Epitheliocystis Distribution and Characterization in Brown Trout (Salmo trutta) from the Headwaters of Two Major European Rivers, the Rhine and Rhone

Maricruz Guevara Soto; Lloyd Vaughan; Helmut Segner; Thomas Wahli; Beatriz Vidondo; Heike Schmidt-Posthaus

doi:10.3389/fphys.2016.00131

Epitheliocystis Distribution and Characterization in Brown Trout (Salmo trutta) from the Headwaters of Two Major European Rivers, the Rhine and Rhone

Front Physiol. 2016 Apr 18:7:131. doi: 10.3389/fphys.2016.00131. eCollection 2016.

Authors

Maricruz Guevara Soto¹, Lloyd Vaughan², Helmut Segner¹, Thomas Wahli¹, Beatriz Vidondo³, Heike Schmidt-Posthaus¹

Affiliations

¹ Department of Infectious Diseases and Pathobiology, Centre of Fish and Wildlife Health, University of Bern Bern, Switzerland.
² Department of Pathobiology, Institute of Veterinary Pathology, University of Zurich Zurich, Switzerland.
³ Department of Clinical Research and Veterinary Public Health, Veterinary Public Health Institute, University of Bern Bern, Switzerland.

Abstract

We present a first description of the distribution and characterization of epitheliocystis infections in brown trout (Salmo trutta) from the upper catchments of two major European rivers, the Rhine and the Rhone. Overall, epitheliocystis was widely distributed, with 70% of the Rhine and 67% of the Rhone sites harboring epitheliocystis positive brown trout. The epitheliocystis agents Candidatus Piscichlamydia salmonis and Candidatus Clavichlamydia salmonicola could be identified in both catchments, although their relative proportions differed from site to site. Additionally, in two rivers in the Rhine catchment, a new species of Candidatus Similichlamydia was identified. Based on the histology, infection intensity, and severity of pathological changes were significantly more pronounced in mixed chlamydial infections, whereas single infections showed only low numbers of cysts and mild pathology. Infections could be found over a wide range of temperatures, which showed no correlation to infection prevalence or intensity.

Keywords: Candidatus Clavichlamydia salmonicola; Candidatus Piscichlamydia salmonis; Candidatus Similichlamydia sp.; Switzerland; catchment; epitheliocystis; survey.