ParaFishControl will participate in the Workshop “Bottlenecks in Diagnostics of Mediterranean Fish Diseases” at EAFP 2019

MedAID, PerformFISH and ParaFishControl are organising the workshop “Bottlenecks in Diagnostics of Mediterranean Fish Diseases” at the 19th International Conference on Diseases of Fish and Shellfish that will take place in Porto from 9 to 12 September 2019. The workshop will be held on the 9th September 2019 from 16:00 to 19:00.

The farming of sea bass and sea bream is an important productive sector in the Mediterranean, significantly contributing to the local economy and job creation in rural and coastal areas. Sea bream and sea bass are by volume the third and fourth most farmed fish species in the European Union (EU). However, in recent years, there is a growing concern regarding the lack of growth and improvement in Mediterranean Marine Fish Farming which covers the majority of sea bass and sea bream production. For the last decade, overall production in the EU has remained stagnant and at present the industry is under a range of pressures, including technical, market-oriented, legislative and financial issues.

MedAID and PerformFISH H2020 projects aim to increase the overall competitiveness and sustainability of the Mediterranean marine fish-farming sector, throughout the whole value chain. An important aspect of both projects is managing transmissible diseases of farmed fish. On the other hand, ParaFishControl aims to improve understanding of fish-parasite interaction and to develop innovative solutions and tools for the prevention, control and mitigation of farmed fish parasitic diseases. These projects are actively cooperating in all possible aspects and the workshop will cover one of the mutual interests of these three EU H2020 projects: diagnostics.

The workshop is divided into three sessions. The first session is dedicated to present the different diagnostic techniques employed in Mediterranean fish farms for viral, bacterial and parasitic diseases. The second one will be dedicated to working group discussions on the main challenges for the implementation of standardised procedures and the bottlenecks in diagnostics of the mentioned pathogens. The discussion will be moderated by experts of MedAID, PerformFISH and ParaFishControl.The final plenary session will summarise the bottlenecks identified in the previous session and discuss the way forward to overcome them.

The summary of the discussions and conclusions is planned to be published at the EAFP Bulletin.

To attend this workshop, please register for EAFP here: https://skyros-congressos.pt/eafp2019/form.php.

 Click here to download the programme of the Workshop.

NEW ParaFishControl article "Acquired protective immune response in a fish-myxozoan model encompasses specific antibodies and inflammation resolution"

Acquired protective immune response in a fish-myxozoan model encompasses specific antibodies and inflammation resolution. Fish & Shellfish Immunology. doi: https://doi.org/10.1016/j.fsi.2019.04.300

The myxozoan parasite Enteromyxum leei causes chronic enteritis in gilthead sea bream (GSB, Sparus aurata) leading to intestinal dysfunction. Two trials were performed in which GSB that had survived a previous infection with E. leei (SUR), and naïve GSB (NAI), were exposed to water effluent containing parasite stages. Humoral factors (total IgM and IgT, specific anti-E. leei IgM, total serum peroxidases), histopathology and gene expression were analysed. Results showed that SUR maintained high levels of specific anti-E. leei IgM (up to 16 months), expressed high levels of immunoglobulins at the intestinal mucosa, particularly the soluble forms, and were resistant to re-infection. Their acquired-type response was complemented by other immune effectors locally and systemically, like cell cytotoxicity (high granzyme A expression), complement activity (high c3 and fucolectin expression), and serum peroxidases. In contrast to NAI, SUR displayed a post-inflammatory phenotype in the intestine and head kidney, characteristic of inflammation resolution (low il1β, high il10 and low hsp90α expression).

 

Check out all ParaFishControl publications here

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NEW ParaFishControl article "Methacarn preserves mucus integrity and improves visualization of amoebae in gills of Atlantic salmon (Salmo salar L.)"

Methacarn preserves mucus integrity and improves visualization of amoebae in gills of Atlantic salmon (Salmo salar L.). Journal of Fish Diseases. doi: 10.1111/jfd.12988

Two aqueous fixation methods (modified Davidson's solution and modified Davidson's solution with 2% (w/v) Alcian blue) were compared against two non‐aqueous fixation methods (methacarn solution and methacarn solution with 2% (w/v) Alcian blue) along with the standard buffered formalin fixation method to (a) improve preservation of the mucous coat on Atlantic salmon, Salmo salar L., gills and (b) to examine the interaction between the amoebae and mucus on the gill during an infection with amoebic gill disease. Aqueous fixatives demonstrated excellent cytological preservation but failed to deliver the preservation of the mucus when compared to the non‐aqueous‐based fixatives; qualitative and semi‐quantitative analysis revealed a greater preservation of the gill mucus using the non‐aqueous methacarn solution. A combination of this fixation method and an Alcian blue/Periodic acid–Schiff staining was tested in gills of Atlantic salmon infected with amoebic gill disease; lectin labelling was also used to confirm the mucus preservation in the methacarn‐fixed tissue. Amoebae were observed closely associated with the mucus demonstrating that the techniques employed for preservation of the mucous coat can indeed avoid the loss of potential mucus‐embedded parasites, thus providing a better understanding of the relationship between the mucus and parasite.

Check out all ParaFishControl publications here

NEW ParaFishControl article "Salmon louse rhabdoviruses: Impact on louse development and transcription of selected Atlantic salmon immune genes"

Salmon louse rhabdoviruses: Impact on louse development and transcription of selected Atlantic salmon immune genes. Developmental & comparative immunology. doi: 10.1016/j.dci.2018.04.023

Recently, it has been shown that the salmon louse (Lepeophtheirus salmonis) is commonly infected by one or two vertically transmitted Lepeophtheirus salmonis rhabdoviruses (LsRVs). As shown in the present study, the viruses have limited effect on louse survival, developmental rate and fecundity. Since the LsRVs were confirmed to be present in the louse salivary glands, the salmon cutaneous immune response towards LsRV positive and negative lice was analyzed. In general, L. salmonis increased the expression of IL1β, IL8 and IL4/13A at the attachment site, in addition to the non-specific cytotoxic cell receptor protein 1 (NCCRP-1). Interestingly, LsRV free lice induced a higher skin expression of IL1β, IL8, and NCCRP-1 than the LsRV infected lice. The inflammatory response is important for louse clearance, and the present results suggest that the LsRVs can be beneficial for the louse by dampening inflammation. Further research is, however; needed to ascertain whether this is a direct modulatory effect of secreted virions, or if virus replication is altering the level of louse salivary gland proteins.

Check out all ParaFishControl publications here

NEW ParaFishControl article "Detection of the intranuclear microsporidian Enterospora nucleophila in gilthead sea bream by in situ hybridization"

Detection of the intranuclear microsporidian Enterospora nucleophila in gilthead sea bream by in situ hybridization. Journal of Fish Diseases. doi: 10.1111/jfd.12993

Enterospora nucleophila is an intranuclear microsporidian responsible for emaciative microsporidiosis of gilthead sea bream (GSB). Its minute size and cryptic nature make it easily misdiagnosed. An in situ hybridization (ISH) technique based on antisense oligonucleotide probes specific for the parasite was developed and used in clinically infected GSB in combination with calcofluor white stain (CW) and other histopathological techniques. The ISH method was found to label very conspicuously the cells containing parasite stages, with the signal concentrating in merogonial and sporogonial plasmodia within the infected cell nuclei. Comparison with CW demonstrated limited ISH signal in cells containing mature spores, which was attributed mostly to the scarcity of probe targets present in these stages. Although spores were detected in other organs of the digestive system as well as in the peripheral blood, proliferative stages or parasite reservoirs were not found in this work outside the intestines. The study demonstrated a frequent disassociation between the presence of abundant spores and the intensity of the infections as determined by the parasite activity. The ISH allows confirmatory diagnosis of GSB microsporidiosis and estimation of infection intensity and will be a valuable tool for a more precise determination of parasite dissemination pathways and pathogeny mechanisms.

Check out all ParaFishControl publications here