Ichthyophthirius multifiliis
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Ichthyophthirius multifiliis |
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| Ichthyophthirius multifiliis | ||||||||||||
| Fouquet, 1876 |
Ichthyophthirius multifiliis is a globally occurring ciliate , which is considered the most dangerous unicellular parasite in fish andcausesconsiderable damage in aquacultures and aquariums . It colonizes the skin and the gills and causes ichthyophthiriosis (white spot disease). There are first reports of this disease from China as early as the 10th century. Ichthyophthirius multifiliis was originallythought to be a parasite in carp , but it affects other freshwater fish .
Ichthyophthirius multifiliis has a Lieberkühn organelle . The entire surface is covered with membrane-bound eyelashes , which enable the organism's motility . It has a vegetative macronucleus and up to four micronuclei .
Life cycle
The life cycle includes three stages, all of which are ciliate and agile: Theront , Trophont, and Tomont .
The infectious theront is elongated, approx. 40 µm long with a distinct posterior cilium. If a host in the vicinity of the Theront means penetrates Zilienschlags and a membrane structure at the front end ( Perforatum ) in the epithelium of the skin or gills. Within a few minutes, the theront differentiates itself into the trophont within the epithelium, forming a cell mouth and a vestibular apparatus. The trophont is irregular in shape and moves between the epithelial cells and in the crevices in the epithelium. It increases rapidly in size, depending on the duration of food intake to 200 to 800 µm. Depending on the ambient temperature and the host's immune status, the parasite remains in the fish for several days, usually around a week. Then he leaves the host and swims freely in the water as Tomont. After about an hour, this is attached to aquatic plants or inorganic surfaces by means of a transparent protein shell (muco cyst). In this shell, symmetrical cell divisions and a mitotic nuclear divisions take place, whereby daughter cells ( tomites ) arise. The tomites differentiate into the theronts, which pierce the cyst wall and thus get into the water.
literature
- PTK Woo: Fish Diseases and Disorders , Volume 1, CABI Publishing Series 2006, ISBN 9781845932176 , pp. 116-119.
- Harry W. Dickerson: Ichthyophthirius multifiliis , In: Patrick TK Woo, Kurt Buchmann: Fish Parasites: Pathobiology and Protection . CABI, 2012, ISBN 9781845938062 , p. 55 ff.
Individual evidence
- ↑ Kassandra E. Laila, Deanna Cho, Wei-Jen Chang: Interactions between parasitic Ciliates and their hosts: Ichthyophthirius multifiliis and cryptocaryon irritans as examples . In: Guenther Witzany, Mariusz Nowacki (Ed.): Biocommunication of Ciliates . Springer, Switzerland 2016, ISBN 978-3-319-32209-4 , pp. 327-350 .
