Cotton shrimp illness (Sporozoas)
Whitish nodules, bump-like elevations or oval to rod-shaped cysts on the skin. That is the way Dr. K.K. Vijayan describes the so-called cotton shrimp illness which also occurred at our shrimps in our domestic aquariums. These symptoms appeared at some Neocaridina denticulata and Caridina cf. zhangjiajiensis sp. "white perl" which we got from a shrimp holder that had acquired the animals approx. 6 months ago.
These oval things which we can recognize with the bare eye at the shrimp body (see picture to the left) of white pearl shrimps are Sporozoa-capsules and -cysts. These can appear microscopically small until pin-head-large. The Sporozoa capsules are caused by hundreds of the microscopic parasites in which one spore sits to the next but they are not connected with each other.
Examinations showed that the Sporozoas can also be found in the muscle tissue, however, not in such measures as in the cysts. Many Sporozoas form continuous stadiums in a cyst wrapper in inter-hosts and since the shrimps are able to survive with the Sporozoas that long we think that the shrimps serve "only" as inter-hosts for the Sporozoas.
Is the shrimp taken by a carnivorous final host for example a fish at the consumption the Sporozoas can be broadcasted to this one and infect the fish (possible final host).
Picture to the left: Sporozoa-cysts under the Carapax.
Transfer:
Since the Sporozoas are heavier than water and sink to the ground they are taken during the food search or by the consumption of already dead animals (cannibalism). Therefore you should remove dead or already infected animals from the aquarium. If a shrimp takes the Sporozoa with the feed an amoeba-similar germ slips into the intestine. This one penetrates through the intestinal wall until the musculature and forms new Sporozoas which can be recognized with the bare eye if they form visible cyst stadiums. In the later course the Sporozoas penetrate into the internal organs and lead to degeneration (disassembly) up to the solution of these what finally leads to the death of the shrimps.
Treatment:
A medical treatment is not known currently. You can attempt to prevent the infection of healthy animals by removing already infected shrimps from the basin as soon as possible.
Also dead animals should be removed from the basin since an infection through cannibalism is also possible and this should be prevented.
Picture to the left: If you crush a cyst, thousands of the microscopically small parasites get visible. 400-fold enlargement in the small picture, 1600-fold enlargement in the big picture.
Do not confuse:
A shrimp at the egg production, as seen here in the left picture with spawn base in the nape area, can easily be confused with a shrimp that is infected with Sporozoas. But differently to the healthy animal where the spawn base and the internal organs are clearly separated, the internal organs of an infected shrimp are clearly attacked and overgrown.
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