Event Abstract Back to Event “She’s got the ticket to ride, but she don’t care” (The Beatles, 1965) The epidemiology of Gyrodactylus salaris in the best wild salmon river in the Baltic Sea basin Perttu Koski1* and Jaakko Lumme2 1 Finnish Food Safety Authority Evira, Finland 2 University of Oulu, Department of Biology, Finland Tornionjoki river system is nowadays the most productive wild salmon river in the Baltic Sea water catchment area. We followed the subclinical Gyrodactylus salaris infection of salmon parr at four indicator areas during 2000-2012 (number of fish, nfish=2571). The uppermost tributary, River Lätäseno (460 km from the river mouth), had the highest mean apparent prevalence (47.4%) and the lowest part, R. Tornionjoki along the Finnish-Swedish border, the lowest (11.0%). The infection was more common in two summer old and older (mean 31.1%) than in the parr of the first summer (mean 10.1%). The associations of the watercourse sections and the age of the parr with the infection were clear in binary logistic regression. Adjusted odds ratio was 6.7 in R. Lätäseno, 2.4 in R. Könkämäeno and 1.9 in R. Muonionjoki in comparison with R. Tornionjoki. Possible water quality determinants (e.g. high aqueous aluminum concentrations) behind this upside-down pattern need further research. The genetic structure of the parasite population was studied by sequencing an anonymous nuclear DNA marker (ADNAM1, three main genotypes) and mitochondrial CO1 (three clades, six haplotypes). During the ten years 2000-2009, the parasite population was strongly and stably genetically differentiated among up- and downstream nurseries (nADNAM1 = 411, fixation index based on genotype/haplotype frequencies, FST = 0.579; nCO1 = 443, FST = 0.534). The nuclear and mitochondrial markers were in stable disequilibrium which was not relaxed in the contact zone or among the smolt where the parasite clones often met on individual fish. The host salmon population in Tornio River is known to show significant spatial differentiation (FST = 0.022). The stable spatial genetic structure of the parasite against the high physical mobility suggested a possibility of local co-adaptation of the host-parasite subpopulations. Acknowledgements Several other researches in addition to the authors of the references participated in the monitoring or molecular biology work of Gyrodactylus: Ville Vähä and Kari Pulkkinen, Natural Resources Institute Finland (LUKE), Petra Heikkinen and Liisa Alaoutinen, Evira and Laura Törmänen, University of Oulu. References Anttila, P., Romakkaniemi, A., Kuusela, J., Koski, P.. 2008. Epidemiology of Gyrodactylus salaris (Monogenea) in the River Tornionjoki, a Baltic wild salmon river. Journal of Fish Diseases 31, 373-382. Lumme, J., Anttila, P., Rintamäki, P., Koski, P., Romakkaniemi, A.. 2016. Genetic gradient of a host – parasite pair along a river persisted ten years against physical mobility: Baltic Salmo salar vs. Gyrodactylus salaris. Infection, Genetics and Evolution 45, 33-39. Keywords: Gyrodactylus salaris, Salmo salar, Epidemiology, Prevalence, Parasite dispersal, Baltic Sea, local adaptation Conference: AquaEpi I - 2016, Oslo, Norway, 20 Sep - 22 Sep, 2016. Presentation Type: Poster Topic: Aquatic Animal Epidemiology Citation: Koski P and Lumme J (2016). “She’s got the ticket to ride, but she don’t care” (The Beatles, 1965) The epidemiology of Gyrodactylus salaris in the best wild salmon river in the Baltic Sea basin. Front. Vet. Sci. Conference Abstract: AquaEpi I - 2016. doi: 10.3389/conf.FVETS.2016.02.00007 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Sep 2016; Published Online: 14 Sep 2016. * Correspondence: PhD. Perttu Koski, Finnish Food Safety Authority Evira, Oulu, Finland, perttu.koski@evira.fi Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Perttu Koski Jaakko Lumme Google Perttu Koski Jaakko Lumme Google Scholar Perttu Koski Jaakko Lumme PubMed Perttu Koski Jaakko Lumme Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.