Cryptobia
Cryptobia is a genus of flagellates living in the blood, in the gut or on the gills of fish. Most species are with their host in a commensal relationship, but some species also have pathogenic effects. A total of 52 species are known, of which 40 in the blood of their hosts live seven colonize the digestive system and five are found on the gills or the body surface.
The complex of diseases caused by Cryptobia is referred to by some researchers as cryptobiosis, other researchers reject this, however, since the term cryptobiosis since 1959 extremely reduced for a state metabolism is employed.
Dissemination
Cryptobia species found in the waters of Africa, Asia, Europe and North America. The majority of the species infests freshwater fish. Since the 1980s, however, it is known that Cryptobia shows a strong tolerance to salinity and salt water fish are infested.
Features
The representatives of the Cryptobia are spindle- shaped, streamlined shape. They reach a size of 12-22 microns in length and 3.5 to 4.5 micrometers in diameter. The kinetoplast is long and narrow. Go from the front end of two flagella, of which a is freely movable and serves as a shock scourge of locomotion. The other scourge runs at the cell along the rear end and protrudes beyond. Occasionally, they formed a pellicle with the undulating membrane.
Life cycle
At the gills and in the digestive tract living Cryptobia be transmitted directly from fish to fish without an intermediate host. They penetrate through the mouth into their host and anchor themselves with the rear scourge at the gill or intestinal epithelium. Propagation is by division in the longitudinal direction. Species that live in the blood of their hosts require an intermediate host of the order of the leech. The ectoparasitic species are likely to be less host-specific than their the intestine and the blood -dwelling relatives.
Harmful effect
Since there are often large amounts Crypto Bien on the gills of their hosts, it has been long time considered to be pathogenic. Recent studies show, however, that external Cryptobia not cause tissue changes. However, some blutbewohnende species can lead to high losses among infected fish:
- C. tincae caused in tench ( Tinca tinca ), the so-called flacherie
- C. salmositica occurs naturally in the blood of the silver salmon (Oncorhynchus kisutsch ) before, but causes losses in chinook salmon (Oncorhynchus tshawytscha )
- C. iubilans redeemed by encapsulation in connective and fatty tissue from severe inflammation
- C. bullocki is the cause of severe anemia in flatfish
In the 1990s, one living in the intestinal tract Cryptobia - kind caused great losses among the fishes of Lake Malawi. Affected animals died within a few days.
Treatment
For the treatment of non- specific for the production of food fish of the use of drugs on the basis of Carnidazol, furazolidone, metronidazole, Nifuratel, tinidazole or methylene blue is possible. In fish culture is the fight against intermediate hosts essential.