Fisheries and aquatic resources--fish health

2008 ◽  
Author(s):  
Frank Panek
Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 460
Author(s):  
Tawni B. Riepe ◽  
Victoria Vincent ◽  
Vicki Milano ◽  
Eric R. Fetherman ◽  
Dana L. Winkelman

Efforts to advance fish health diagnostics have been highlighted in many studies to improve the detection of pathogens in aquaculture facilities and wild fish populations. Typically, the detection of a pathogen has required sacrificing fish; however, many hatcheries have valuable and sometimes irreplaceable broodstocks, and lethal sampling is undesirable. Therefore, the development of non-lethal detection methods is a high priority. The goal of our study was to compare non-lethal sampling methods with standardized lethal kidney tissue sampling that is used to detect Renibacterium salmoninarum infections in salmonids. We collected anal, buccal, and mucus swabs (non-lethal qPCR) and kidney tissue samples (lethal DFAT) from 72 adult brook trout (Salvelinus fontinalis) reared at the Colorado Parks and Wildlife Pitkin Brood Unit and tested each sample to assess R. salmoninarum infections. Standard kidney tissue detected R. salmoninarum 1.59 times more often than mucus swabs, compared to 10.43 and 13.16 times more often than buccal or anal swabs, respectively, indicating mucus swabs were the most effective and may be a useful non-lethal method. Our study highlights the potential of non-lethal mucus swabs to sample for R. salmoninarum and suggests future studies are needed to refine this technique for use in aquaculture facilities and wild populations of inland salmonids.


Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 285
Author(s):  
Cynthia R. Adams ◽  
Vicki S. Blazer ◽  
Jim Sherry ◽  
Robert Scott Cornman ◽  
Luke R. Iwanowicz

Hepatitis B viruses belong to a family of circular, double-stranded DNA viruses that infect a range of organisms, with host responses that vary from mild infection to chronic infection and cancer. The white sucker hepatitis B virus (WSHBV) was first described in the white sucker (Catostomus commersonii), a freshwater teleost, and belongs to the genus Parahepadnavirus. At present, the host range of WSHBV and its impact on fish health are unknown, and neither genetic diversity nor association with fish health have been studied in any parahepadnavirus. Given the relevance of genomic diversity to disease outcome for the orthohepadnaviruses, we sought to characterize genomic variation in WSHBV and determine how it is structured among watersheds. We identified WSHBV-positive white sucker inhabiting tributaries of Lake Michigan, Lake Superior, Lake Erie (USA), and Lake Athabasca (Canada). Copy number in plasma and in liver tissue was estimated via qPCR. Templates from 27 virus-positive fish were amplified and sequenced using a primer-specific, circular long-range amplification method coupled with amplicon sequencing on the Illumina MiSeq. Phylogenetic analysis of the WSHBV genome identified phylogeographical clustering reminiscent of that observed with human hepatitis B virus genotypes. Notably, most non-synonymous substitutions were found to cluster in the pre-S/spacer overlap region, which is relevant for both viral entry and replication. The observed predominance of p1/s3 mutations in this region is indicative of adaptive change in the polymerase open reading frame (ORF), while, at the same time, the surface ORF is under purifying selection. Although the levels of variation we observed do not meet the criteria used to define sub/genotypes of human and avian hepadnaviruses, we identified geographically associated genome variation in the pre-S and spacer domain sufficient to define five WSHBV haplotypes. This study of WSHBV genetic diversity should facilitate the development of molecular markers for future identification of genotypes and provide evidence in future investigations of possible differential disease outcomes.


Toxics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 79
Author(s):  
Inge Werner ◽  
Anke Schneeweiss ◽  
Helmut Segner ◽  
Marion Junghans

This study assessed the acute and chronic risk of pesticides, singly and as mixtures, for fish using comprehensive chemical data of four monitoring studies conducted in small- and medium-sized streams of Switzerland between 2012 and 2018. Pesticides were ranked based on single substance risk quotients and relative contribution to mixture risk. Concentrations of the pyrethroid insecticides, λ-cyhalothrin, cypermethrin and deltamethrin, and the fungicides, carbendazim and fenpropimorph, posed acute or chronic single substance risks. Risk quotients of eighteen additional pesticides were equal or greater than 0.1, and thirteen of those contributed ≥30% to mixture risk. Relatively few substances dominated the mixture risk in most water samples, with chronic and acute maximum cumulative ratios never exceeding 5 and 7, respectively. A literature review of toxicity data showed that concentrations of several pesticides detected in Swiss streams were sufficient to cause direct sublethal effects on fish in laboratory studies. Based on the results of our study, we conclude that pesticides detected in Swiss streams, especially pyrethroid insecticides, fungicides and pesticide mixtures, pose a risk to fish health and can cause direct sublethal effects at environmental concentrations. Sensitive life stages of species with highly specialized life history traits may be particularly vulnerable; however, the lack of toxicity data for non-model species currently prevents a conclusive assessment across species.


Author(s):  
Wenche M. Kjæmpenes

Abstract This article investigates, using a sociology of profession approach, why veterinarians and aqua medicine biologists share jurisdiction in fish health in Norway. I use a five-actor framework to highlight key events in the development of the Norwegian model for inter-professional and cross-sectoral collaboration in fish health. Veterinarians were initially the only profession involved in fish health. However, in the late 1980s, the Norwegian aquaculture industry suffered great losses due to significant disease outbreaks. Lack of scientific knowledge about the disease causing the outbreaks, Hitra disease, and lack of veterinary capacity to cope with the problem resulted in a situation in which veterinarians continued, as an early response to the disease, to use antibiotic-based therapies. The marine science milieu, with support from the aquaculture industry, instituted a vaccine solution to the endemic Hitra disease in 1987. This scientific breakthrough had major impacts on combatting fish diseases and on the further development of vaccines. New vaccine solutions for other diseases, such as furunculosis, were developed by international and multidisciplinary collaboration. Over a 7-year period, the use of antibiotic-based therapy was dramatically reduced. The control of fish diseases is aquaculture’s X factor, and without these vaccine solutions and regulation regimes, the story of Norwegian aquaculture could have been different. The successful development of the Hitra disease vaccine enabled the marine science milieu at the University of Bergen and the University of Tromsø to establish a new programme of education for aqua medicine biologists based on their own scientific knowledge base. However, their struggle for shared jurisdiction, including the right to prescribe veterinary medicine, lasted nearly 20 years. In 2005, veterinary legislation was amended, and in addition to medical doctors, dentists and veterinarians, aqua medicine biologists, as the fourth profession in Norway, gained the right to prescribe medical products. I argue that the experience in Norway, where professionals from two different sectors share jurisdiction and work side by side in fish health, is worth examining as a model for organizing inter-professional and cross-sectoral collaboration.


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