Transversotrema patialense
| Transversotrema patialense | ||||||||||||
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| Transversotrema patialense | ||||||||||||
| ( Soparkar , 1924) |
Transversotrema patialense is a scale worm (Transversotrematiformes) that parasitizes on fish. It is not particularly host-specific and can attack different species of fish. In the aquarium hobby, livebearers and tetras are particularlyaffected.
Appearance
The adult form of Transversotrema patialense is oval to crescent-shaped and about 1150 × 560 × 36 µm in size. The dark brown eggs are approximately 130 × 75 µm in size.
Host spectrum
The development cycle of Transversotrema patialense includes an intermediate host and a final host . Intermediate hosts are mainly freshwater snails from the family of crown snails (Thiaridae). The pond snail Radix ovata may also be infected. A wide range of freshwater fish act as ultimate hosts. Although there is no particular preference for the choice of host, the rate of reproduction fluctuates depending on the infected species.
Development cycle
Transversotrema patialense lives in its adult form under the scales of its ultimate host and feeds on its mucous membrane, tissue and blood.
The parasite produces several eggs, which are ejected before the maturation process is complete and fall to the ground. After about 2 weeks the miracidia , which are about 120 to 150 µm long and 74 to 78 µm wide, hatch . They actively swim to snails and must have found a suitable intermediate host at 25 ° C after 8 hours at the latest, otherwise they will die.
In the snail the miracidia transforms into a sporocyst , which develops into a redie . The redia forms asexual subsidiary redia and cercariae . The latter leave the Redie immature and continue to develop in the snail's tissue.
The mature cercariae leave the infested snail and swim towards the fish. They reach a speed of up to 32 body lengths per second. If a cercaria finds a suitable host, it adheres to it with a sticky secretion. The connection can be released again with another secretion. Cerarie can "crawl" around the landlord. Presumably it is looking for a conspecific already established on the host and mates with it. Then she throws off her swimming device and digs herself under a scale. The hermaphrodite animals are unlikely to practice self-fertilization.
Treatment options
If the infestation with Transversotrema patialense is low , larger fish in particular show hardly any impairment. The development of the parasite is also characterized by the swimming of false hosts, the very limited lifespan of the miracidia and the fact that ceraries themselves are often eaten by fish in search of a final host due to high losses of individuals. The mostly limited space in aquariums and the comparatively high density of intermediate and final hosts can, however, lead to a very high infestation pressure. The mucous membrane of heavily infested fish is destroyed, which can lead to death from subsequent exposure.
In aquaristics, the removal or significant reduction of intermediate hosts is a possible approach. Adult worms and ceraries can be combated with drugs based on praziquantel .
As a preventive measure, the immune system of the fish can be strengthened through optimal housing conditions. Snails can initially be kept in quarantine and only introduced into the aquarium in the second generation.
swell
literature
- Dieter Untergasser: Diseases of the aquarium fish , 2nd edition, Franckh-Kosmos Verlag, Stuttgart 2006, ISBN 3-440-10264-5
- Friedrich Lütkemöller: The Schuppenwurm, Part 1: Systematics , the Aquarium, 09/2002, Birgit Schmettkamp Verlag, ISSN 0341-2709 , pp. 64–67
- Friedrich Lütkemöller: Der Schuppenwurm, Part 2: Development cycle and morphology as well as intermediate hosts , the aquarium, 10/2002, Birgit Schmettkamp Verlag, ISSN 0341-2709 , pp. 62–66
- Friedrich Lütkemöller: The Schuppenwurm, Part 3: Evaluations of test series, infected fish and their damage as well as treatment options, preventive measures and possible routes of infection , the aquarium, 11/2002, Birgit Schmettkamp Verlag, ISSN 0341-2709 , pp. 67-71
