions in which pigs are kept in open pasture. In most regions of Central Europe, in which pig farming is now practiced as intensive stables, it does not occur. Internationally, macracanthorhynchosis is a very common parasitosis.
supporting documents
Evidence cited
Most of the information in this article has been taken from the sources given under literature; the following sources are also cited:
- ↑ Survival of Macracanthorhynchus Ingens in Swine and Histopathology of Infection in Swine and Raccoons. The Journal of Parasitology 72 (2), 1986; Pages 306-314 ( abstract )
literature
- Theodor Hiepe, Renate Buchwalder, Siegfried Nickel: Textbook of Parasitology. Volume 3: Veterinary Helminthology. Gustav Fischer Verlag, Jena 1985; Pages 393-394.
- Michel Rommel, Johannes Eckert, Erich Kutzer, Wolfgang Körting, Thomas Schnieder: Veterinary Parasitology. 5th edition, Parey Buchverlag, Berlin 2000; Page 483.