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

Guevara Soto M, Vaughan L, Segner H, Wahli T, Vidondo B, Schmidt-Posthaus H - Front Physiol (2016)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases and Pathobiology, Centre of Fish and Wildlife Health, 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.

No MeSH data available.


Related in: MedlinePlus

(A) Brown trout (Salmo trutta), gills, Ca. P. salmonis cysts characterized by condensed basophilic intracellular material surrounded by a clear halo; up to 20 μm in diameter. Closed arrowheads indicate edema in the subepithelial area, open arrowheads indicate scattered infiltration with mainly lymphocytes. HE, bar = 50 μm. (B) Ca. P. salmonis cysts (e.g., arrowheads), lamellae showing fusion, infiltration with lymphocytes, macrophages, and eosinophilic granular cells (open arrowheads) and subepithelial edema (arrows). HE, bar = 50 μm. (C) Ca. C. salmonicola cyst characterized by granular loosely arranged material, up to 20 μm in diameter. In the surrounding tissue only scattered edema (closed arrowheads) is visible. HE, bar = 50 μm.
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Figure 4: (A) Brown trout (Salmo trutta), gills, Ca. P. salmonis cysts characterized by condensed basophilic intracellular material surrounded by a clear halo; up to 20 μm in diameter. Closed arrowheads indicate edema in the subepithelial area, open arrowheads indicate scattered infiltration with mainly lymphocytes. HE, bar = 50 μm. (B) Ca. P. salmonis cysts (e.g., arrowheads), lamellae showing fusion, infiltration with lymphocytes, macrophages, and eosinophilic granular cells (open arrowheads) and subepithelial edema (arrows). HE, bar = 50 μm. (C) Ca. C. salmonicola cyst characterized by granular loosely arranged material, up to 20 μm in diameter. In the surrounding tissue only scattered edema (closed arrowheads) is visible. HE, bar = 50 μm.

Mentions: Two types of inclusion morphologies were identified, both leading to hypertrophy of host epithelial cells. Histologically, the first inclusion was characterized by compact dark basophilic central bacteria with formation of a clear halo around the bacterial cyst, leading to margination of the host cell nucleus (Figure 4A). This morphology is attributable to Ca. P. salmonis (type 1) (Schmidt-Posthaus et al., 2012; Guevara Soto et al., 2016). The second cyst type was histologically characterized by granular, loosely arranged basophilic bacterial material, with the host cell nucleus mostly not visible (Figure 4C), representing Ca. C. salmonicola (type 2) (Schmidt-Posthaus et al., 2012; Guevara Soto et al., 2016). Cysts of both morphologies were also present on the same gill arch identified as mixed infection (type 3). The different morphologies permit a reliable distinction between Ca. P. salmonis and Ca. C. salmonicola, and form the basis for the following analyses.


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

Guevara Soto M, Vaughan L, Segner H, Wahli T, Vidondo B, Schmidt-Posthaus H - Front Physiol (2016)

(A) Brown trout (Salmo trutta), gills, Ca. P. salmonis cysts characterized by condensed basophilic intracellular material surrounded by a clear halo; up to 20 μm in diameter. Closed arrowheads indicate edema in the subepithelial area, open arrowheads indicate scattered infiltration with mainly lymphocytes. HE, bar = 50 μm. (B) Ca. P. salmonis cysts (e.g., arrowheads), lamellae showing fusion, infiltration with lymphocytes, macrophages, and eosinophilic granular cells (open arrowheads) and subepithelial edema (arrows). HE, bar = 50 μm. (C) Ca. C. salmonicola cyst characterized by granular loosely arranged material, up to 20 μm in diameter. In the surrounding tissue only scattered edema (closed arrowheads) is visible. HE, bar = 50 μm.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4834352&req=5

Figure 4: (A) Brown trout (Salmo trutta), gills, Ca. P. salmonis cysts characterized by condensed basophilic intracellular material surrounded by a clear halo; up to 20 μm in diameter. Closed arrowheads indicate edema in the subepithelial area, open arrowheads indicate scattered infiltration with mainly lymphocytes. HE, bar = 50 μm. (B) Ca. P. salmonis cysts (e.g., arrowheads), lamellae showing fusion, infiltration with lymphocytes, macrophages, and eosinophilic granular cells (open arrowheads) and subepithelial edema (arrows). HE, bar = 50 μm. (C) Ca. C. salmonicola cyst characterized by granular loosely arranged material, up to 20 μm in diameter. In the surrounding tissue only scattered edema (closed arrowheads) is visible. HE, bar = 50 μm.
Mentions: Two types of inclusion morphologies were identified, both leading to hypertrophy of host epithelial cells. Histologically, the first inclusion was characterized by compact dark basophilic central bacteria with formation of a clear halo around the bacterial cyst, leading to margination of the host cell nucleus (Figure 4A). This morphology is attributable to Ca. P. salmonis (type 1) (Schmidt-Posthaus et al., 2012; Guevara Soto et al., 2016). The second cyst type was histologically characterized by granular, loosely arranged basophilic bacterial material, with the host cell nucleus mostly not visible (Figure 4C), representing Ca. C. salmonicola (type 2) (Schmidt-Posthaus et al., 2012; Guevara Soto et al., 2016). Cysts of both morphologies were also present on the same gill arch identified as mixed infection (type 3). The different morphologies permit a reliable distinction between Ca. P. salmonis and Ca. C. salmonicola, and form the basis for the following analyses.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases and Pathobiology, Centre of Fish and Wildlife Health, 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.

No MeSH data available.


Related in: MedlinePlus