species requires a tubificid worm as an intermediate host, in which the spores develop into a "species" of the "genus" Triactinomyxon. These spores develop inside the oligochaete into forms which are infectious to salmonids.

Such a life cycle--with two different sexual stages, each resulting in two kinds of resistant spores--is unique amongst parasitic organisms, let alone those in the kingdom of animals. This mode of life has been confirmed in several other Myxobolus