Short CommunicationRibosomal DNA identification of Nosema/Vairimorpha in freshwater polychaete, Manayunkia speciosa, from Oregon/California and the Laurentian Great Lakes

- Microsporidia were found in specimens of Manayunkia speciosa.
- Microsporidian isolates belong to Nosema/Vairimorpha clade.
- Infection prevalence was low.
- This is the first report of Nosema/Vairimorpha in an annelid host.

We examined Manayunkia speciosa individuals from the Klamath River, Oregon/California and Lake Erie, Michigan, USA for the presence of Microsporidia. We identified microsporidian spores and sequenced their SSU, ITS, and part of the LSU rDNA. Phylogenetic analysis of SSU rDNA indicated spores from both populations belonged to the Nosema/Vairimorpha clade. PCR showed an infection prevalence in Lake Erie M. speciosa of 0.6% (95% CI = 0.5%, 0.7%). This represents the first known example of molecularly characterized Nosema/Vairimorpha isolates infecting a non-arthropod host.