Myxosoma cerebralis (Myxozoa: Myxosporea) Etiologic Agent of Salmonid Whirling Disease Requires Tubificid Worm (Annelida: Oligochaeta) in its Life Cycle

Studies of the life cycle of Myxosoma cerebralis showed that development of infectivity did not occur endogenously but that the spore “aging” process required participation of an aquatic tubificid oligochaete. Data suggestive of such involvement were derived from trials in which spores were “aged” in an array of inert, sterilized, pasteurized, or natural aquatic substrates and from examination of aquatic soils from trout hatcheries in which whirling disease was epizootic. The role of the aquatic oligochaete was confirmed two ways. First, signs of whirling disease developed, and M. cerebralis spores were produced in young rainbow trout (Salmo gairdneri) that had been fed oligochaetes harvested from pond soil taken from two hatcheries where whirling disease was epizootic. Second, when containers of pasteurized soil were populated with four genera of oligochaetes–Aeolosoma, Dero, Stylaria, or Tubifex– from a biological supply house, or with tubificid worms from trout hatcheries free of whirling disease, and then seeded with M. cerebralis spores and “aged” for 4 months, whirling disease occurred only in trout held with Tubifex and with hatchery tubificids.     

Intracellular Localization of LRV1 in Infected Leishmania Cells and Epitope Conservation of the Coat Protein

ABSTRACT. Polyclonal antibodies were raised against a recombinant fragment of the coat protein of LRV1-1 to determine the epitope conservation of the coat protein among LRV1 isolates, and the intracellular localization of LRV1 particles in promastigote cells of Leishmania braziliensis . Western blot analysis showed that specific epitopes of the coat protein are highly conserved among isolates from different geographic areas. Using indirect immunofluorescence assays LRV1 viral particles were observed as fluorescent granules, limited to the cytoplasm and with no apparent association to the host organelles or the cell membrane, characteristic of a persistent, non-infectious virus.