16th EAFP INTERNATIONAL CONFERENCE ON DISEASES OF FISH AND SHELLFISH Tampere, September 2-6, 2013 BOOK OF ABSTRACTS DISCLAIMER: The organizer takes no responsibility for any of the content stated in the abstracts. The abstract book contains abstracts as provided by their authors. No editing has been done except for spelling corrections. Published for: European Association of Fish Pathologists, 2013 Printed in Nykypaino, Helsinki Copyright © European Association of Fish Pathologists All rights reserved. No parts of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, xerography, or any information storage and removal system, without permission from the compiler. Picture front cover: Reflections © Ruud Dirks BOOK OF ABSTRACTS Contents KEYNOTES Conference Keynote 7 Keynotes 2-4 8 ORAL PRESENTATIONS 11 Viruses and viral diseases I 12 Nutrition and fish health 17 Bivalve and crustacean diseases 24 Fish and shellfish immunology I 31 Diseases of sturgeon, wild and ornamental fish 36 Viruses and viral diseases II 42 Myxozoan I 48 Non-transmissible problems 55 Aquatic animal epidemiology I 60 Myxozoan II 65 Host-parasite interactions I 72 Vaccines and vaccinology I 79 Bacterial diseases I 86 Fish and shellfish immunology II 92 Aquatic animal epidemiology II 99 Parasitic diseases 105 Host-parasite interactions II 111 Vaccines and vaccinology II 118 Flavobacteria 125 Viruses and viral diseases III 132 Bacterial diseases II 139 Diagnostics 145 POSTER PRESENTATIONS 154 Viruses and viral diseases 155 Nutrition and fish health 207 Bivalve and crustacean diseases 223 Fish and shellfish immunology 239 Diseases of sturgeon, wild and ornamental fish 275 Myxozoa 289 Non-transmissible problems 304 Aquatic animal epidemiology 322 Host-parasite interactions 345 Vaccines and vaccinology 362 Bacterial diseases 367 Parasitic diseases 388 Flavobacteria 409 Diagnostics 416 Prophylaxis and treatment 427 Problems in recirculation 428 WORKSHOPS 431 ADDITIONAL ABSTRACTS 437 AUTHOR’S CONTACT 440 CKN Conference keynote HISTOPATHOLOGY: A KEY INTEGRATIVE TOOL FOR AQUATIC ANIMAL DISEASES David Bruno Marine Scotland Science, Aberdeen, Scotland Gross pathology can be frustratingly similar, and difficult for inexperienced personal to distinguish between different pathological conditions, notably where overlapping infections may be present, challenging the histopathologist to differentiate between ‘dying of’ from ‘dying with’ a given agent. The examination of stained tissue sections remains a gold standard for pathological investigations in human and veterinary medicine and no less important in wild fisheries and aquaculture. The significant technological advances particularly the advent of molecular biology has contributed to our understanding of specific proteins, viruses and enzymes in tissues. However, to make ‘biological sense’ of these data histopathology is essential and integral to all aspects of fish health whether it be for emerging diseases, diagnostic investigations or for pure research. In all cases judgment based on case-history observations, research findings, familiarity with the literature, experience, diagnostic test results help reach an accurate interpretation or result. Curiosity and an open mind combined with thorough knowledge and experience will remain an important attitude for the fish pathologist. 7 KN-2 FISH VIROLOGY: MECHANISMS AND EVOLUTION OF VIRULENCE N.J. Olesen National Veterinary Institute, Technical University of Denmark, Frederiksberg, Denmark Unlikely in animal husbandry viral infections in aquaculture often tend to develop towards increased severity. Understanding virus evolution towards increased pathogenicity in the aquaculture environment is a requirement for being able to taking appropriate actions to prevent it. Some of the recent studies concerning virulence mechanism will be presented and discussed with focus on VHSV, ISAV and IPNV. For these viruses only very few nucleotide mutations, inserts or deletions suffice to completely change the pathogenicity pattern in various species. Some changes involve the adhesion and entrance into to the fish and cells while others influence the virus replication and release. A review on some of the fascinating in vitro and in vivo studies recently conducted will be given. Priority should be given to studies that a. Demonstrate pathogen mutagenesis, e.g by including historical field samples in experimental trials and genetic analyses b. Identify virulence markers and traits. c. Assess factors that trigger increases in pathogen virulence d. Assess risk of pathogen mutagenesis towards increased pathogenicity e. Assess risk of presence of low pathogenic strains for disease development in aquaculture f. Establish thresholds for pathogen discrimination g. Design management strategies for preventing virulence evolution When the understanding of virulence mechanisms have improved appropriate actions can include specific vaccination strategies, treatment strategies and operational procedures which take into consideration the risk of virulence evolution under aquaculture conditions. 8 KN-3 DEVELOPING VACCINES IN THE ERA OF GENOMICS D. Maione Biochemistry and Molecular Biology Novartis Vaccines & Diagnostics Vaccines have a significant impact on human and animal health. Vaccinology in the era of genomics is taking advantage of new technologies to tackle diseases for which vaccine development has so far been unsuccessful. The availability of complete genome sequences of a pathogen provides access to its entire antigenic repertoire. Genomics has induced a shift in vaccine development towards sequence-based 'Reverse Vaccinology' approaches, which use high-throughput in silico screening of the entire genome of a pathogen that enable rapid targeted identification of novel vaccine antigens. Furthermore, the increasing availability of genome sequences has led to the development and application of additional technologies to vaccine discovery, including comparative genomics, transcriptomics, proteomics, structural biology and immunomics. Vaccine candidates identified from a pathogen's genome or proteome can then be expressed as recombinant proteins and tested in appropriate in vitro or in vivo models to assess immunogenicity and protection. The process of reverse vaccinology has been applied to several human pathogens, including serogroup B Neisseria meningitidis, Streptococcus agalactiae, Streptococcus pyogenes, Streptococcus pneumoniae and pathogenic Escherichia coli, and has provided scores of new candidate antigens for preclinical and clinical investigation. These powerful technologies are now expected to accelerate the identification of candidates also for the development of vaccines against animal pathogens. 9 KN-4 MAKING THE CASE FOR DISEASE FREEDOM – WHAT CAN EPIDEMIOLOGY CONTRIBUTE? E.J. Peeler Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK A central tenet of EU aquatic animal health legislation and international standards is that susceptible species can only be traded live between areas of equal health status (or from a higher to lower status) for listed diseases. Thus demonstrating disease freedom is crucial to maintaining a high health status. Epidemiology provides the scientific underpinning to the design and analysis of surveillance to demonstrate freedom. Methods, implemented in free software (e.g. FreeCalc), to calculate sample sizes for structured surveys now take account of the minimum detectable prevalence and test characteristics, leading to improved design and interpretation of surveillance to demonstrate freedom. Scenario tree modelling (STM) goes further by allowing non-structured data sources to be used and for sampling to focus on high risk regions or farms, i.e. risk based surveillance. These methods enabled a move from input (e.g. 30 samples from every farm) to output based standards (e.g. demonstrate freedom with 95% confidence that the pathogen is not present above 2%). Recent decisions in Europe on disease freedom illustrate epidemiology’s wide role, over and above the technical challenges of surveillance. In the UK a decision not to attempt eradication of koi herpes virus was in part based on mathematical modelling of the spread of disease under different scenarios that quantified the likelihood of success, and time-scale, of an eradication programme. No EU Member State has made a case to demonstrate freedom from white spot syndrome virus, despite an absence of outbreaks. This is discussed alongside consideration of how import risk analysis (IRA) supports decisions about mitigation measures to maintain freedom. The EU ceased listing epizootic ulcerative necrosis as an exotic disease in part due to the likely costs of necessary trade restrictions (the decision was also informed by risk assessments of the likelihood and consequences of introduction). Epidemiology provides many of the solutions to the technical questions that arise when making the case for disease freedom. However, governments must balance the potentially competing interests of all stakeholders, including consumers. To this end socio-economic analysis, informed by epidemiological data, of the costs and benefits of disease freedom is also crucial. 10 ORAL PRESENTATIONS 11 O-001 VIRAL HEMORRHAGIC SEPTICEMIA VIRUS (VHSV) GENOTYPE IVB IS A POTENTIAL THREAT TO WILD FRESH WATER FISH IN JAPAN T. Ito*1 and N.J. Olesen2 1National Research Institute of Aquaculture, Fisheries Research Agency, Mie, Japan 2National