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Reliable Field Assessment of Proliferative Kidney Disease in Wild Brown Trout, Salmo trutta, Populations: When Is the Optimal Sampling Period?
Rubin, Aurélie; Bailey, Christyn; Strepparava, Nicole; Wahli, Thomas; Segner, Helmut; Rubin, Jean-François.
Affiliation
  • Rubin A; Centre for Fish and Wildlife Health, University of Bern, 3012 Bern, Switzerland.
  • Bailey C; La Maison de la Rivière, 1131 Tolochenaz, Switzerland.
  • Strepparava N; Land, Nature, Environment Institute, University of Applied Sciences and Arts Western Switzerland, 1202 Geneva, Switzerland.
  • Wahli T; Centre for Fish and Wildlife Health, University of Bern, 3012 Bern, Switzerland.
  • Segner H; Fish Immunology and Pathology Laboratory, Animal Health Research Centre (CISA-INIA), 28130 Madrid, Spain.
  • Rubin JF; Centre for Fish and Wildlife Health, University of Bern, 3012 Bern, Switzerland.
Pathogens ; 11(6)2022 Jun 14.
Article in En | MEDLINE | ID: mdl-35745535
Proliferative kidney disease (PKD), caused by the myxozoan parasite Tetracapsuloides bryosalmonae, is suspected to contribute to the decline of wild brown trout Salmo trutta populations. Different factors need to be taken into consideration for PKD outbreaks. Among them, water temperature appears as a main driver of the disease. To understand the epidemiology and impact of the disease on wild fish populations, reliable sampling approaches to detect the presence of T. bryosalmonae-infected fish are needed. This study aimed to characterize the seasonal variation of the prevalence of T. bryosalmonae-infected fish in brown trout populations in two small streams with differing temperature regimes between upstream and downstream sites. As water temperature is known to influence PKD manifestation in brown trout, we hypothesized that the number of T. bryosalmonae-positive fish, as well as their seasonal distribution, will vary between upper and downstream parts of the two streams. Since, in field studies, results can strongly vary across years, we extended the study over a 3-year-period. The number of infected fish and the intensity of infection were assessed by histology. The results confirmed the hypothesis of pronounced temporal- and site-related differences in the percentage of PKD-positive fish and the intensity of the infection. Comparison of water temperatures (total degree days as well as the number of days with a daily mean temperature ≥15 °C) with PKD data indicated that temperature was the driving factor for the temporal development and the intensity of the infection. A mean of 1500 degree days or 30 days with a daily mean temperature ≥15 °C was required before the infection could be detected histologically. From our findings, recommendations are derived for a water temperature-driven sampling strategy campaigns that enables the detection of PKD infection and prevalence in wild brown trout populations.
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Full text: 1 Collection: 01-internacional Database: MEDLINE Type of study: Risk_factors_studies Language: En Journal: Pathogens Year: 2022 Document type: Article Affiliation country: Switzerland Country of publication: Switzerland

Full text: 1 Collection: 01-internacional Database: MEDLINE Type of study: Risk_factors_studies Language: En Journal: Pathogens Year: 2022 Document type: Article Affiliation country: Switzerland Country of publication: Switzerland