A survey on Tetracapsuloides bryosalmonae infections in Slovene fresh waters

Abstract

Slovenia has no history of health problems related to proliferative kidney disease (PKD) either in farmed or in wild fish. However, due to the past molecular evidence for the presence of Tetracapsuloides bryosalmonae DNA in tissues of some fish from open waters, a survey was conducted on wild salmonids that were primarily sampled for other purposes. In winter 2010-2011, specimens from a total of 244 rainbow trout, Oncorhynchus mykiss (Walbaum), and brown trout, Salmo trutta L., from 30 bodies of fresh water were examined for T. bryosalmonae using a PCR method. The sampled fish showed no clinical signs or gross pathological lesions characteristic of PKD. Nineteen (7.8%) fish from seven (23.3%) fresh waters were positive for T. bryosalmonae. The identity of PCR amplicons was confirmed by sequencing. With one exception, all the positive fish were found in waters from the regions where the average yearly temperatures and the environmental pollution are higher. This preliminary countrywide survey provided the first insight into the situation regarding T. bryosalmonae infection of wild salmonids in Slovenia.

A survey of the distribution of the PKD‐parasite Tetracapsuloides bryosalmonae (Cnidaria: Myxozoa: Malacosporea) in salmonids in Norwegian rivers – additional information gleaned from formerly collected fish

“…; Skovgaard & Buchmann ; Dash & Vasemägi ; Jenčič et al . ), it can be expected that numerous isolates and DNA extracts are stored in many laboratories. This opens for a wide international cooperation, especially in Europe, in a project to compare the phylogenetic relationships between T. bryosalmonae isolates.…”

Distribution and prevalence of T. bryosalmonae in Austria: A first survey of trout from rivers with a shrinking population

“…Disease outbreaks and prevalence of T. bryosalmonae in wild salmonid populations have been reported from Switzerland (Wahli et al., ), the United States (Macconnell & Peterson, ), England and Wales (Feist, Peeler, Gardiner, Smith, & Longshaw, ) and Norway (Sterud et al., ). More recently, reports from Finland (Vasemägi et al., ), Denmark (Skovgaard & Buchmann, ), Norway (Mo & Jørgensen, ), Austria (Gorgoglione, Kotob, Unfer, & El‐Matbouli, ) and Slovenia (Jenčič, Zajc, Kušar, Ocepek, & Pate, ) demonstrate increased attention and a suspected spread of the disease. In this context, environmental changes, especially warmer water temperatures, are discussed to aggravate the course of PKD, thus contributing to the decline of brown trout populations (Borsuk, Reichert, Peter, Schager, & Burkhardt‐Holm, ; Okamura et al., ).…”

“…Slovenia (Jenčič, Zajc, Kušar, Ocepek, & Pate, 2014) demonstrate increased attention and a suspected spread of the disease. In this context, environmental changes, especially warmer water temperatures, are discussed to aggravate the course of PKD, thus contributing to the decline of brown trout populations (Borsuk, Reichert, Peter, Schager, & Burkhardt-Holm, 2006;Okamura et al, 2011).…”

The impact of Tetracapsuloides bryosalmonae and Myxobolus cerebralis co-infections on pathology in rainbow trout

“…PKD is currently considered an emerging disease. New outbreaks were recently described in new geographical areas such as in central Europe in Switzerland [ 12 ], Norway [ 31 ], Estonia [ 32 ], Slovenian rivers [ 33 ] and Austria [ 8 ]. More recently, a PKD outbreak has been reported in August 2016 in Montana’s Yellowstone River in the USA [ 34 ], where WD has also been reported to decrease rainbow trout population since the beginning of the twenty-first Century [ 35 – 37 ].…”