page_title: Myxobolus cerebralis
section_title: Morphology
hierarchical_section_title: Myxobolus cerebralis / Morphology
caption_attribution_description: An actinomyxon spore of en:Myxobolus cerebralis. This work has been released into the public domain by its author, Anilocra. This applies worldwide. In some countries this may not be legally possible; if so: Anilocra grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law. Converted from en:Image:Actinomyxon.jpg.jpg by John Owens (talk).
context_page_description: Myxobolus cerebralis is a myxosporean parasite of salmonids that causes whirling disease in farmed salmon and trout and also in wild fish populations. It was first described in rainbow trout in Germany a century ago, but its range has spread and it has appeared in most of Europe, the United States, South Africa, Canada and other countries. In the 1980s, M. cerebralis was found to require a tubificid oligochaete to complete its life cycle. The parasite infects its hosts with its cells after piercing them with polar filaments ejected from nematocyst-like capsules.
  Whirling disease afflicts juvenile fish and causes skeletal deformation and neurological damage. Fish "whirl" forward in an awkward, corkscrew-like pattern instead of swimming normally, find feeding difficult, and are more vulnerable to predators. The mortality rate is high for fingerlings, up to 90% of infected populations, and those that do survive are deformed by the parasites residing in their cartilage and bone. They act as a reservoir for the parasite, which is released into water following the fish's death.
context_section_description: M. cerebralis has many diverse stages ranging from single cells to relatively large spores, not all of which have been studied in detail.
caption: Diagram of the structure of a triactinomyxon stage spore of Myxobolus cerebralis
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