Source: MISSISSIPPI STATE UNIV submitted to NRP
MANAGING CATFISH HEALTH IN AQUACULTURE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1021047
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Dec 3, 2019
Project End Date
Sep 10, 2023
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
MISSISSIPPI STATE UNIV
(N/A)
MISSISSIPPI STATE,MS 39762
Performing Department
Delta Research & Extension Center
Non Technical Summary
In the United States, pond production of catfish ranks as the leading aquaculture species. The 2013 Census of Aquaculture reported 605 catfish farms involved in the sale of food size fish primarily in the states of Alabama, Arkansas, and Mississippi and having sales valued at $354 million. Health management strategies, technologies, and bio-security plans that are environmently safe and are necessary to help mitigate disease-related losses. There is presently a lack of validated technologies for early and rapid detection of pathogens, disease prevention, and treatment of diseases in catfish aquaculture, which has hindered the growth of the industry. Validated diagnostic tools for use in production systems to detect the disease agents in a rapid fashion are needed. In addition to the need for diagnostics, developing effective control strategies and therapeutants to manage disease is a priority, given only a few drugs are available for the treatment of sick fish. Research within this project will lead to the development of molecular based diagnostic tools to monitor potential emergent pathogens, optimized vaccination strategies for control of bacterial infections, and an improved understanding of disease processes and disease risk factors in commercial catfish aquaculture. Economic assessment of disease losses and disease management strategies will help producers make more cost efficient management decisions to improve farm profitability.
Animal Health Component
80%
Research Effort Categories
Basic
15%
Applied
80%
Developmental
5%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3113710104020%
3113710109015%
3113710110115%
3113710117010%
3113710110015%
3113710111015%
3113710301010%
Knowledge Area
311 - Animal Diseases;

Subject Of Investigation
3710 - Catfish;

Field Of Science
1040 - Molecular biology; 1090 - Immunology; 1101 - Virology; 1100 - Bacteriology; 1110 - Parasitology; 3010 - Economics; 1170 - Epidemiology;
Goals / Objectives
In the United States, pond production of catfish ranks as the leading aquaculture species. The 2013 Census of Aquaculture reported 605 catfish farms involved in the sale of food size fish primarily in the states of Alabama, Arkansas, and Mississippi and having sales valued at $354,337,000. Health management strategies, technologies, and bio-security plans that are environmentally safe and are necessary to help mitigate disease-related losses. There is presently a lack of validated technologies for early and rapid detection of pathogens, disease prevention, and treatment of diseases in catfish aquaculture, which has hindered the growth of the industry. Validated diagnostic tools for use in production systems to detect the disease agents in a rapid fashion are needed. In addition to the need for diagnostics, developing effective control strategies and therapeutants to manage disease is a priority, given only a few drugs are available for the treatment of sick fish. Further research will develop molecular based diagnostic tools used in to monitor potential emergent pathogens, optimize vaccination strategies for control of bacterial infections, determine the epidemiology of priority infectious diseases and assess costs and benefits of disease management strategies in hybrid and channel catfish aquaculture.Objective 1: Identify emergent pathogens in catfish aquaculture and develop disease diagnostic methodologies. his objective will identify potential emergent pathogens impacting channel and hybrid catfish and develop molecular tests for pathogen identification from clinical and environmental samples. Molecular tests and immunological procedures will be used in field monitoring studies to evaluate pathogen loading rates and exposure levels within pond populations and identify potential disease vectors and disease transmission mechanisms. Koch's postulates or River's postulate will be used to establish causative relationships between putative emergent pathogens and disease.Objective 2: Optimize treatments and management strategies to minimize diseases in catfish aquaculture. Research will optimize a live-attenuated E. ictaluri vaccine currently being administered to catfish fingerlings and evaluate Cross protective potential against a closely related pathogen, E. piscicida. Work within the scope of this research objective will identify risk factors associated with bacterial and parasitic diseases, and physiological response of channel and hybrid catfish to digenetic trematodes.Objective 3: Epidemiology of infectious diseases in catfish aquaculture and economic evaluations of disease management. Research will identify risk factors associated with A. hydrophila epizootics on commercial farms and evaluate disease potential of CCV variants and a recently characterized blue catfish virus in channel and hybrid catfish. Economic analysis of an experimental ESC vaccine will be conducted in commercially raised catfish. Efficacy and cost benefit analysis will be evaluated in commercial fingerling and foodfish production systems.
Project Methods
All trials will be conducted with established protocols using sound experimental design subject to parametric statistical analysis. Objective 1: Identify emergent pathogens in catfish aquaculture and develop disease diagnostic methodologies.1.1 Diagnostic cases submitted through the Aquatic Research and Diagnostic Laboratory (MSU-CVM, Stoneville, MS) will be used to track changes in disease trends, identify emergent pathogens, and assess antibiotic resistance patterns. Potential emergent pathogens will be genetically characterized and documented as pathogens of catfish through fulfillment of Koch's or River's postulates. Assembled genomes of newly identified pathogens will be mined for discriminatory gene targets that can be exploited by quantitative PCR and provide a rapid confirmatory diagnostic test in tissue and environmental samples.1.2. Recently Yersinia ruckeri, isolated from diseased hybrid catfish, and a non-toxigenic strain of vibrio cholera, isolated from hatchery fry have been identified as potential emergent pathogens. Hybrid and channel catfish will be exposed by IP injection to archived cultures of Y. ruckeri and V. cholera. Moribund fish will be subjected to diagnostic evaluation and recovered bacteria will be PCR confirmed to fulfill Koch's postulates. In addition, two channel catfish variants have been identified along with a blue catfish herpesvirus isolated from a diseased blue catfish. Virus will be propagated in tissue culture and used to infect fish. Virus will be re-isolated in tissue culture and confirmed by PCR sequencing to fulfill River's postulates.Objective 2: Optimize treatments and management strategies to minimize diseases in catfish aquaculture.2.1.A. An experimental live attenuated E. ictaluri vaccine and method of oral delivery has been developed an extensively field tested. Since the vaccine is delivered orally and daily feeding activity can vary, reapplication may be necessary to ensure adequate vaccine coverage. Vaccination trials will be conducted to determine vaccine safety in fish receiving multiple vaccine dosages. Fish will be fed the vaccine feed mixture once or on consecutive days and challenge with a wild type isolate to assess vaccine efficacy. Vaccine safety will be determine by the occurrence of post vaccination mortality. If adverse vaccine reactions to over dosing does not occur, the study will be repeated in experimental ponds.2.1.B. Preliminary work indicates the experimental ESC vaccine cross protects against a closely related bacterial pathogen, E. piscicida. However, recently at least 5 genetic E. piscicida variants have been identified which could alter the cross-protective potential of the vaccine. Fish will be vaccinated by oral delivery and later challenged with wild-type E. ictaluri and E. piscicida. Cross reactive serology and protection against infection will be used to assess the cross-protection potential of the E. ictaluri vaccine against identified E. piscicida variants.2.2.A. The myxozoan parasite H. ictaluri is the causative agent of proliferative gill disease in channel catfish. Recent work has demonstrated hybrid catfish suffer from the acute stages of infection but serve as a dead end host for the parasite, preventing further propogation of the parasite within the pond environment. However, in some instances, PGD is developing in hybrid catfish production systems. This suggests that there are other myxozoan species causing PGD or the presence of other disease vectors. Myxozoan actinospores will be collected from D. digitata isolated from benthic sediments of ponds with active PGD and used in infectivity challenges with channel and hybrid catfish. Fish will be sampled for identification of pre-sporogonic stages characteristic of H. ictaluri induced PGD and for the presence of mature myxospores. Mature myxospores will be sequenced to identify the presense non-H. ictaluri life stages causing PGD.2.2.B. Work done with other myxozoan species suggests there is a intraspecific variability of the oligochaete host with some lineages being refractory to myxozoan infections. Oligochaetes will be collected from channel and hybrid catfish ponds with and without active PGD outbreaks in the spring of the year during periods of peak PGD incidence. Myxozoan positive and myxozoan negative oligochaetes will be characterized by 16S mtRNA sequencing to determine relationships, if any, to 16S mtRNA sequence types and myxozoan actinsopore release in Dero digitata.Objective 3: Epidemiology of infectious diseases in catfish aquaculture and economic evaluations of disease management. 3.1. Spatial and temporal analysis of aAh isolates from catfish producing states in the southeastern United States will be evaluated for genetic variation. This work will genotype historical archived aAh isolates using previously established PCR protocols to identify geographical or temporal relationships among the two variants. The ARDL repository contains over 200 archived catfish isolates from the southeastern U.S., as well as non-catfish isolates from other states. In addition, new isolates will be added to the data set as they become available. Currently two distinct aAh variants have been identified in commercially raised hybrid and channel catfish (Rasmussen-Ivey et al. 2016), one of which is prominent in Mississippi (MS-aAh), while the other appears to be endemic to west Alabama (AL-aAh) (Griffin, unpublished data). Challenge trials will be conducted to determine pathological and serological differences between genetic variants in channel and hybrid catfish. Vaccination trials using an experimental live attenuated vaccine developed by Auburn University will be evaluated against each genetic variant. 3.2. Environmental and community data will be used to modeling programs to identify risk factors associated with aAh infections in catfish aquaculture. Pond models will be created using a combination of R Studio v 0.99.903 (R Development Core Team) and STELLA 10.0.2 (ISEE Systems). Logistic regression will be used to assess associations between dichotomous outcomes such as vAh outbreak occurrence. Generalized linear mixed models (GLMMs) will be fitted, using random effects to account for dependence of multiple measurements from the same pond and variability among farms.Graphical modeling will occur using STELLA modeling software. STELLA allows for visual modeling of systems through the use of flows and stock variables. Environmental and community data will be coupled with production data (i.e. feeding rates, stocking densities, etc.) collected from the literature and participating farms. Positive vAh outbreak scenarios will also undergo a sensitivity analysis to evaluate the importance of each predictive variable.3.3. Economic evaluation of a live attenuated E. ictaluri vaccine will be conducted on commercial operations involving participating farms and over 350 million fish. A partial-budget analysis that quantifies the economic cost and benefits of vaccinating channel and hybrid catfish on commercial fingerlings operations will be conducted to evaluate the net economic benefit of ESC vaccination on catfish fingerling operations. Whole-farm mathematical programing will be employed to estimate the economic effects of vaccination on catfish operations that integrates hatchery, fingerling, and foodfish operations. The models will be developed to capture the resource-use efficiency arising from vaccination improvements in fingerling-production phase. Profit-maximizing linear-programming models will be developed to obtain the optimal allocation of land, fingerlings, feed, capital etc.

Progress 12/03/19 to 09/30/20

Outputs
Target Audience:The goal of research in this project is to address high priority, industry-identified issues to increase production efficiencies and profitability of aquaculture in the southeastern United States. The target audience for new information and technologies developed in this project is the American farmer raising aquaculture products, with special emphasis on catfish farmers. Farmers use management practices developed from this project to improve production efficiencies. Knowledge developed in this project is passed to user groups through a formal network of extension program specialists, producer workshops, conferences, seminars, and newsletters. Investigators also deliver this knowledge to other scientists and students of aquaculture through professional meetings, peer-reviewed scientific publications, and lectures. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?The goal of research in this project is to address high priority, industry-identified issues to increase production efficiencies and profitability of aquaculture in the United States. Knowledge developed from this project was disseminated to user groups through Extension workshops, conferences, seminars, and newsletters. Investigators also delivered this knowledge to other scientists and students of aquaculture through professional meetings, peer-reviewed scientific publications, and lectures What do you plan to do during the next reporting period to accomplish the goals?Work will concentrate on continued improvements in fish health and the development and refinement of management strategies to minimize the impact of parasitic, bacterial, and viral diseases affecting catfish aquaculture. The Aquatic Research and Diagnostic Laboratory will continue to provide research support and track industry wide changes in disease trends. Proliferative gill disease, caused by the myxozoan Henneguya ictaluri, is arguably the most important parasitic disease of cultured catfish. A metagenomic approach has been validated for assessment of mxyozoan community structures in diseased fish and environmental samples. This approach will be used to evaluate the influence of host species on myxozoan population dynamics in catfish production systems and evaluate the feasibility of crop rotation between hybrid and channel catfish to minimize myxozoan communities causing disease. Work will continue to develop more effective and safer treatments for controlling snail populations in catfish production systems as a means of minimizing production losses associated with the digenetic trematode Bolbophorus damnificus. In support of this approach, pond studies will evaluate multiple low dose copper sulfate treatments on production. A novel herpes virus was isolated from blue catfish and presents a threat as an emergent pathogen as blue catfish production has increased resulting from increased hybrid catfish production. Molecular diagnostic assays have been developed to differentiate channel catfish virus from blue catfish alloherpesvirus and will be used track viral prevalence in channel, blue and channel x blue hybrid catfish. An inactivated form of the virus is being evaluated as a potential vaccine. Archived bacterial isolates, Flexibacter columnare and Edwardsiella piscicida, will be attenuated and evaluated as candidates for vaccine development. Information generated from these efforts will be transferred to catfish producers and other fish health specialist through workshops, scientific publications and meetings, and trade journals.

Impacts
What was accomplished under these goals? Objective 1: Identify emergent pathogens in catfish aquaculture and develop disease diagnostic methodologies The Aquatic Research and Diagnostic Laboratory (ARDL) provides a mechanism for monitoring disease trends and diagnostic support for state and regional research programs. Increased use of hybrid catfish has shifted the predominant disease agents within the industry due to differential host susceptibility to parasitic and bacterial pathogens. Primary changes are associated with increased occurrence of Edwardsiellosis associated with Edwardsiella piscicida and decreased incidence of proliferative gill disease (PGD) caused by the myxozoan Henneguya ictaluri. Research has demonstrated hybrid catfish are a dead-end host in the H. ictaluri life cycle but have increased susceptibility to Edwardsiella piscicida. Since 2013, hybrids comprise roughly 50% of total diagnostic submissions to the ARDL, but account for >90% of E. piscicida cases. Similarly, in 2019, hybrids accounted for only <33% of PGD cases, reducing the total number of PGD cases by nearly 50%. Vibriosis has been diagnosed as the cause of chronic mortality in catfish hatcheries and species of ornamental fish. Isolates have been genetically identified as Vibrio cholerae raising concerns over zoonotic potential. Genetic sequencing and analysis of ~70 suspected V. spp. isolates demonstrated the absence of the toxigenic gene (CTX) typically associated with human illness. It is hypothesized that V. spp. outbreaks are a result of overcrowding and diminished environmental conditions and losses can be controlled with improved management. In 2016 and again in 2017, Yersinia ruckeri was isolated from diseased hybrid catfish raising concerns to its potential as an emergent pathogen in hybrid catfish. Isolates have been archived, genetically characterized and used to fulfill Koch's postulates. While this data demonstrates Y. ruckeri can serve as a pathogen of catfish, there have been no subsequent reports of Y. ruckeri cases in cultured catfish and remains a pathogen of minimal concern in catfish aquaculture. A variant of channel catfish herpesvirus was isolated from blue catfish and described as blue catfish alloherpesvirus. Genome sequencing followed by fulfilment of River's Postulates identified the isolate as a new herpesvirus with disease potential in blue catfish. The virus was inoculated on established fish cell lines derived from members of the Ictaluridae, Cyprinidae, Centrarchidae, and Clariidae. Viral replication was restricted to cell lines from the family Ictaluridae. Fish age, fish type and water temperature were shown to affect mortality in laboratory challenges. Infected fish revealed inflamed spleens with severe erythrophagia. Objective 2: Optimize treatments and management strategies to minimize disease in catfish aquaculture An orally delivered, live attenuated E. ictaluri vaccine, developed through previous CRIS projects, was shown effective in experimental and commercial field trials. Oral delivery presents a limitation related to poor feed responses which would require re-application of the vaccine, potentially compromising vaccine safety. To this end, multiple vaccine applications were investigated, which did not result in increased morbidity or mortality in laboratory and pond trials. Furthermore, acute oxygen deprivation before or after vaccine application did not compromise vaccine safety or efficacy. These data, along with dose titration trials, revealed no adverse reactions to vaccination when delivered at 25X the target dose, indicates a high level of safety under laboratory and field conditions. Preliminary observations indicate the live attenuated Edwardsiella ictaluri vaccine currently in commercial use also provides protection against the closely related bacterial pathogen E. piscicida. This led to in-depth investigations into the cross-protective potential of the vaccine. Isolates, recovered from diseased catfish, were genetically characterized revealing five discrete genetic groups which correlated with virulence gene profiles. Each genetic group demonstrated increased virulence in hybrids over channel catfish. In laboratory trials, vaccination against E. ictaluri was shown to protect fish against all E. piscicida genetic groups. Work is being conducted to increase vaccine efficacy in hybrid catfish. Objective 3: Epidemiology of infectious diseases in catfish aquaculture and economic evaluation of disease management. Since 2009, an emergent strain of Aeromonas hydrophila has been identified as the cause of substantial economic losses in catfish aquaculture. Genetic characterization of isolates collected from discrete geographic regions revealed a temporal and spatial shift in A. hydrophila haplotypes. These new strains possessed virulence factor profiles that varied from the original emergent strain. Analysis of 12 environmental factors in healthy and outbreak ponds yielded no consistent mechanism or risk factor associated with atypical A. hydrophila outbreaks. Occupancy models estimate that 10% of the resident fish population in ponds are harboring the pathogen, with prevalence as high as 60% in some ponds, despite no overt signs of distress or disease. The presence of an asymptomatic carrier state provides a mechanism allowing for environmental persistence. Under our previous CRIS project, a live attenuated E. ictaluri vaccine and mechanized delivery systems for oral delivery in ponds was developed and commercially licensed in 2018. Over the past three years vaccination was shown to increase survival, yield and feed conversion resulting in increased economic returns. Industry adoption has increased from 10 producers covering 2,423 acres in 2018 to 14 producers covering 3,487 acres in 2020. To date, most all hybrid and catfish fingerlings produced in Mississippi and Arkansas are vaccinated during the fingerling stage of production, which serve as the primary supply of catfish fingerlings across the southeastern United States. Proliferative gill disease, caused by the myxozoan Henneguya ictaluri, is arguably the most important parasitic disease of cultured catfish. A metagenomic approach has been validated for assessment of mxyozoan community structures and will be used to evaluate the influence of host species on myxozoan population dynamics in catfish production systems. Preliminary analysis of pond water demonstrates variability in predominant myxozoan species in channel and hybrid catfish monoculture systems, revealing suppression of H. ictaluri in hybrid monoculture ponds. Analysis also revealed the existence of multiple undescribed myxozoan taxa present in catfish production systems. Rotation between hybrid and channel catfish monoculture appears to be an effective strategy for preventing the continued buildup of parasitic actinospore resulting in morbidity and mortality. The mitochondrial genome of Dero digitata has been sequenced and gene targets are being assessed for utility in evaluating genetic variation among D. digitata populations to determine any genotype associations with PGD outbreaks. Similarly, the mitochondrial genomes of Planorbella trivolvis and Biomphalaria havanensis snails have been sequenced to identify genes that can be exploited by PCR to detect the presence of snails in catfish ponds using eDNA methodologies previously established at NWAC. The trematode, Bolbophorus damnificus, causes significant losses in US catfish aquaculture. Little is known regarding the prevalence of infected snail hosts during outbreaks. Host snails (n = 8,159) were collected from 14 catfish production ponds with B. damnificus activity in Mississippi. Prevalence of B. damnificus infected snails was typically <3%, indicating numbers of infected snails during outbreaks are low and mitigation efforts may be successful simply by reducing snail numbers and not require complete eradication.

Publications

  • Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Aarattuthodiyil, S., Griffin, M.J., Greenway, T.E., Khoo, L.H., Byars, T.S., Lewis, M., Steadman, J., Wise, D.J. 2020. An orally delivered, live-attenuated Edwardsiella ictaluri vaccine efficiently protects channel catfish fingerlings against multiple Edwardsiella ictaluri field isolates. Journal of the World Aquaculture Society, Journal of the World Aquaculture Society. 51(6), 1354-1372
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Aarattuthodiyil, S., Wise, D., Byars, T., Lucas, P., Li, M. 2019. Effects of Azomite- and Sea Salt-Supplemented Diets on Growth, Feed Conversion Efficiency, Survival, and Resistance against Edwardsiella ictaluri in Channel Catfish Fingerlings North American Journal of Aquaculture, 81 (4), pp. 438-444.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Griffin, M.J., Ware, C., Rosser, T.G., Woodyard, E.T., Mischke, C.C., Byars, T.S., Wise, D.J. 2020. Monoculture of ? channel (Ictalurus punctatus) � ? blue (I. furcatus) hybrid catfish mitigates proliferative gill disease caused by Henneguya ictaluri (Cnidaria: Myxobolidae) in catfish aquaculture ponds. Journal of the World Aquaculture Society, 51 (3), pp. 729-739.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Griffin, M.J., Greenway, T.E., Byars, T.S., Ware, C., Aarattuthodiyil, S., Kumar, G., Wise, D.J. Cross-protective potential of a live-attenuated Edwardsiella ictaluri vaccine against Edwardsiella piscicida in channel (Ictalurus punctatus) and channel � blue (Ictalurus furcatus) hybrid catfish. Journal of the World Aquaculture Society, 51 (3), pp. 740-749.
  • Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Richardson, B.M., Griffin, M.J., Colvin, M.E., Wise, D.J., Ware, C., Mischke, C.C., Greenway, T.E., Byars, T.S., Hanson, L.A., Lawrence, M.L. 2020. Using quantitative polymerase chain reaction (qPCR) and occupancy models to estimate atypical Aeromonas hydrophila (aAh) prevalence in catfish. Aquaculture (accepted)
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Wise, D.J., Greenway, T.E., Byars, T.S., Kumar, G., Griffin, M.J., Khoo, L.H., Chesser, G., Lowe, J. 2020. Validation of Edwardsiella ictaluri oral vaccination platform in experimental pond trials. Journal of the World Aquaculture Society, 51 (2), pp. 346-363.
  • Type: Theses/Dissertations Status: Published Year Published: 2020 Citation: Improved monitoring and decision-making to manage atypical Aeromonas hydrophila in catfish aquaculture ponds. PhD Dissertation Defense: Brad Richardson. May 2020. Major Professor: Mike Colvin, Co-Major Advisor: David Wise, Minor Professor: Ryan Walker, Committee Members: Matthew Griffin, Terrence Greenway, and Charles Mischke.
  • Type: Theses/Dissertations Status: Published Year Published: 2020 Citation: Effects of the trematode Bolbophorus damnificus on channel and hybrid catfish. Masters Thesis: Mackenzie Gunn. May 2020. Major Professor: Peter Allen, Thesis Director: Matthew Griffin, Committee Members: Thomas Rosser and David Wise.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Gunn, M.A., Allen, P.J., Rosser, T.G., Wise, D.J., Khoo, L.H., Griffin, M.J. 2020. Assessment of Bolbophorus damnificus prevalence and cercariae shedding in Planorbella trivolvis populations from catfish aquaculture ponds in Mississippi, USA. Journal of Aquatic Animal Health. DOI: 10.1111/jwas.12756
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Kumar, G., Wise, D., Li, M., Aarattuthodiyil, S., Hegde, S., Rutland, B., Pruitt, S., Griffin, M., Khoo, L. 2020. Effect of understocking density of channel catfish fingerlings in intensively aerated multiple-batch production. Journal of Aquatic Animal Health. DOI: 10.1111/jwas.12733
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Heckman, T.I., Griffin, M.J., Camus, A.C., LaFrentz, B.R., Morick, D., Smirnov, R., Ofek, T., Soto, E. 2020. Multilocus sequence analysis of diverse Streptococcus iniae isolates indicates an underlying genetic basis for phenotypic heterogeneity. Diseases of Aquatic Organisms 141, pp. 53-69.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Pomaranski, E.K., Griffin, M.J., Camus, A.C., Armwood, A.R., Shelley, J., Waldbieser, G.C., Lafrentz, B.R., Garc�a, J.C., Yanong, R., Soto, E. 2020. Description of Erysipelothrix piscisicarius sp. nov., an emergent fish pathogen, and assessment of virulence using a tiger barb (Puntigrus tetrazona) infection model. International Journal of Systematic and Evolutionary Biology, 70 (2), art. no. 003838,
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Rosser, T.G., Woodyard, E.T., Mychajlonka, M.N., King, D.T., Griffin, M.J., Gunn, M.A., L�pez-Porras, A. 2020. Ithyoclinostomum yamagutii n. sp. (Digenea: Clinostomidae) in the great blue heron Ardea herodias L. (Aves: Ardeidae) from Mississippi, USA. Systematic Parasitology 97 (1), pp. 69-82.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Stilwell, J.M., Griffin, M.J., Rosser, T.G., Mohammed, H.H., Sidor, I.F., Camus, A.C. 2020. Insights into myxozoan composition and physiology revealed by histochemical properties of myxospores. Journal of Fish Diseases, 43(5), pp. 583-597.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Woodyard, E.T., Baumgartner, W.A., Rush, S.A., Griffin, M.J., Rosser, T.G. 2020. Pathology associated with Odhneriotrema incommodum infection in wild-caught American alligators Alligator mississippiensis and assessment of potential first intermediate snail hosts. Acta Parasitology (2020) 65 (1), pp. 144-150.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Cunningham, F.L., Hanson-Dorr, K.C., Ford, L., Middleton, D.R., Crain, A., Durst, L., Ware, C., Griffin, M.J., Mischke, C.C., Wan, X.-F., Hanson, L.A. 2020. Environmental factor(s) and animal vector(s) associated with atypical Aeromonas hydrophila abundance and dissemination among channel catfish ponds. Journal of the World Aquaculture Socieity. 51(3), pp. 750-762.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Gibbs, G.D., Griffin, M.J., Mauel, M.J., Lawrence, M.L. 2020. Validation of a quantitative PCR assay for the detection of 2 Flavobacterium columnare genomovars. Journal of Veterinary Diagnostic Investigation. 32(3), pp. 356-362.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Coussens, C. D., E. T. Woodyard, M. A. Gunn, D. T. King, B. Richardson, L. Easter, J. Nguyen, D. J. Wise, M. J. Griffin and T. G. Rosser. The elucidation of the life cycle of a Hysteromorpha sp. in ictalurid catfish production systems in Mississippi, USA. AFS-FHS Virtual Summer Seminar Series. Online. August 7, 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Gunn, M. A., M. J. Griffin, B. Ott, T. G. Rosser, D. J. Wise and P. J. Allen. Comparative mortality and parasite induced anemia in channel Ictalurus punctatus and hybrid I. punctatus x I. furcatus catfish exposed to Bolbophorus damnificus cercariae. AFS-FHS Virtual Summer Seminar Series. Online. May 29, 2020.
  • Type: Theses/Dissertations Status: Published Year Published: 2020 Citation: Intraspecific variability of Edwardsiella piscicida and cross-protective efficacy of a live-attenuated Edwardsiella ictaluri vaccine in channel and channel x blue hybrid catfish. Maters Thesis. Adrian Lopez. May 2020. Major Professor: David Wise, Co-Major Advisor: Suja Aarattuthodiyil, Thesis Director: Matthew Griffin, Committee member: Thomas Rosser.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Heckman, T. I., K. Shahin, M. J. Griffin and E. Soto. Weve got a live one! Generation of a live-attenuated vaccine to piscine streptococcosis. The Conference of Research Workers in Animal Disease. Virtual Meeting. November 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Lopez-Porras, M. J. Griffin, D. J. Wise, G. C. Waldbieser, T. G. Rosser and S. Aarattuthodiyil. Intraspecific variability of Edwardsiella piscicida recovered from farm-raised catfish and cross-protective efficacy of a live-attenuated Edwardsiella ictaluri vaccine. AFS-FHS Virtual Summer Seminar Series. Online. May 22, 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Nguyen, D. T., C. Ware, D. Marancik, M. Griffin and E. Soto. Co-infection of Mycobacterium salmoniphilum and M. chelonae in Chinook salmon (Oncorhynchus tshawytscha). AFS-FHS Virtual Summer Seminar Series. Online. May 22, 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Richardson, B. M., G. C. Waldbieser, C. Ware, M. R. Liles, L. H. Khoo, P. S. Gaunt, L. A. Hanson, M. L. Lawrence, D. J. Wise and M. J. Griffin. Genomic analysis of atypical Aeromonas hydrophila (aAh) from catfish aquaculture in the southeastern United States with evidence of haplotype shifts from diagnostic case submissions. AFS-FHS Virtual Summer Seminar Series. Online. May 14, 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Richardson, B. M., M. J. Griffin, C. C. Mischke, T. E. Greenway, M. E. Colvin, G. C. Waldbeiser, L. A. Hanson, M. L. Lawrence and D. J. Wise. Haplotype shift and genomic variation in atypical Aeromonas hydrophila (aAh) isolates of channel catfish aquaculture in the southeastern US. The Conference of Research Workers in Animal Disease. Virtual Meeting. November 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Richardson, B. M., M. J. Griffin, M. R. Liles and D. J. Wise. Protective effects of prospective vaccine and formalin-killed cultures against atypical Aeromonas hydrophila (aAh) in channel catfish Ictalurus punctatus. The Conference of Research Workers in Animal Disease. Virtual Meeting. November 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stilwell, J., M. Griffin, J. Leary, L. Khoo, and A. Camus. Massive Branchial Henneguyosis: A distinctive myxozoan-induced gill disease of catfish caused by massive interlamellar infections of Henneguya exilis. Annual Meeting of the ACVP. October 30th-November 1st, 2020. Online. Presentation, Poster and Abstract.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stilwell, J., M. Griffin, G. Waldbieser, J. Stanton, C. Ware, J. Leary, L. Khoo, P. Gaunt, D. Wise, and A. Camus. Fish host susceptibility influences myxozoan community composition of proliferative gill disease in catfish aquaculture. Annual Meeting of the ACVP. October 30th-November 1st, 2020. Online. Poster and Abstract.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stilwell, J., M. Griffin, G. Waldbieser, J. Stanton, C. Ware, J. Leary, L. Khoo, D. Wise, and A. Camus. Fish host susceptibility influences myxozoan community composition of Proliferative Gill Disease in catfish aquaculture. Steeve Gigu�re Science of Veterinary Medicine Symposium. October 8th-9th, 2020. Online. Presentation and Abstract.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stilwell, J., M. Griffin, G. Waldbieser, J. Stanton, C. Ware, J. Leary, L. Khoo, P. Gaunt, D. Wise, and A. Camus. Fish host susceptibility influences myxozoan community composition of proliferative gill disease in catfish aquaculture. American Fisheries Society: Fish Health Section Summer Seminar Series. July 31st, 2020. Online. Presentation and Abstract.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stilwell, J., M. Griffin, G. Waldbieser, J. Stanton, C. Ware, J. Leary, L. Khoo, P. Gaunt, D. Wise, and A. Camus. Fish host susceptibility influences myxozoan community composition and diversity in proliferative gill diseases of catfish aquaculture. Annual Meeting of the American Association of Veterinary Parasitologists. June 20th-23rd, 2020. Online. Presentation and Abstract.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stilwell, J., N. Stilwell, A. Camus, C. Ware, T. Rosser, and M. Griffin. Case 19139B: Red-bellied piranha, Pygocentrus nattereri. 37th West Coast Veterinary Pathology Conference. May 1st-2nd, 2020. Online. Presentation and Case Summary.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Venugopalan, L. A. Hanson, D. J. Wise, A. D. Perkins, T. B. Waltzek, G. C. Waldbieser and M. J. Griffin. Investigating IcHV-1 Variants in Channel, blue and channel x blue hybrid catfish. AFS-FHS Virtual Summer Seminar Series. Online. June 26, 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Suja Aarattuthodi and Vandana Dharan. 2020. Channel catfish virus targeted management approaches in catfish aquaculture. Conference of Research Workers in Animal Diseases. Chicago, IL. (Virtual presentation).
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Woodyard, E. T., T. G. Rosser, J. M. Stilwell, A. C. Camus, L. H. Khoo, G. C. Waldbieser, W. W. Lorenze and M. J. Griffin. Molecular and histological characterization of Henneguya postexilis Minchew, 1977 from channel catfish Ictalurus punctatus in Mississippi, USA. AFS-FHS Virtual Summer Seminar Series. Online. July 10, 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Divya Johnson, Matt Griffin, Lester Khoo, Geoff Waldbieser, and Suja Aarattuthodi. 2020. Biological, Molecular and Serological characterization of Edwardsiella ictaluri isolates in the channel and hybrid catfish and ornamental fish species. 45th annual meeting of Mississippi Chapter of the American Fisheries Society. Gulfport, MS.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Vandana Dharan, Nicholas Phelps, Lester Khoo, Ganesh Kumar, and Suja Aarattuthodi. 2020. Investigation of the epidemiology of Blue Catfish Alloherpesvirus (BCAHV). 45th annual meeting of Mississippi Chapter of the American Fisheries Society. Gulfport, MS.