Risk factors for infection with and losses due to important parasites in gilthead sea bream and European sea bass aquaculture

Trabajo presentado en la 18th International Conference on Diseases of Fish and Shellfish, celebrada en Belfast, del 4 al 8 de septiembre de 2017The identification of risk factors for parasite introduction into and amplification within fish farms is crucial in order to design effective biosecurity and parasite control management strategies. Currently, there is a substantial lack of knowledge about such risk factors. A structured review of the available literature on risk factors for selected parasites was undertaken with the aim to bring together relevant knowledge on characteristics of host and parasite biology and risk factors for infection and amplification of parasites on fish farms. This process helped to assess the level of data available and identification of data gaps. Questionnaires were designed to provide parameter estimates on the relevance of risk factors for initial parasite infection and risk factors for infection causing impact for infection of gilthead seabream (Sparus aurata) with Enteromyxum leei and Sparicotyle chrysophrii, and of European seabass (Dicentrarchus labrax) with Ceratothoa oestroides and Amyloodinium ocellatum. Separate questionnaires were developed for each of parasite. Highly experienced experts were then invited to participate in a two-stage consultation process: participation in an online questionnaire, followed by a physical meeting. The responses obtained provide quantitative estimates for the relevance of risk routes of infection with the respective parasites, the relevance of management procedures for reducing or increasing mortality due to parasite infection, relevance of environmental factors, such as water exchange rate. Examples of risk factors that were relevant for development of infection causing impact were frequency of removal of mortalities from rearing units, number of cage farm sites in a production area. Management procedures that were identified to significantly reduce losses are separation of year classes during production, and fallowing. Furthermore, important quantitative estimates of impacts of parasite infection on aquaculture production in terms of delay in reaching harvest size or cumulative mortality during certain phases of production were obtained. The literature reviews and outcomes from the expert consultations are now forming the basis for planning further data collection through field studies. The information brought together will also feed into the development of biosecurity and integrated pest management strategies and assessments of the most economic management strategies of parasite infections.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 634429.Peer reviewe

Main parasitic infections in gilthead seabream and European seabass aquaculture: risk factors from stakeholders' perspective

Understanding of risk factors for parasite introduction and amplification within fish farms is crucial to design effective biosecurity and control management strategies but currently, quantitative data on the relevance of such risk factors is largely absent. We have designed the questionnaires for stakeholders to characterize the risk factors and estimate their relevance for infections causing major economic burden on gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) production: the myxozoan Enteromyxum leei, the monogenean Sparicotyle chrysophrii, the crustacean Ceratothoa oestroides and the dinoflagellate Amyloodinium ocellatum. Twenty-two experts (Belgium, Croatia, Greece, Italy, Norway, and Spain) were invited to participate in an online questionnaire, followed by a physical meeting to discuss the most probable values for parameter estimates. Quantitative estimates were obtained for the relevance of risk routes of parasite spread (e.g., the likelihood of parasite transmission from an infected to an uninfected net cage 5 m away was estimated to be 90% for E. leei), and the relevance of management procedures and environmental factors that may have an impact on the probability of infection to lead to disease (e.g., where mortalities are removed at > 5-day intervals, the likelihood that infection will lead to disease was 30% for S. chrysophrii). These quantitative estimates were appraised, including the delay in reaching harvest size, or cumulative mortality during phases of production, being essential for calculation of the burden of these diseases in aquaculture. The data presented are highly valuable to the development of economically viable biosecurity and specific integrated pest management strategies

Correction to: Main parasitic infections in gilthead seabream and European seabass aquaculture: risk factors from stakeholders’ perspective (Aquaculture International, (2024), 10.1007/s10499-023-01374-3)

Springer No Unnumbered 2024 1 26 0 NonStandardArchiveJournal Unnumbered Regular OpenAccess OpenAccess OpenAccess OpenAccess OpenAccess OpenAccess true BodyRef/PDF/10499_2024_Article_1419.pdf Typeset OnlinePDF Erratum Life Sciences Freshwater & Marine Ecology Zoology Biomedical and Life Sciences false The corresponding author requested to update the 1st author’s affiliation (from Dorchester to London). The updated affiliation 1 is shown below: Department for Environment, Food and Rural Affairs, Aquatic Animal Health Policy, London, UK The original article has been corrected

TargetFish industry forum on DNA vaccination: Where do we stand and what's next?

Maybe most characteristic of the TargetFish1 project, which kicked off some five years ago with 30 partners from 10 EU member states, two associated countries (Norway, Israel) and one international cooperation partner country (Chile), has been the close cooperation between research groups and enterprises; more or less equally represented in this large consortium. In this respect, TargetFish has been revolutionary validating by this close cooperation fundamental knowledge for the development of next generation vaccines and different routes of vaccine administration. TargetFish had the ambition to demonstrate market applicability of improved vaccines or new prototype vaccines that would come forward from the project. Via frequent joint meetings of its partners, be it research group or enterprise, TargetFish aimed to drive vaccine development in an industrial applicable way. This could facilitate adoption of new intellectual property and stimulate the presentation of new fish vaccines on the market. The industry forum has been a platform for a continuing validation of the applied potential of the research outcomes. Workshops were organised at the different EAFP meetings to communicate the validation process to those not directly involved with the project but interested in the fish vaccine market. After a kick-off meeting during the EAFP in Tampere, Finland fours years ago and a second meeting at the EAFP in Las Palmas, Spain, two years ago, at the present EAFP in Belfast, Northern Ireland a final meeting was organised. This report is a summary of the 'Industrial Forum workshop' held at the EAFP in Belfast 2017 and provides a short overview of the highlights presented to, and discussed with, those present and interested in DNA vaccine development, policies and laws, production and delivery routes

Enteromyxum leei in mediterranean gilthead sea bream farms: how much is out there?

Trabajo presentado en la International Conference & Exposition Aquaculture Europe, celebrada en Funchal, Maderia (Portugal) del 04 al 07 de octubre de 2021.[Introduction]: Enteromyxum leei (Myxozoa) is an important pathogen of gilthead seabream (GSB), Sparus aurata and other Sparidae fish cultured in the Mediterranean. In GSB, E. leei induces chronic enteritis followed by anorexia, cachexia, and even death. It can cause significant growth delay and mortality in marine cage farms as well as land-based mariculture systems. Water temperature and water recirculation are critical risk factors in the contagion and onset of enteromyxosis (Palenzuela et al., 2006, Sitjà-Bobadilla and Palenzuela 2012). However, the relevance of other risks factors like farm management practices, and the epidemiological situation in gilthead sea bream farms, have not been thoroughly determined. In this study, a risk assessment questionnaire and cross-sectional epidemiological study was designed to get insights in the distribution and incidence of E. leei in more than 50 Mediterranean and Atlantic GSB farms throughout Western Europe.[Methods]: A questionnaire for GSB cage farms was designed to ascertain information about farm background and self-awareness of risk relative to E. leei infection, as well as details on the facilities, production and farm management routines. In addition, the farms were invited to participate in a cross-sectional targeted epidemiological survey to test the presence of the parasite in their stock. The participant farms were recruited by local expert pathologists and consultants acting as nodes in each geographical region, and the samples and questionnaires were coded and studied blindly. For those farms participating in the biological sampling, a protocol was submitted to sample one batch of fish at harvest time. The sampling was designed to detect prevalence higher than 9.5% with a 95% confidence. The intestinal rectal ampoules (portion with maximum predictive value for E. leei detection in GSB) were taken from at least 30 randomly selected fish during routine harvest from one or several cages. For the validation of the survey protocol, a land-based farm which is enzootic for the parasite was enrolled in the study and two different GSB lots were sampled as positive controls. The samples were fixed in 80-90 º Ethanol and paired into 15 tubes, which were shipped to the central diagnosis laboratory at IATS-CSIC. The routine procedures for diagnosis of E. leei consist of a SYBR-green qPCR test with primers specific for the parasite against a standard curve containing known numbers of copies of the target gene. Upon reception at the laboratory the samples were individually processed and homogenised. DNA was extracted from an aliquot using a robotic system, its quantity and quality were evaluated, and samples were tested by qPCR at two different dilutions. They were considered positive when the cycle threshold (Ct) was <38.[Results and Discussion]: A total of 45 cage farms from Croatia (12), Greece (12), Italy (13), Spain (7) and Malta (1) completed the questionnaires. Among them, 32% declared to have previous records of the parasite: 11 of them at some point in the last 5 years, 3 in the most recent production cycle, and 4 having infections recurrently. Among the farms with previous records, the disease was considered not relevant in 7, controllable in 7, and problematic in 4 sites. A total of 40 cage farms sent a total of 1330 fish biological samples which were tested by qPCR. The results show that the infection persists unnoticed at many farms (Table 1), Famers were most aware of the presence of the infection in Greek waters. On the contrary, Croatian farmers were unanimously unaware of the presence of the parasite although it was detected at most of the tested sites. Prevalence of infection was generally lower in sites where the infection was not believed to be present, suggesting that low level infections, although widespread, do not cause any noticeable problems at many farms. All countries sampled had the infection, and the only countries with farms in which the infection was not detected were Croatia and Italy. Prevalence was highest on average in Greece (Table 2). The statistical analysis considered prevalence against farm level factors as well as batch level factors. For most variables no significant effect was observed. At a farm level, farms removing mortalities more frequently, and those with stronger water exchange have a lower prevalence of infection. The number of hatcheries supplying the farm and the size of fish at harvest showed the strongest positive association with prevalence. Larger farms with higher numbers of cages, cage sizes and annual production tended to have higher prevalence. At the batch level, fish which had experienced highest minimum temperatures and those introduced to the cages at larger sizes had higher prevalence, whereas shorter times on the farm and higher specific growth rates were associated with lower prevalence

TargetFish - Targeted disease prophylaxis in European fish farming

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