Reservoir hosts for Gyrodactylus salaris may play a more significant role in epidemics than previously thought

G Paladini, H Hansen, CF Williams, NGH Taylor, OL Rubio-Mejia, SJ Denholm, S Hytterod, JE Bron, AP Shinn

Research output: Contribution to journalArticleResearchpeer-review

7 Citations (Scopus)

Abstract

Background: Gyrodactylus salaris Malmberg, 1957 has had a devastating impact on wild Norwegian stocks of Atlantic salmon Salmo salar L., and it is the only Office International des Epizooties (OIE) listed parasitic pathogen of fish. The UK is presently recognised as G. salaris-free, and management plans for its containment and control are currently based on Scandinavian studies. The current study investigates the susceptibility of British salmonids to G. salaris, and determines whether, given the host isolation since the last glaciation and potential genetic differences, the populations under test would exhibit different levels of susceptibility, as illustrated by the parasite infection trajectory over time, from their Scandinavian counterparts. Methods: Populations of S. salar, brown trout Salmo trutta L., and grayling Thymallus thymallus (L.), raised from wild stock in UK government hatcheries, were flown to Norway and experimentally challenged with a known pathogenic strain of G. salaris. Each fish was lightly anaesthetised and marked with a unique tattoo for individual parasite counting. A single Norwegian population of S. salar from the River Lærdalselva was used as a control. Parasite numbers were assessed every seven days until day 48 and then every 14 days. Results: Gyrodactylus salaris regularly leads to high mortalities on infected juveniles S. salar. The number of G. salaris on British S. salar rose exponentially until the experiment was terminated at 33 days due to fish welfare concerns. The numbers of parasites on S. trutta and T. thymallus increased sharply, reaching a peak of infection on days 12 and 19 post-infection respectively, before declining to a constant low level of infection until the termination of the experiment at 110 days. Conclusions: The ability of S. trutta and T. thymallus to carry an infection for long periods increases the window of exposure for these two hosts and the potential transfer of G. salaris to other susceptible hosts. This study demonstrates that G. salaris can persist on S. trutta for longer periods than previously thought, and that the role that S. trutta could play in disseminating G. salaris needs to be considered carefully and factored into management plans and epidemics across Europe.
Original languageEnglish
Pages (from-to)7 - 5
Number of pages1
JournalParasites Vectors
Volume7
Issue number1
DOIs
Publication statusFirst published - 20 Dec 2014

Fingerprint

Gyrodactylus salaris
disease reservoirs
Salmo trutta
Thymallus
Salmo salar
parasites
infection
glaciation
Salmonidae
fish
hatcheries
salmon
Norway
Rosa
rivers

Keywords

  • Atlantic salmon
  • Brown trout
  • Grayling
  • Monogenea
  • Parasite
  • Pathogen
  • Salmo salar
  • Salmo trutta
  • Susceptibility
  • Thymallus thymallus

Cite this

Paladini, G ; Hansen, H ; Williams, CF ; Taylor, NGH ; Rubio-Mejia, OL ; Denholm, SJ ; Hytterod, S ; Bron, JE ; Shinn, AP. / Reservoir hosts for Gyrodactylus salaris may play a more significant role in epidemics than previously thought. In: Parasites Vectors. 2014 ; Vol. 7, No. 1. pp. 7 - 5.
@article{23c2b7ee617b471cba72e3e032f5292d,
title = "Reservoir hosts for Gyrodactylus salaris may play a more significant role in epidemics than previously thought",
abstract = "Background: Gyrodactylus salaris Malmberg, 1957 has had a devastating impact on wild Norwegian stocks of Atlantic salmon Salmo salar L., and it is the only Office International des Epizooties (OIE) listed parasitic pathogen of fish. The UK is presently recognised as G. salaris-free, and management plans for its containment and control are currently based on Scandinavian studies. The current study investigates the susceptibility of British salmonids to G. salaris, and determines whether, given the host isolation since the last glaciation and potential genetic differences, the populations under test would exhibit different levels of susceptibility, as illustrated by the parasite infection trajectory over time, from their Scandinavian counterparts. Methods: Populations of S. salar, brown trout Salmo trutta L., and grayling Thymallus thymallus (L.), raised from wild stock in UK government hatcheries, were flown to Norway and experimentally challenged with a known pathogenic strain of G. salaris. Each fish was lightly anaesthetised and marked with a unique tattoo for individual parasite counting. A single Norwegian population of S. salar from the River L{\ae}rdalselva was used as a control. Parasite numbers were assessed every seven days until day 48 and then every 14 days. Results: Gyrodactylus salaris regularly leads to high mortalities on infected juveniles S. salar. The number of G. salaris on British S. salar rose exponentially until the experiment was terminated at 33 days due to fish welfare concerns. The numbers of parasites on S. trutta and T. thymallus increased sharply, reaching a peak of infection on days 12 and 19 post-infection respectively, before declining to a constant low level of infection until the termination of the experiment at 110 days. Conclusions: The ability of S. trutta and T. thymallus to carry an infection for long periods increases the window of exposure for these two hosts and the potential transfer of G. salaris to other susceptible hosts. This study demonstrates that G. salaris can persist on S. trutta for longer periods than previously thought, and that the role that S. trutta could play in disseminating G. salaris needs to be considered carefully and factored into management plans and epidemics across Europe.",
keywords = "Atlantic salmon, Brown trout, Grayling, Monogenea, Parasite, Pathogen, Salmo salar, Salmo trutta, Susceptibility, Thymallus thymallus",
author = "G Paladini and H Hansen and CF Williams and NGH Taylor and OL Rubio-Mejia and SJ Denholm and S Hytterod and JE Bron and AP Shinn",
year = "2014",
month = "12",
day = "20",
doi = "10.1186/s13071-014-0576-5",
language = "English",
volume = "7",
pages = "7 -- 5",
journal = "Parasites Vectors",
number = "1",

}

Paladini, G, Hansen, H, Williams, CF, Taylor, NGH, Rubio-Mejia, OL, Denholm, SJ, Hytterod, S, Bron, JE & Shinn, AP 2014, 'Reservoir hosts for Gyrodactylus salaris may play a more significant role in epidemics than previously thought', Parasites Vectors, vol. 7, no. 1, pp. 7 - 5. https://doi.org/10.1186/s13071-014-0576-5

Reservoir hosts for Gyrodactylus salaris may play a more significant role in epidemics than previously thought. / Paladini, G; Hansen, H; Williams, CF; Taylor, NGH; Rubio-Mejia, OL; Denholm, SJ; Hytterod, S; Bron, JE; Shinn, AP.

In: Parasites Vectors, Vol. 7, No. 1, 20.12.2014, p. 7 - 5.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Reservoir hosts for Gyrodactylus salaris may play a more significant role in epidemics than previously thought

AU - Paladini, G

AU - Hansen, H

AU - Williams, CF

AU - Taylor, NGH

AU - Rubio-Mejia, OL

AU - Denholm, SJ

AU - Hytterod, S

AU - Bron, JE

AU - Shinn, AP

PY - 2014/12/20

Y1 - 2014/12/20

N2 - Background: Gyrodactylus salaris Malmberg, 1957 has had a devastating impact on wild Norwegian stocks of Atlantic salmon Salmo salar L., and it is the only Office International des Epizooties (OIE) listed parasitic pathogen of fish. The UK is presently recognised as G. salaris-free, and management plans for its containment and control are currently based on Scandinavian studies. The current study investigates the susceptibility of British salmonids to G. salaris, and determines whether, given the host isolation since the last glaciation and potential genetic differences, the populations under test would exhibit different levels of susceptibility, as illustrated by the parasite infection trajectory over time, from their Scandinavian counterparts. Methods: Populations of S. salar, brown trout Salmo trutta L., and grayling Thymallus thymallus (L.), raised from wild stock in UK government hatcheries, were flown to Norway and experimentally challenged with a known pathogenic strain of G. salaris. Each fish was lightly anaesthetised and marked with a unique tattoo for individual parasite counting. A single Norwegian population of S. salar from the River Lærdalselva was used as a control. Parasite numbers were assessed every seven days until day 48 and then every 14 days. Results: Gyrodactylus salaris regularly leads to high mortalities on infected juveniles S. salar. The number of G. salaris on British S. salar rose exponentially until the experiment was terminated at 33 days due to fish welfare concerns. The numbers of parasites on S. trutta and T. thymallus increased sharply, reaching a peak of infection on days 12 and 19 post-infection respectively, before declining to a constant low level of infection until the termination of the experiment at 110 days. Conclusions: The ability of S. trutta and T. thymallus to carry an infection for long periods increases the window of exposure for these two hosts and the potential transfer of G. salaris to other susceptible hosts. This study demonstrates that G. salaris can persist on S. trutta for longer periods than previously thought, and that the role that S. trutta could play in disseminating G. salaris needs to be considered carefully and factored into management plans and epidemics across Europe.

AB - Background: Gyrodactylus salaris Malmberg, 1957 has had a devastating impact on wild Norwegian stocks of Atlantic salmon Salmo salar L., and it is the only Office International des Epizooties (OIE) listed parasitic pathogen of fish. The UK is presently recognised as G. salaris-free, and management plans for its containment and control are currently based on Scandinavian studies. The current study investigates the susceptibility of British salmonids to G. salaris, and determines whether, given the host isolation since the last glaciation and potential genetic differences, the populations under test would exhibit different levels of susceptibility, as illustrated by the parasite infection trajectory over time, from their Scandinavian counterparts. Methods: Populations of S. salar, brown trout Salmo trutta L., and grayling Thymallus thymallus (L.), raised from wild stock in UK government hatcheries, were flown to Norway and experimentally challenged with a known pathogenic strain of G. salaris. Each fish was lightly anaesthetised and marked with a unique tattoo for individual parasite counting. A single Norwegian population of S. salar from the River Lærdalselva was used as a control. Parasite numbers were assessed every seven days until day 48 and then every 14 days. Results: Gyrodactylus salaris regularly leads to high mortalities on infected juveniles S. salar. The number of G. salaris on British S. salar rose exponentially until the experiment was terminated at 33 days due to fish welfare concerns. The numbers of parasites on S. trutta and T. thymallus increased sharply, reaching a peak of infection on days 12 and 19 post-infection respectively, before declining to a constant low level of infection until the termination of the experiment at 110 days. Conclusions: The ability of S. trutta and T. thymallus to carry an infection for long periods increases the window of exposure for these two hosts and the potential transfer of G. salaris to other susceptible hosts. This study demonstrates that G. salaris can persist on S. trutta for longer periods than previously thought, and that the role that S. trutta could play in disseminating G. salaris needs to be considered carefully and factored into management plans and epidemics across Europe.

KW - Atlantic salmon

KW - Brown trout

KW - Grayling

KW - Monogenea

KW - Parasite

KW - Pathogen

KW - Salmo salar

KW - Salmo trutta

KW - Susceptibility

KW - Thymallus thymallus

U2 - 10.1186/s13071-014-0576-5

DO - 10.1186/s13071-014-0576-5

M3 - Article

VL - 7

SP - 7

EP - 5

JO - Parasites Vectors

JF - Parasites Vectors

IS - 1

ER -