Interaction of Tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease, with host proteins in the kidney of Salmo trutta

For many years, brown trout (Salmo trutta fario) mortalities within the pre-alpine Isar River in Germany were reported by the Bavarian Fisheries Association (Landesfischereiverband Bayern e.V.) and local recreational anglers during August and September. Moribund fish seemed to be affected by proliferative darkening syndrome (PDS). In addition, proliferative kidney disease (PKD) caused by Tetracapsuloides bryosalmonae was discussed. To investigate this phenomenon, the present field study monitored brown trout mortalities by daily river inspection in 2017 and 2018. Moribund brown trout (n = 31) were collected and examined using histology, immunohistochemistry, qPCR, and quantitative stereology. Our investigations identified 29 (93.5%) brown trout affected by PKD. Four brown trout (12.9%) displayed combined hepatic and splenic lesions fitting the pathology of PDS. The piscine orthoreovirus 3, suspected as causative agent of PDS, was not detectable in any of the samples. Quantitative stereological analysis of the kidneys revealed a significant increase of the renal tissue volumes with interstitial inflammation and hematopoietic hyperplasia in PKD-affected fish as compared to healthy brown trout. The identified T. bryosalmonae strain was classified as part of the North American clade by phylogenetical analysis. This study highlights PKD and PDS as contributing factors to recurrent autumnal brown trout mortalities.

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Effects of oral treatment with TNP-470 on rainbow trout (Oncorhynchus mykiss) infected with Tetracapsuloides bryosalmonae (Malacosporea), the causative agent of proliferative kidney disease

Aquaculture ◽

10.1016/s0044-8486(03)00024-3 ◽

2003 ◽

Vol 221 (1-4) ◽

pp. 51-64 ◽

Cited By ~ 10

Author(s):

D.J Morris ◽

A Adams ◽

P Smith ◽

R.H Richards

Keyword(s):

Rainbow Trout ◽

Kidney Disease ◽

Oncorhynchus Mykiss ◽

Causative Agent ◽

Oral Treatment ◽

Proliferative Kidney Disease ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Tetracapsuloides Bryosalmonae

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Health Surveillance of Wild Brown Trout (Salmo trutta fario) in the Czech Republic Revealed a Coexistence of Proliferative Kidney Disease and Piscine Orthoreovirus-3 Infection

Pathogens ◽

10.3390/pathogens9080604 ◽

2020 ◽

Vol 9 (8) ◽

pp. 604 ◽

Cited By ~ 1

Author(s):

Ľubomír Pojezdal ◽

Mikolaj Adamek ◽

Eva Syrová ◽

Dieter Steinhagen ◽

Hana Minářová ◽

...

Keyword(s):

Czech Republic ◽

Kidney Disease ◽

Brown Trout ◽

Salmo Trutta ◽

Infectious Pancreatic Necrosis Virus ◽

The Czech Republic ◽

Proliferative Kidney Disease ◽

Brown Trout Salmo Trutta ◽

Tetracapsuloides Bryosalmonae ◽

Salmo Trutta Fario

The population of brown trout (Salmo trutta fario) in continental Europe is on the decline, with infectious diseases confirmed as one of the causative factors. However, no data on the epizootiological situation of wild fish in the Czech Republic are currently available. In this study, brown trout (n = 260) from eight rivers were examined for the presence of viral and parasitical pathogens. Salmonid alphavirus-2, infectious pancreatic necrosis virus, piscine novirhabdovirus (VHSV) and salmonid novirhabdovirus (IHNV) were not detected using PCR. Cell culturing showed no viruses as well, and serological analysis of 110 sera did not detect any specific antibodies against VHSV or IHNV. Fish from two rivers were positive for the presence of piscine orthoreovirus-3 (PRV-3), subtype PRV-3b. However, none of the PRV-3-positive fish showed gross pathologies typically associated with PRV infections. By far the most widespread pathogen was Tetracapsuloides bryosalmonae which was confirmed in each of the examined locations, with a prevalence of up to 65% and 100%, as established by immunohistochemistry and PCR, respectively. Furthermore, up to 43.8% of fish showed signs of proliferative kidney disease caused by T. bryosalmonae, suggesting that this parasite is a main health challenge for brown trout in the Czech Republic.

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