Cryptobia
| Cryptobia | ||||||||||||
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Trophozoit of Cryptobia helix |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Cryptobia | ||||||||||||
| Leidy , 1846 |
Cryptobia is a genus of flagellates that live in the blood, intestines, or on the gills of fish . Most species have a commensal relationshipwith their host, but some species also have pathogenic effects. A total of 52 species are known, 40 of which live in the blood of their hosts, seven colonize the digestive system and five can be found on the gills or the surface of the body.
The complex of diseases caused by Cryptobia is called cryptobiosis by some researchers, but other researchers reject this, as the term cryptobiosis has been used for a condition of extremely reduced metabolism since 1959.
distribution
Cryptobia species are found in the waters of Africa , Asia and Europe, as well as in North America . The majority of the species attack freshwater fish. However, it has been known since the 1980s that Cryptobia shows a strong tolerance with regard to salinity and that saltwater fish are also attacked.
features
The representatives of the Cryptobia are of a spindle-shaped, streamlined shape. They reach a size of 12 to 22 micrometers in length and 3.5 to 4.5 micrometers in diameter. The kinetoplast is long and narrow. Two flagella extend from the front end, one of which is free to move and serves as a whip flagellum for locomotion. The other scourge runs along the cell to the rear end and protrudes beyond it. Occasionally it forms an undulating membrane with the pellicle .
Life cycle
Cryptobia living on the gills and in the digestive tract are transmitted directly from fish to fish without an intermediate host. They penetrate their host through the mouth and anchor themselves with the posterior flagella on the epithelium of the gill or intestine . The cells multiply through longitudinal cell division. Species that live in the blood of their host require an intermediate host from the order of the leeches . The ectoparasitic species are likely to be less host specific than their gut and blood relatives.
Harmful effect
Since large amounts of Cryptobia are often found on the gills of their hosts, it was considered pathogenic for a long time. However, recent studies show that external cryptobia do not cause tissue alteration. However, some blood-dwelling species can lead to high losses among the infected fish:
- C. tincae causes so-called laziness in tench ( Tinca tinca )
- C. salmositica occurs naturally in the blood of the silver salmon ( Oncorhynchus kisutsch ), but causes losses in the king salmon ( Oncorhynchus tshawytscha )
- C. iubilans causes severe inflammation by encapsulating the connective and fatty tissue
- C. bullocki is the cause of severe anemia in flatfish
In the 1990s, a species of Cryptobia living in the intestinal tract caused great losses among the fish in Lake Malawi . Affected animals died within a few days.
treatment
Medicines based on carnidazole , dimetridazole , metronidazole , nifuratel , tinidazole or methylene blue can be used to treat fish not intended for food production . In the case of commercial fish, the control of intermediate hosts is essential.
swell
literature
- Rudolf W. Hoffmann: Fischkrankheiten , Eugen Ulmer KG, Stuttgart 2005, ISBN 3-8252-8241-4
- Dieter Untergasser: Diseases of the aquarium fish , 2nd edition, Franckh-Kosmos Verlag, Stuttgart 2006, ISBN 3-440-10264-5
- DW Bruno, B. Nowak, DG Elliott: Guide to the identification of fish protozoan and metazoan parasites in stained tissue sections , Diseases of Aquatic Organisms, Vol. 70: 1-36, 2006, ISSN 0177-5103 (Print), ISSN 1616 -1580 (online)
- Boris I. Kuperman, Victoria E. Matey, Steven B. Barlow: Flagellate Cryptobia branchialis (Bodonida: Kinetoplastida), ectoparasite of tilapia from the Salton Sea , Hydrobiologia, 473: 93-102, 2002
Individual evidence
- ↑ a b D. W. Bruno, B. Nowak, DG Elliott: Guide to the identification of fish protozoan and metazoan parasites in stained tissue sections , Diseases of Aquatic Organisms, Vol. 70: 1–36, 2006, ISSN 0177-5103 (Print) , ISSN 1616-1580 (online), page 4
- ↑ Patrick TK Woo: Cryptobiosis and its control in North American fishes , International Journal for Parasitology 2001, 31, 566-574
- ↑ KI Jönsson: On the disparate terminological use of the concept cryptobiosis , Journal of Fish Diseases, 2004, 27, 175–176
- ↑ PTK Woo: On cryptobiosis and infections by Cryptobia , Journal of Fish Diseases 2004, 27, 493-494
- ^ Rudolf W. Hoffmann: Fischkrankheiten , Eugen Ulmer KG, Stuttgart 2005, ISBN 3-8252-8241-4 , page 135