Abstract

Global climate change is altering the abundance and spread of various parasites, which has important consequences not only for host-parasite interactions but also for the relationships between different host species. Here, we focus on the myxozoan endoparasite Tetracapsuloides bryosalmonae that causes temperature-dependent proliferative kidney disease (PKD) in salmonids. We characterized the temporal changes in the parasite load and the severity of PKD signs (renal hyperplasia, haematocrit) in two sympatric populations of wild brown trout (Salmo trutta) and Atlantic salmon (Salmo salar). We found that both the parasite load and disease signs vary considerably between individuals, species, rivers and sampling periods. We showed that Atlantic salmon was able to slow down the initial parasite proliferation rate and subsequently tolerate high parasite burden without obvious disease signs. In contrast, the initial parasite proliferation rate was much higher in brown trout, which was followed by the development of severe PKD signs. Thus, the speed of parasite proliferation, rather than the absolute number of the parasites in the host kidney, may play an important role in interspecific variation in PKD susceptibility. To conclude, this study illustrates the usefulness of temporal perspective for understanding host defence mechanisms and climate change-mediated impacts in the wild.

Keywords

fish disease; host-parasite relationships; myxozoa; parasite; salmonids; Tetracapsuloides bryosalmonae

Published in

Journal of Fish Diseases
2021, Volume: 44, number: 6, pages: 689-699

SLU Authors

• Vasemägi, Anti

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    
  • Estonian University of Life Sciences

UKÄ Subject classification

Zoology
Ecology


Publication identifier

DOI: https://doi.org/10.1111/jfd.13330

Permanent link to this page (URI)

https://res.slu.se/id/publ/109851