Author: marina02

Complete Genome Analysis of a Novel Lymphocystivirus Originating from Orbicular Batfish (Platax orbicularis)

Lymphocystiviruses are large dsDNA viruses belonging to the genus Lymphocystivirus within the family Iridoviridae. Lymphocystis disease virus (LCDV) is the causative agent of lymphocystis disease (LCD), a chronic but typically non-lethal condition, which reported to affect a wide range of teleost fish species in both freshwater and saltwater worldwide. LCDVs induce the formation of distinctive hypertrophied cells, known as lymphocystis cells, primarily on the body surface and fins. Virions can be found in high concentrations inside these cells. The disease is characterized by macroscopic whitish nodules that greatly affect the marketability and health of infected fish.

A diseased orbicular batfish (Platax orbicularis) showing typical signs of lymphocystis disease, was investigated by PCRs. In the first round, 6 core genes were amplified and sequenced by consensus primers. The sequence analysis suggested that the orbicular batfish LCDV (LCDV-OB) is probably a novel virus species. Hence, complete genome sequencing was carried out with Illumina platform. Short gaps between the contigs, and some further sequence ambiguities were resolved using PCRs and Sanger sequencing. Subsequently, bioinformatic analysis of the complete genome was performed.

The genome of LCDV-OB was found to be 296,946 bp in size. The G+C content of the whole genome was 36.6%. Comparison of the genome sequence of LCDV to those of the known LCDVs showed that the genome size of LCDV-OB is the longest, and its G+C content is the highest. The genome organization of the LCDV-OB shows similarity to that of the LCDV-3, but some gene rearrangements are also observable. The LCDV-OB genome was predicted to contain 188 putative genes. The majority of them (109) showed clear homology to the genes of other LCDVs. The 26 core genes, which are conserved in all sequenced iridoviruses, were also identified in the genome. Bioinformatic analysis revealed lower than 95% similarity between the majority of the LCDV-OB core genes (20) and the previously described LCDV core genes.

According to the current species demarcation criteria for the members of the family Iridoviridae, viruses are classified within the same species if they share ≥95% amino acid sequence identity in the predicted products of their core genes. Furthermore, members of the same species have to have a similar genome size and G+C content, and they should show phylogenetic relatedness and a co-linear gene arrangement. The analysis of the complete genome sequence of LCDV-OB confirmed that LCDV-OB is a member of a novel species in the genus Lymphocystivirus.

1. Mitró, Gergő, HUN-REN Veterinary Medical Research Institute, Presenter
2. Hoitsy, Márton, University of Veterinary Medicine Budapest, Author
3. Doszpoly, Andor, HUN-REN Veterinary Medical Research Institute, Author

Invasive Asian carp as potential reservoirs for emerging viral pathogens in the Great Lakes watershed

Introduction

Invasive Asian carp species, including Silver (Hypophthalmichthys molitrix), Bighead (H. nobilis), Grass (Ctenopharyngodon idella), and Black Carp (Mylopharyngodon piceus) after successfully establishing populations in the Mississippi River basin are now advancing towards the Great Lakes watershed through the Illinois River. Beyond their well-documented ecological impacts, we hypothesize that these species may also serve as reservoirs for aquatic pathogens, posing a severe ecological threat to native fish populations. Cyprinid herpesvirus 3 (CyHV-3, aka Koi herpesvirus, KHV) and Carp edema virus (CEV) are globally causing seasonal mortality outbreaks in wild and farmed carp, although their impact on North American native and invasive fishes remains unknown.

Methodology

Taking advantage of the invasive Asian carp mass removal campaigns operated by the DNR in the Illinois River, we sampled fishes during the late spring and summer of 2024 and 2025. Specimens were collected for molecular, virological, and histological examinations. CyHV-3 and CEV were detected and quantified by qPCR.

Results

Both viruses were detected in large asymptomatic adults of invasive Silver and Bighead Carp. Interestingly both viruses were also detected in native non-carp species, such as Freshwater Drum (Aplodinotus grunniens), Smallmouth (Ictiobus bubalus) and Bigmouth Buffalo (I. cyprinellus). Sequence analysis revealed that CEV strains belong to the Genogroup II, while the CyHV-3 strain to the European genotype.

Conclusions

This study further confirms the detection of CyHV-3 and CEV in invasive species getting closer to the Great Lakes and provides new evidence on the detection of these viruses from native Freshwater Drum and Ictiobus sp., with preliminary evidence of naturally occurring co-infections. The presence of these fish viruses in large asymptomatic fishes, combined with low viral burdens, failed attempts to isolate CyHV-3, and amplify CyHV-3 mRNA, suggests the occurrence of latent or inactive viral stages. The spread of CyHV-3 and CEV through highly invasive Asian carp species could enhance viral exposure and disease transmission to native fish populations.

1. Lamichhane, Santosh, Fish Pathobiology and Immunology Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA, Presenter
2. Widloe, Justin, Illinois Department of Natural Resources, Yorkville, IL, USA, Author
3. Fusianto, Cahya K., Fish Pathobiology and Immunology Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA, Author
4. Zupičić, Ivana Giovanna, Croatian Veterinary Institute, Zagreb, Croatia, Author
5. Gorgoglione, Bartolomeo, Fish Pathobiology and Immunology Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA, Author

Synthetic peptides prevent red grouper nervous necrosis virus absorption improving survival after infection in European sea bass

Introduction
Betanodavirus rank among the most challenging fish viral threats to the global aquaculture industry. They are uncoated, positive-sensed, single-stranded RNA viruses which possess a bipartite genome, with one segment encoding the capsid protein and the other coding for the RNA-dependent RNA polymerase. Four parental genotypes are distributed across four continents, while two reassortant genotypes have expanded the known host tropism. Despite extensive efforts to develop preventive and therapeutic strategies from various perspectives, success has remained limited. Currently, only two commercial vaccines provide partial protection against a single genotype, highlighting the urgent need for further effective control measures.
Methodology
In this study, we designed and synthesized peptides from the red grouper betanodavirus (RGNNV) capsid protein. Their antiviral activity was evaluated in vitro against RGNNV, SJNNV and their reassortants. In addition, their therapeutic potential was tested in experimentally infected European seabass (Dicentrarchus labrax) juveniles.
Results
Most of the designed peptides exhibited nearly 100% in vitro activity against all the NNV genotypes when applied together, being highest against RGNNV and lowest for SJNNV/RGNNV. Interestingly, P4 also reduces the intracellular and extracellular RGNNV load. In vivo, they improved survival rates and mitigated disease symptoms by reducing viral loads in the brain, the primary target tissue of the virus.
Conclusions
These peptides are suggested to disrupt viral absorption though partial reduction of viral replication appears to be more related to immune responses in the host. Current preventive and therapeutic strategies against betanodavirus have proven insufficient, allowing its uncontrolled spread. Designing peptides capable of disrupting key stages of the viral life cycle represents a novel approach that could advance its viral treatment.
Funding

This research was carried out thanks to grants PID2022-139492NB-I00 funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU to A.C., PREP2022-000442 funded by MICIU/AEI/10.13039/501100011033 and by ESF+ to A.H-S., and the grant IJC2020-042733-I from MICIU/AEI/10.13039/501100011033 and by the European Union NextGenerationEU/PRTR, to Y.V.

1. CUESTA, ALBERTO, UNIVERSIDAD MURCIA, Presenter
2. FERNÁNDEZ-HERNÁNDEZ, FRANCISCO J., UNIVERSIDAD MURCIA, Author
3. HERNÁNDEZ-SENDRA, ANA C., UNIVERSIDAD MURCIA, Author
4. CÁRDENAS, CONSTANZA, PONTIFICIA UNIVERSIDAD CATÓLICA DE VALPARAÍSO, Author
5. GUZMÁN, FANNY, PONTIFICIA UNIVERSIDAD CATÓLICA DE VALPARAÍSO, Author
6. VALERO, YULEMA, UNIVERSIDAD MURCIA, Author

Influence of temperature on the course of SVCV infection in carp

Environmental temperature is a defining force in the ecology of freshwater fish and the pathogens that exploit them. Nowhere is this more evident than in spring viremia of carp virus (SVCV), an enveloped rhabdovirus whose outbreaks typically coincide with the cold edge of the growing season. To dissect how temperature shapes the tug-of-war between virus and host, we exposed specific-pathogen-free common carp (Cyprinus carpio) to SVCV by standardized bath challenge and held parallel cohorts at 12 °C or 20 °C for four weeks. The lower temperature mirrors late-winter pond conditions when adaptive immunity is naturally depressed; the higher temperature reflects summer, when cellular and humoral responses are generally robust.

At seven-day intervals, we sampled the kidney, spleen, and gill to quantify viral burden (RT-qPCR assay) and to chart host immunity. Flow cytometry was employed to elucidate the B and T lymphocyte kinetics, while high-throughput QPCR was applied to capture transcriptional programs underpinning innate signaling, interferon effector cascades, and immunoglobulin gene expression. Virus-specific IgM levels were tracked by ELISA, and functional activity was verified in neutralization assays against a homologous SVCV strain.

Across the 28-day window, fish maintained at 12 °C harbored markedly higher and more persistent viral loads, consistent with clinical observations of cold-season outbreaks. In parallel, these fish displayed distinct lymphocyte trafficking and transcriptomic signatures skewed toward pattern-recognition and pro-inflammatory mediators rather than adaptive effectors. By contrast, carp held at 20 °C curtailed SVCV replication sooner and developed measurable adaptive responses. Mortality patterns mirrored these molecular trends, emphasizing the protective edge conferred by a fully engaged adaptive response.

Together, the study delineates a clear temperature-dependent “window of vulnerability” during which SVCV outruns host defenses. Beyond its relevance for spring viremia control, the work illustrates how seasonal physiology can rewrite the rules of host–virus interaction in ectotherms. Mapping these temperature-immunity intersections provides an evidence base for timing prophylactic vaccination, adjusting husbandry practices, and forecasting disease risk in temperate carp aquaculture as climate variability reshapes thermal regimes.

1. PIAČKOVÁ, VERONIKA, UNIVERSITY OF SOUTH BOHEMIA IN ČESKÉ BUDĚJOVICE, Czech Republic, Presenter
2. Sebastian, Anju, UNIVERSITY OF SOUTH BOHEMIA IN ČESKÉ BUDĚJOVICE, Czech Republic, Author
3. Adamek, Mikolaj, University of Veterinary Medicine Hannover, Hannover, Germany, Author
4. Mičůchová, Alžběta, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Czech Republic, Author
5. Frébort, Ivo, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Czech Republic, Author
6. Kyslík, Jiří, Biology Centre CAS, Institute of Parasitology, České Budějovice, Czech Republic, Author
7. Korytář, Tomáš, Biology Centre CAS, Institute of Parasitology, České Budějovice, Czech Republic, Author

Development of a Real-Time Recombinant Polymerase Amplification (RPA) assay for the sensitive, rapid detection of Spring Viremia of Carp Virus (SVCV)

Introduction: Infection with the rhabdovirus Spring Viremia of Carp Virus (SVCV) can cause serious disease in cyprinids, posing a significant threat to aquaculture. Currently, the World Organisation for Animal Health (WOAH) recommends tissue culture and conventional PCR with confirmatory sequencing for SVCV diagnosis, alongside other methodologies such as antibody-based assays which may cross-react with close relatives. These techniques are labour-intensive and time-consuming. Existing real-time PCR tests have not been adequately evaluated to detect all SVCV genogroups. To address this challenge, we are developing and validating isothermal recombinase polymerase amplification (RPA) tests for rapid detection of European and Asian strains of SVCV.

Methodology: We sequenced the genome of approximately 100 SVCV isolates from various geographical locations and designed RPA primers targeting a conserved region of the viral RNA-dependent RNA polymerase gene (L). The specificity and sensitivity of the primers were evaluated using the TwistAmp basic RPA kit in a 20-minute run at 40°C with both European and Asian SVCV isolates, cyprinid cell lines (Epithelioma Papulosum Cyprini and common carp brain) as negative controls, and closely related rhabdoviruses: pike fry rhabdovirus (PFRV) and tench rhabdovirus (TeRV) to evaluate cross-reactions. The most promising tests were subsequently evaluated in a real-time RPA assay using the TwistAmp exo kit and an RPA-probe designed according to the TwistDx assay design recommendations.

Results: We successfully designed RPA primer sets that can detect both European and Asian SVCV genogroups within 20 minutes; however, cross reaction with the rhabdovirus PFRV was observed when using the TwistAmp basic kit. The introduction of a highly specific RPA-probe in a real-time RPA test eliminated the cross reaction with the closely related rhabdovirus, enabling the detection of SVCV in just 5 minutes for samples containing 105 copies of the targeted viral gene and with a detection limit of 100 copies after a 15-minute run.

Conclusion: These fast and user-friendly RPA assays can detect all known SVCV genogroups allowing for the development of point-of-care tests and faster responses at border inspection posts.

1. Jones, Charlie, Cefas, Presenter
2. Hong, Liu, Shenzhen Customs, Animal & Plant Inspection and Quarantine Technology Center, Author
3. SUN, JIE, Cefas, Author
4. Savage, Jacqueline, Cefas, Author
5. Cano-Cejas, Irene, Cefas, Author

Molecular Cloning and Characterization of C-X-C motif chemokine-11 (CXCL11) from seven-band grouper (Hyporthodus septemfasciatus)

Nervous necrosis virus (NNV) is a major viral pathogen in marine aquaculture, causing high mortality in economically important species such as the sevenband grouper (Hyporthodus septemfasciatus). Outbreaks of viral nervous necrosis (VNN) significantly affect larval stages, leading to substantial economic losses. Chemokines play a crucial role in regulating immune responses, with CXCL11 known to bind CXCR3 receptors, promote Th1-skewed immunity and exhibit antimicrobial activity similar to defensins. CXCL11 has also been implicated in recruiting activated T cells and enhances antiviral environments at infection sites. However, in teleosts, the immunological roles of CXCL11 remain largely unexplored. Therefore, further investigation is required to elucidate the function of CXCL11 in teleost immunity, particularly in the context of viral infections such as NNV.

To investigate the role of CXCL11 in groupers, a prokaryotic expression system was established. The full-length cDNA of CXCL11 is 762 bp, including a 208 bp 5’-UTR, a 342 bp open reading frame (ORF) encoding a 113 amino acid protein, and a 212 bp 3’-UTR. The ORF was amplified by PCR using gene-specific primers designed from transcriptome data, and the product was confirmed via agarose gel electrophoresis before subcloning into the cold-shock expression vector pColdI for recombinant protein expression. SMART domain analysis revealed the presence of an SCY domain spanning residues 26–87, which is commonly associated with chemokine-like cytokines and innate immune functions, including antimicrobial and immunomodulatory activities. A highly conserved region was identified within the domain of CXCL11 across multiple species, including fish and mammals, indicating that this sequence may play a critical role in its immunological function. Phylogenetic analysis of CXCL11 from Hyporthodus septemfasciatus revealed a close relationship with other Serranidae species, supported by high sequence conservation. Despite forming distinct clades, vertebrates including Danio rerio, Bos taurus, and Mus musculus shared conserved domain features, suggesting the functional importance of CXCL11 across species. Phobius-based signal peptide prediction, visualized with Protter, revealed an N-terminal signal sequence (residues 1–20), suggesting that CXCL11 may be secreted.

Future research will involve large-scale production and purification of recombinant CXCL11, followed by cell-based functional assays to investigate its antiviral and immunomodulatory roles in the grouper immune system. This work is expected to advance our understanding of the molecular basis of antiviral immunity in groupers and contribute to the development of immune-based strategies for disease control in aquaculture.

1. LIM, CHAE-WON, PUKYONG NATIONAL UNIVERSITY, Presenter
2. JUNG, JAE-EUN, PUKYONG NATIONAL UNIVERSITY, Author
3. SEO, JEONG-MIN, PUKYONG NATIONAL UNIVERSITY, Author
4. PARK, JI-HWAN, PUKYONG NATIONAL UNIVERSITY, Author
5. JEON, SO-YEON, PUKYONG NATIONAL UNIVERSITY, Author
6. LEE, SONG-YI, PUKYONG NATIONAL UNIVERSITY, Author
7. OH, MYUNG-JOO, CHONNAM NATIONAL UNIVERSITY, Author
8. KIM, JONG-OH, PUKYONG NATIONAL UNIVERSITY, Author

Tilapia Lake virus induces mitochondrial disruption and apoptotic cell death in E-11 cells

Tilapia Lake Virus (TiLV) is a significant pathogen in tilapia aquaculture, causing extensive mortality and economic losses. This study integrates proteomic, phosphoproteomic, and ultrastructural analyses to elucidate TiLV-induced cell death mechanisms in E-11 cells. Transmission electron microscopy revealed the presence of TiLV particles in the cytoplasm within 1 hour post-infection, with progressive mitochondrial swelling and ultrastructural damage over time. Functional assays demonstrated mitochondrial membrane depolarization, ATP depletion, and increased cytotoxicity, suggesting mitochondrial dysfunction as a primary driver of cell death. Proteomic and phosphoproteomic profiling further identified key alterations in apoptotic and inflammatory signaling pathways. Early infection led to suppression of Janus kinase (JAK)-signal transducer and activator of transcription (STAT) and Fas-associated death domain (FADD)-tumor necrosis factor receptor-associated factor (TRAF) pathways, while later stages activated nucleotide oligomerization domain (NOD)-like receptor signaling, further promoting apoptosis. These findings highlight TiLV’s ability to hijack host cellular pathways to enhance viral replication while triggering mitochondrial damage and programmed cell death. Understanding these mechanisms provides crucial insights into TiLV pathogenesis and may contribute to the development of targeted antiviral strategies to mitigate its impact on global tilapia production.

1. LERTWANAKARN, TUCHAKORN, Department of Physiology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand, Presenter
2. SURACHETPONG, WIN, Department of Veterinary Microbiology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand, Author

Susceptibility of European sea bass and gilthead seabream brain cell lines to NNV infection

Introduction
The nervous necrosis virus (NNV) is responsible for viral encephalopathy and retinopathy (VER), mainly targeting the brain and retina, and considered one of the most significant diseases affecting European aquaculture. In the Mediterranean aquaculture sector, the European seabass (Dicentrarchus labrax) and the gilthead seabream (Sparus aurata) are the most widely cultivated species. Sea bass is highly susceptible to NNV infection, showing mortality rates up to 100% in larvae and juveniles, whereas seabream is generally considered more resistant, although natural outbreaks with typical VER symptomatology have been reported in seabream hatcheries.
Methodology
In this study, we evaluated the differential susceptibility of the DLB-1 (D. labrax brain cell line) and SaB-1 (S. aurata brain cell line) cell lines to infection by different NNV genotypes at 6, 24, 48, and 72 h post-infection. Cell-NNV interactions were quantified through real-time polymerase chain reaction (qPCR) by analyzing the expression of viral genes, specifically the capsid and the RNA-dependent RNA polymerase (RdRP), along with a selected panel of inducible genes. Additionally, the analysis was complemented by Western blotting to evaluate the presence of viral proteins.
Results
Overall, the results obtained show great differences between the cell lines and the genotypes, usually with a higher expression of viral genes observed for the RGNNV genotype at 48 and 72 h post-infection and variable regulation of the host immune genes. These findings suggest that viral replication progressively increases over time, and that the RGNNV genotype exhibits a stronger replication kinetics compared to the other genotypes.
Conclusions
Our findings provide a deeper understanding of NNV infection in vitro assays, offering relevant data on viral replication dynamics over time and highlighting differences in host-virus interactions. These models are expected to be used in future studies for the development of antiviral strategies.
Funding: This research was carried out thanks to grant PID2022-139492NB-I00, funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU to A.C., and PREP2022-000442 funded by MICIU/AEI/10.13039/501100011033 and by ESF+ to A.C.H-S.

1. CUESTA, ALBERTO, UNIVERSIDAD MURCIA, Presenter
2. HERNÁNDEZ-SENDRA, ANA C., UNIVERSIDAD MURCIA, Author

Regulatory Mechanism of Protein Kinase R in Giant Grouper and Interaction with Nervous Necrosis Virus (NNV)

Protein kinase R (PKR) is a key antiviral protein that is activated by viral double-stranded RNA (dsRNA) and mediates host defense by phosphorylating eIF2α, leading to inhibition of protein translation and viral replication. Our previous research demonstrated that PKR expression in giant grouper (Epinephelus lanceolatus) is positively correlated with infection by nervous necrosis virus (NNV). However, the upstream regulation and downstream effects of PKR in teleosts remain unclear. To investigate the regulatory mechanisms of giant grouper PKR (ggPKR), we first analyzed the promoter region of theggPKR gene to identify transcription factor binding sites. We then conducted gain-of-function and loss-of-function experiments using the GF-1 grouper fin cell line to evaluate ggPKR-associated signaling pathways. In addition, GF-1 cells were treated with poly(I:C), heat shock, and recombinant IFN to induce PKR expression and mimic environmental stress and viral stimuli. Expression levels of PKR and downstream immune-related genes were quantified using qPCR and Western blotting. Promoter analysis revealed several putative binding sites for transcription factors related to immune and stress responses. Poly(I:C), heat shock, and cytokine treatments significantly upregulated ggPKR expression, confirming its inducibility under viral and stress-related conditions. Gain-of-function assays showed that overexpression of ggPKR activated downstream genes involved in antiviral response and apoptosis, while knockdown of ggPKR reduced these effects. Furthermore, ggPKR modulation altered the susceptibility of GF-1 cells to NNV infection, supporting its functional role in viral defense. This study provides novel insights into the regulatory network of PKR in giant grouper and demonstrates its involvement in immune signaling and cellular stress responses. Our findings confirm that ggPKR is inducible by viral dsRNA and environmental stress, also plays a critical role in host defense against NNV. This is the first report to characterize PKR regulation and function in a teleost species, contributing to the understanding of antiviral mechanisms in fish and supporting the development of disease-resistant aquaculture strains.

1. TZONG-YUEH, CHEN, NATIONAL CHENG KUNG UNIVERSITY, Presenter
2. SIH-SHIEN, LEE, National Cheng Kung University, Author

PRV3 in Italy: results from a local surveillance study

Introduction

PRV3, a member of the Orthoreovirus genus, has been associated with heart inflammation and muscle disease in rainbow trout (O. mykiss) in certain countries. Orthoreoviruses are widespread within their respective niches, and their detection alone does not necessarily imply disease causality. PRV3 has been reported in several European countries, but in Italy, it was only detected once in 2017 with any associated disease outbreak. This study aimed to investigate the presence of the PRV3 in the area with the highest salmonids production in Italy.

Methodology

Samples were collected as part of routine surveillance activities targeting both farmed and wild fish populations, within a monitoring program aimed at maintain freedom from Viral Hemorrhagic Septicemia (VHS) and Infectious Hematopoietic Necrosis (IHN) in officially recognized disease-free zones. In addition, samples collected during mortality outbreaks in the same period were also included. The sampling period spanned approximately one year (September 2023 to June 2024) and covered three regions in northern Italy: Veneto, Friuli Venezia Giulia, and Trentino-Alto Adige. Specimens consisted of pooled organs (spleen, kidney, and heart) or ovarian fluid from 10 fish, homogenized in Minimum Essential Medium (MEM) for cell culture. Generic PRV real-time RT-PCR (pan-PRV rRT-PCR) was employed as the screening method, and positive samples were further characterized using PRV3-specific end-point RT-PCR followed by Sanger sequencing. The geographic distribution of PRV3, was visualised using ArcGIS ArcGIS Version 10.8.2; Esri Inc. – 2022) and QGIS 3.22.

Results

Of the 270 specimens tested, 37.4 % of yielded positive results by pan-PRV rRT-PCR, corresponding to 43.6 % positive farms in the study area (out of 78 tested). The species most frequently detected as positive was S. trutta, followed by O. mykiss and S. marmoratus. No clinical signs or history of mortality were reported from the positive batches of fish by the farmers. Interestingly, healthy wild fish also tested positive, while none of the samples from mortality events yielded positive results. Phylogenetic analysis of the positive samples confirmed that the Italian strains clustered within group 3b, consistent with previously detected strains in Italy.

Conclusions

This study represents the first attempt to assess the presence and prevalence of the PRV3 in Italy. The results suggest that PRV3 is widespread in both farmed and wilds salmonid populations in the investigated area. The large number of positive fish and farms, without any associated disease, suggest that PRV3 does not cause health issues under the current farming conditions.

1. DRZEWNIOKOVA, PETRA, ISTITUTO ZOOPROFILATTICO SPERIMENTALE DELLE VENEZIE, Author
2. LUCON XICCATO, ROMY, ISTITUTO ZOOPROFILATTICO SPERIMENTALE DELLE VENEZIE, Author
3. CASAROTTO, CLAUDIA, ISTITUTO ZOOPROFILATTICO SPERIMENTALE DELLE VENEZIE, Author
4. FERRE’, NICOLA, ISTITUTO ZOOPROFILATTICO SPERIMENTALE DELLE VENEZIE, Author
5. MAZZUCATO, MATTEO, ISTITUTO ZOOPROFILATTICO SPERIMENTALE DELLE VENEZIE, Author
6. TOSON, MARICA, ISTITUTO ZOOPROFILATTICO SPERIMENTALE DELLE VENEZIE, Author
7. TOFFAN, ANNA, ISTITUTO ZOOPROFILATTICO SPERIMENTALE DELLE VENEZIE, Presenter