Milling head worm
| Milling head worm | ||||||||||||
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Guppy female with milling head worms |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Camallanus cotti | ||||||||||||
| Fujita , 1927 |
The Fräskopfwurm , Camallanus cotti , is a nematode that infects as a parasite usually the intestinal tract of fish ( endoparasite ).
distribution
The original distribution area of Camallanus cotti is in the east and south of Asia and in Southeast Asia ; it was discovered in Japan in 1927 . Primarily through the use of some of its host fish , including the guppy ( Poecilia reticulata ), to control mosquito larvae and through the intensive trade in aquarium fish since the middle of the 20th century, it has probably achieved cosmopolitan distribution. In 1976 this species was described in Europe , 1984 in North America , 1994 in the Hawai'i Islands and 2001 in Australia .
parasite
Although it has been shown that Camallanus cotti living in aquariums can infect their ultimate host even without an intermediate host (monoxic development), copepods serve as intermediate hosts in their natural environment and thus transmit this parasite to its ultimate host (heteroxic development). This species has a facultatively heteroxous development cycle in which copepods serve as intermediate hosts and various freshwater fish, including many aquarium species, serve as final hosts. Since the probability of survival of C. cotti larvae after direct transmission is lower than with indirect transmission, it is assumed that development without an intermediate host is an adaptation to life under the extreme conditions of a closed aquarium.
Feeding water fleas or mosquito larvae that you have caught yourself from pools or ponds is one of the most common causes of its spread. In the larval stage, Camallanus cotti is absorbed by the fish and remains in the anterior area of the small intestine for some time. Here it feeds parasitically on the intestinal mucosa or epithelial tissue until its further development.
As a larva, Camallanus needs high lipid reserves , its main source of energy, to continue its growth. At this stage, the fish show no discernible abnormalities or symptoms. The further development period is several months until the fully developed worm and its migration through the intestinal tract of the fish. Camallanus cotti is also frequently found in the uterus of the female fish . Within its growth impresses Camallanus cotti from the larval stage to the mature worm by a growth rate of 100 percent.
Due to the long incubation period , it is no longer possible to determine where the infestation could have come from in the event of illness (suddenly sick fish). In the final stages of the intestinal life cycle of Camellanus cotti , it interrupts the blood supply in the intestinal mucosa with its biting tools or even breaks it through to further parasitize the body cavities. This inevitably leads to secondary infections from bacteria in the intestine, as well as bleeding into the surrounding tissue or into the anal area, which cause additional diseases in the fish and end with the death of the animal.
Male Camallanus cotti remain smaller (about 5 millimeters) than the female (about 15 millimeters). The female gives birth to live offspring ( ovoviviparous development), which is usually around 100 larvae per day. At this stage at the latest, the fish show a strongly reddened anus with clearly visible red threads hanging out and a strong emaciation. The visible red threads are an unmistakable sign of an infestation with Camellanus cotti , as this is the only intestinal parasite that is reddish and therefore clearly recognizable.
Guppy imports from Singapore or Malaysia are most commonly infected with Camallanus cotti . At the dealer you will rarely notice an infestation due to the long development time. Under certain circumstances, however, other animals are infected with Camallanus cotti here .
treatment
An infestation with the milling headworm can be treated with the antihelminthic levamisole (e.g. Concurat ® , Citarin ® , Ripercol ® ) in the form of a bath solution or by feeding with medicated live food. Levamisole has a direct cholinergic effect, in higher doses it also has an inhibitory effect on acetylcholinesterase and leads to spastic paralysis of the parasite. The active ingredient also has immune-stimulating properties in the host.
The product Nematol ® has also been on the market since 2007 . It is highly effective, does not paralyze the parasites, but kills them. The larval stages are also reached, so that only one treatment may be required. However, it is not tolerated by invertebrates , which is why treatment in the quarantine tank is recommended. It should then be noted that there are still larvae in the main tank and that it must be waited until they die due to a lack of final host. A sufficient supply of oxygen must be ensured during treatment. According to the manufacturer, thread fish , catfish , loaches and livebearers as well as juvenile fish can suffer losses in the first days of life. The agent must not be used on animals that are used for food production.
When using preparations containing glucose (e.g. Concurat ® ), a deterioration in water quality and possible wound infections ( infectious ascites ) must be taken into account due to bacterial bloom . Partial water changes must be carried out before and after treatment. Remnants of the medication are to be removed from the water by filtering through activated charcoal. Since the use of drugs has an oxygen-depleting effect, an additional administration of oxygen must be ensured during the treatment.
Web links
- PDF file with pictures of Camallanus cotti, text engl. (2.79 MB)
- (DISEASES OF AQUATIC ORGANISMS) PDF file for the investigation of parasitic infestations, Sri Lanka, text engl. (64 kB)
- Department of Zoology, University of Bergen, Norway (PDF file; 216 kB)
- Fauna Europaea taxonomy
- NCBI Taxonomy Browser ( Camallanus cotti )
swell
- Gerald Bassleer: Illustrated atlas of fish diseases in tropical ornamental fish and pond fish , ISBN 90-807831-3-7
Individual evidence
- ↑ Levsen, A. and Berland, B. 2002 Post-embryonic development of Camallanus cotti (Nematoda: Camallanidae), with emphasis on growth of some taxonomically important somatic characters Folia Parasitologica 49 (3): 231-238.
- ↑ Levsen, A. and Jakobsen, PJ 2002 Selection pressure towards monoxeny in Camallanus cotti (Nematoda, Camallanidae) facing an intermediate host bottleneck situation Parasitology 124: 625–629.
