2005 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Channel catfish aquaculture represents the largest venture of its kind in the U.S.; however, its viability is threatened by increasing disease losses. Commercial catfish production takes place in 13 states, but is concentrated in the Mid-South Area, particularly the Delta region of Northwest Mississippi. In 2003 the industry produced 300 million kilograms of foodsize fish, valued at approximately $400 million. However, the overall economic impact of U.S. catfish production vastly exceeds this figure. In Mississippi alone, the industry encompasses roughly 400 farms, 45,000 hectares of water and employs 7,000 workers. Mississippi accounts for approximately 60% of total foodsize fish production and is also the largest producer of fingerling “seed-stock.” When ancillary service industries are considered, the Mississippi industry contributes approximately $2 billion to the well being of this economically depressed region. Despite increased production, profitability of the catfish industry is declining. Since its inception more than 40 years ago, disease-related losses have represented a major impediment to economic performance. Losses from recognized infectious and environmental diseases have escalated as culture practices have become more intensive and there has also been an emergence of several previously unknown disease entities. It is estimated that disease-related mortalities account for approximately 45-50% of all losses incurred on farms and may account for as much as $100 million annually in direct economic impact. In the past 3 years, decreased production resulting from disease, in conjunction with historically low fish prices, competition with foreign imports, and rising feed costs has forced approximately 20% of farm acreage out of production. Without substantial improvements in fish health management and production efficiency, the future of commercial catfish farming will remain in jeopardy. This project addresses priority issues for increasing fish health, production efficiency and profitability of commercial catfish farming. The overall objective is to address current and emerging fish health problems by developing improved disease diagnostic methods and comprehensive management strategies. We have addressed these goals using a multidisciplinary approach that focuses on practical, production-oriented methods that integrate existing strengths of the National Warmwater Aquaculture Center with state-of-the-art technologies. This research directly addresses several components of the National Program 106 Aquaculture Action Plan, such as: Component 2 (Integrated Aquatic Animal Health Management) Problem a (Pathogen Identification and Disease Diagnosis), Problem b (Vaccines and Medicines), Problem c (Immunology and Disease Resistance), Problem e (Epidemiology), Problem g (Aquatic Animal Health Medicine), Problem h (Immune System Enhancement – Nutrients and Immunostimulants), as well as Component 4 (Growth and Development, and Nutrition). Taken as a whole, this project aims to develop an integrated system of managing catfish health problems and, therefore, all of the objectives ultimately address the primary stated goal of Problem g (Aquatic animal health medicine), which is to “improve health management practices currently used in aquaculture.” All objectives are focused on the area of fish health management and diagnostic medicine to establish new effective measures for the detection, prevention, and treatment of disease. Reducing disease-related costs will increase net profitability and help insure economic viability of the catfish industry. Advances in the understanding of disease transmission, pathogenesis, and epidemiology, along with the development of state-of-the-art diagnostic technologies, will provide benefits to the scientific community and fish health providers throughout the U.S. The program is closely integrated with the USDA-ARS, Catfish Genetics Research Unit and will enhance current projects involved in the genetic selection of disease-resistant lines of channel catfish. Expected products will ultimately be the development of best management practices (BMPs) that increase production efficiency, promote fish health, and reduce economic risks associated with disease losses. Ultimately, American consumers will be the major beneficiaries through the production of an inexpensive, safe, domestically produced seafood product that will help offset the large U.S. trade deficit in seafood commodities. 2.List the milestones (indicators of progress) from your Project Plan. Objective 1: Develop diagnostic tools to detect and monitor diseases in commercially raised channel catfish and determine virulence factors associated with those diseases. Hypothesis 1: A real-time PCR assay can be developed to study the epidemiology of proliferative gill disease. Milestones FY 2005 – Validate the specificity of a pair of H. ictaluri PCR primers and initiate the development of methodologies for isolating spores from pond water (filtration or imuno-capture). FY 2006 – Develop real-time PCR assay and optimize conditions for its use. FY 2007 and 2008 – Conduct field investigations using the PCR assay and optimize conditions for its use. FY 2009 – Objective complete. Hypothesis 2: A real-time immuno-PCR assay can be developed to study the epidemiology of enteric septicemia of catfish. Milestones FY 2005 – Optimize real-time PCR assay for E. ictaluri and develop immuno-capture methodologies. FY 2006 – Conduct laboratory trials and optimize conditions for use of assay. FY 2007 and 2008 – Conduct field trials and optimize conditions for use of assay. FY 2009 – Objective complete. Hypothesis 3: Early stages in the pathogenesis of enteric septicemia can be elucidated by examining differential protein expression by Edwardsiella ictaluri exposed to channel catfish intestinal mucus. Milestones FY 2005 – Evaluate growth of Edwardsiella ictaluri in water and catfish intestinal mucus. FY 2006 – Characterize protein expression under above growth conditions using electrophoresis. FY 2007 – Develop antibodies to proteins of interest identified above. FY 2008 – Evaluate protection derived from isolated proteins and conduct challenges. FY 2009 – Objective complete. Hypothesis 4: Strain differences in Edwardsiella ictaluri and Flavobacterium columnare can be identified by genetic variation among isolates. Milestones FY 2005 – N/A FY 2006 – Optimize ERIC, Rep, and BOX PCR methodologies for Edwardsiella ictaluri and Flavobacterium columnare. FY 2007 and 2008 – Analyze archived strains of above bacteria for genetic variation. FY 2009 – Conduct challenges. Hypothesis 5: Edwardsiella ictaluri strains isolated during epizootics at abnormally high water temperatures vary in growth and genetic features from those isolated at normal temperatures. Milestones FY 2005 – N/A FY 2006 – Optimize culture methods for growth of archived E. ictaluri strains growing at higher than expected temperatures. FY 2007 – Determine growth characteristics of above bacterial isolates and perform challenge trials on channel catfish fingerlings. FY 2008 – Objective complete. Objective 2: Develop fish health management procedures to control economically important diseases of channel catfish. Hypothesis 1: Acute and chronic Bolbophorus sp. trematode infections decrease growth, production efficiency, and health status of channel catfish fingerlings. Milestones FY 2005 – Evaluate effects of acute Bolbophorus sp. infections on channel catfish. FY 2006 and 2007 – Evaluate relationship of acute Bolbophorus sp. infection on susceptibility to enteric septicemia in pond studies. FY 2008 and 2009 – Evaluate the effects of chronic Bolbophorus sp. infection. Hypothesis 2: Method of vaccine preparation and bacterial exposure influence the efficacy of AQUAVAC-ESC® in challenge trials. Milestones FY 2005 – Optimize conditions for AQUAVAC-ESC® vaccination and conduct challenge trials. FY 2006 – Objective complete. Hypothesis 3: Feed restriction and inclusion of natural feeds to the diet enhance resistance to enteric septicemia of catfish and improves vaccine efficacy. Milestones FY 2005 – Establish validity of restricted feeding practices for control of enteric septicemia. FY 2006 and 2007 – Evaluate interaction of restricted feeding and AQUAVAC-ESC® vaccination on survival of channel catfish exposed to E. ictaluri infection. FY 2008 and 2009 – Conduct field trials. Hypothesis 4: AQUAVAC-ESC® and AQUAVAC-FC® used in combination will reduce losses of channel catfish fingerlings to enteric septicemia and columnaris disease. Milestones FY 2005 - Optimize conditions for AQUAVAC-FC® vaccination and conduct challenge trials. FY 2006 – Evaluate efficacy of combined AQUAVAC-ESC® and AQUAVAC-FC® vaccination on survival of channel catfish. FY 2007 – Continue to evaluate efficacy of combined AQUAVAC-ESC® and AQUAVAC-FC® vaccination on survival of channel catfish. FY 2008 and 2009 – Conduct field trials. Objective 3: Determine factors associated with emerging diseases in pond-raised channel catfish. Hypothesis 1: An unidentified toxin is responsible for visceral toxicosis of catfish (VTC). Milestones FY 2005 – Isolate and characterize toxin responsible for development of VTC. FY 2006 – Examine immune system recognition of VTC toxin and develop antibodies against the toxin. FY 2007 – Develop ELISA method for detection of VTC toxin. FY 2008 and 2009 – Conduct field trials. Hypothesis 2: Iron deficiency is responsible for development of channel catfish anemia (CCA). Milestones FY 2005 – Examine response of channel catfish suffering from natural development of CCA to parenteral iron and determine the lifespan of the catfish erythrocyte. FY 2006 – Evaluate effect of feeding an iron deficient diet on development of CCA-like disease. FY 2007 and 2008 - Examine possible mechanisms for the disturbance of normal iron metabolism in the pathogenesis of CCA. FY 2009 – Objective complete. Hypothesis 3: A new streptococcal disease causes losses of brood-sized channel catfish. Milestones FY 2005 – Characterize the streptococcal bacteria isolated from an emerging disease of channel catfish and fulfill Koch’s postulates. FY 2006 – Objective complete. Objective 4: Use epidemiological methods to investigate new and emerging diseases, and to identify environmental and management factors that influence the onset and severity of disease outbreaks. Hypothesis 1: A systematic data-collection system can be used to identify risk factors associated with the diseases visceral toxicosis of catfish and channel catfish anemia. Milestones FY 2005 – Develop infrastructure for data collection, including hiring of essential personnel and construction of database. FY 2006 – 2008 – Collect field data. FY 2009 – Evaluate associations from collected data. 4a.What was the single most significant accomplishment this past year? Enteric septicemia of catfish (ESC), caused by Edwardsiella ictaluri, is the most significant bacterial disease affecting the commercial production of channel catfish. Previous research has demonstrated that restriction of feed intake is as effective in curtailing mortalities from enteric septicemia as the everyday feeding of medicated feed containing the antibiotic Romet®. Although widely adopted by the industry, the validity of restricted feeding practices has recently been contradicted. Two studies were conducted to further evaluate survival in catfish fingerlings following variable periods of feed deprivation prior to and after exposure to E. ictaluri in controlled aquarium experiments. In both experiments, regardless of the pre-challenge feeding schedule, withholding feed from fish immediately following exposure to E. ictaluri significantly reduced mortalities. Pooled data revealed that withholding feed after bacterial challenge reduced mortalities by 52% in experiment 1 and 35-45% in experiment 2, compared to fish receiving feed daily. This relationship appears to be related to processes associated with the incidental ingestion of pathogenic bacteria present in water as fish congregate to feed. Restricted feeding schedules were shown to significantly reduce losses from ESC when implemented in the early stages of an epizootic and can be recommended as a preventive measure when fall temperatures become conducive to outbreaks of the disease. In addition to reducing mortalities, benefits to producers include decreased feed costs, improved water quality, and decreased reliance upon antibiotic medicated feeds. 4b.List other significant accomplishments, if any. In 2005, the Aquatic Diagnostic Laboratory processed approximately 1,800 case submissions, roughly half producer submitted clinical cases and half generated from research activities at the NWAC. In collaboration with USDA-ARS scientists, a substantial effort was directed toward the investigation of an unusual outbreak of channel catfish virus disease (CCVD) in USDA developed NWAC strain 103 catfish. Findings indicate an unusually virulent strain of virus and that the 103 strain is intermediate in susceptibility to CCVD. Other significant accomplishments during FY2005, include the development of a quantitative PCR assay to be applied to the study of proliferative gill disease in pond water. Similarly, an immuno-capture system has been tested to isolate E. ictaluri bacteria from pond water. The bacteria will then be enumerated in water samples using an existing quantitative PCR assay. Field and laboratory experiments have demonstrated the devastating effects of acute and chronic infections with Bolbophorus spp. trematodes and their potential economic impact on commercial catfish operations. Procedures for the preparation of AQUAVAC-ESC have been enhanced through the determination of optimal salt concentrations to be used in the vaccine bath solution. The addition of zooplankton to the diets of fry has been shown to improve growth and increase resistance to ESC in a continuous challenge model. A possible cause for visceral toxicosis of catfish has been found using neutralization studies and the role of iron deficiency in the development of channel catfish anemia has been demonstrated. Lastly, a previously unknown streptococcal disease of channel catfish broodstock has been described and a new species of bacteria isolated. 4c.List any significant activities that support special target populations. It is estimated that disease-related mortalities account for 45-50% of all losses incurred on farms and may account for as much as $100 million annually in direct economic impact. To maintain profitability in the face of depressed farm prices, rising feed costs, and competition with foreign imports, it is essential to curtail monetary losses resulting from disease. The Mississippi Agricultural and Forestry Experiment Station and College of Veterinary Medicine’s Aquatic Diagnostic Laboratory provide an ongoing critical service to the commercial catfish industry in the form of disease diagnostics and surveillance, detection of new and emerging diseases, field disease investigation, and applied research designed to increase production efficiency through improved fish health. Information transfer occurs through on-farm visits, telephone and laboratory consultations, demonstration projects, and producer workshops conducted at the NWAC and elsewhere. 4d.Progress report. In 2005, significant progress was made toward the completion of milestones established in the current project plan approved by OSQR review one year ago. A pair of PCR primers for H. ictaluri, the cause of proliferative gill disease, was developed and their specificity against related myxozoans found in catfish ponds validated. Furthermore, the primers have been adapted to real-time PCR methodologies for the enumeration of spores in present in water. Filtration methods for the isolation of H. ictaluri spores have been abandoned due to interference by heavy algal densities in pond water. As an alternative, spores have been collected from D. digitata worms shedding the organism and forwarded to a commercial laboratory for the production of an antibody to be used in an immuno-capture system. In the interim, a density gradient system is being tested for the isolation of spores. Magnetic beads coated with an Edwardsiella ictaluri, the cause of enteric septicemia of catfish (ESC), specific antibody have been used to capture the bacteria in filter sterilized pond water and compared to numbers in broth cultures. At bacterial concentrations of 104 CFU/ml or less, the protocol allows the detection of greater than 95% of the bacteria present. Ongoing experiments are being conducted to determine the efficiency of the protocol in capturing E. ictaluri from unfiltered pond water to which known numbers of bacteria have been added. Once this is determined, the protocol will be used in conjunction with an already developed highly sensitive real-time PCR protocol to enumerate bacterial numbers in pond water samples, providing an invaluable research tool for the study of ESC in the environment. In additional studies with ESC, experiments have determined that E. ictaluri decreases in concentration approximately one order of magnitude in filter sterilized pond when compared to bacteria maintained in broth culture over a 7-day period. Samples of bacteria have been collected at 0, 4, 24, 48, and 168 hours for electrophoretic comparison of differences in protein expression. Further experiments have been initiated to determine how the addition of intestinal mucus to the pond water influences growth and protein expression of the organism. Comparison of protein expression under the different growth conditions will be used to determine mechanisms used by E. ictaluri for survival in the environment and in invasion of the intestinal lining of fish. Monitoring and surveillance studies have demonstrated that Bolbophorus spp. trematode infections, have become a widespread problem on commercial operations in Northwestern Mississippi. Farms with heavy infestations were shown to be in close proximity to white pelican roosting and resting sites. Field and diagnostic observations indicate that infested populations of fish have an increased incidence of other infectious diseases, such as ESC. Furthermore, analysis of production records from commercial facilities demonstrated a 27-32% reduction in total feed consumption in infested populations of fish. Economic analysis revealed that fish growth and survival in affected populations of fish was unable to cover the variable costs of production inputs. Experimental pond studies demonstrated similar results where mild trematode infestations reduced total feed consumption and production efficiency. In laboratory studies, acute Bolbophorus spp. infections were shown to significantly increase mortalities associated with E. ictaluri infection by approximately 50%. AQUAVAC-ESC is a commercially available live attenuated vaccine developed for use against enteric septicemia of catfish (ESC). The vaccine is delivered as a bath by reconstituting a lyophilized vaccine culture with water and adding the contents to 3.78 L of hatchery water, to deliver a target dose of 1x107 CFU/ml. Laboratory and clinical trials demonstrated inconsistencies in viable cell counts during preparation of the vaccine bath. Varying concentrations of salts (NaCl, CaCl2, and Aquahaul®) were mixed with the bath water before adding the reconstituted vaccine culture. Results demonstrated an increase in viable cell counts with increasing osmotic concentrations in the vaccine bath. To ensure an adequate concentration of viable cells, it is recommended that 3 to 6 g/L of salt (NaCl or Aquahaul®) be added to the bath water before the addition of the reconstituted vaccine culture. To better assess the efficacy of AQUAVAC-ESC and the resistance of catfish to enteric septicemia, experiments were conducted to develop laboratory protocols that better reflect the natural mode of E. ictaluri infection. Challenge models were developed to continually expose fish to low dosages of virulent bacteria by pumping a reservoir inoculum through test aquaria. Challenge trials demonstrate that manipulating the method of exposing fish to infectious doses of E. ictaluri can influence the outcome of disease challenge trials. In a series of laboratory trials, brief periods of feed deprivation following exposure to E. ictaluri were shown to significantly reduce deaths associated with enteric septicemia of catfish. A causal effect cannot be firmly concluded, but this relationship appears to be related to processes associated with the incidental ingestion of pathogenic bacteria present in water as fish congregate to feed. Restricted feeding schedules can significantly reduce losses from ESC on commercial production facilities if implemented in the early stages of epizootics, or can be employed as a preventive measure when fall temperatures become conducive to outbreaks of the disease. To increase growth and performance of channel catfish fry, commercial fry diets were supplemented with dried and live zooplankton. Supplemented diets were shown to increase growth by approximately 25% at 7 and 14 days post swim-up. Using the continuous dose challenge model, developed in Objective 2, Hypothesis 2 of the project plan, the resistance of fish fed the two diet regimens were evaluated and compared to results obtained from standard single high-dose challenge models. No differences in survival were observed between fish fed the supplemented and non-supplemented diets using the single high-dose challenge model. In contrast, fry fed commercial diets supplemented with live or dried zooplankton were significantly more resistant to E. ictaluri infection compared to fry fed the non-supplemented diets. These data indicate the method of infecting fish can influence the outcome of disease challenge trials and that the continuous challenge method may be a more accurate method of assessing disease resistance and vaccine efficacy, as it more closely mimics conditions in the pond environment. AQUAVAC-Columnaris is a live attenuated vaccine developed for use against columnaris disease. The vaccine is delivered as a bath by rehydrating the lyophilized vaccine culture with water and adding the contents to 3.78 L of hatchery water to deliver a target dose of 1x107 CFU/ml. The effect of osmolality on viable cells counts in the vaccine bath solution was evaluated, however, unlike the studies described above involving AQUAVAC-ESC, osmotic gradients were not shown to effect viable cell counts. In conjunction with bioassay testing procedures developed at the NWAC for the diagnosis of visceral toxicosis of catfish (VTC), neutralization studies have protected experimental fish from the unknown toxic component present in the serum of affected catfish. These studies provide for the first time strong circumstantial evidence for a possible cause of VTC. As additional field cases are diagnosed, confirmatory studies will be conducted. Analysis of blood and tissue samples collected from catfish suffering from natural outbreaks of channel catfish anemia demonstrated significantly lower levels of circulating (serum) and stored (liver) iron in affected fish. In laboratory trials, following the parenteral administration of iron dextran, hematocrits began to increase in a little as 14 days and full recovery was seen by 45 days. Human recombinant erythropoietic had no demonstrable effect in affected or control fish. These findings suggest that iron deficiency may be responsible for this enigmatic disease. Attempts to determine the erythrocyte lifespan using a biotin-streptavidin detection system produced inconclusive results in laboratory aquarium studies, possibly due to the sequestration of labeled erythrocytes in the spleen. The study is being repeated under conditions more representative of the natural pond environment. Findings from these studies have promoted a collaborative effort with researchers at Auburn University to investigate the pathogenesis of the disease. Gross and histopathological descriptions of a previously unknown streptococcal disease in channel catfish broodstock are complete. On commercial operations the infection has resulted in chronic low-grade mortalities and poor reproductive success. The bacteria produce skin ulcers and appear to have a tropism for bone and joints. Similar lesions have been experimentally reproduced and the bacteria recovered, fulfilling Koch’s postulates. Characterization of the bacteria itself has been completed to the fullest capabilities of this laboratory, including amplification and analysis of 16S rDNA gene sequences. We are now working in collaboration with Dr. Patricia Shewmaker at the Center’s for Disease Control (CDC) to complete full genetic characterization of the organism. All work conducted at the NWAC and at the CDC indicate this is a new bacterial species. A computerized database has been constructed to collect information on feed consumption, stocking rates, harvest rates, mortality rates, water quality, and disease diagnoses. This project is being conducted in collaboration with a large commercial catfish producer and represents a major step forward in cooperation with the catfish industry. Four years of data will be collected and the information gained will be used to examine interactions between disease incidence, production parameters, and the environment. 5.Describe the major accomplishments over the life of the project, including their predicted or actual impact. The catfish health research project was initiated on 08/01/02 to develop a comprehensive disease management program that addresses disease related problems that threaten the economic wellbeing of commercial channel catfish farming. The current project plan, approved in 2004, continues to enhance existing disease research and diagnostic programs at the Thad Cochran National Warmwater Aquaculture Center. Major accomplishments to date involve investigation of the prevalence, severity, and economic impact of Bolbophorus sp. trematode infections, as well as the development of practical management strategies. Other accomplishments include the determination of a link between iron deficiency and channel catfish anemia, identification of a new streptococcal disease of catfish, elucidation of a possible cause for visceral toxicosis, the development of management strategies for proliferative gill disease, and the development of restricted feeding practices to control enteric septicemia. Accomplishments expected over the life of the project are to:. 1)Develop state-of-the-art diagnostic tools and procedures to detect and monitor diseases in commercially raised channel catfish;. 2)Develop best management practices for improving fish health and increasing the profitability of catfish farming by limiting the economic impact of infectious and non-infectious diseases;. 3)Develop field and laboratory disease challenge models used to study pathogenic mechanisms of disease and develop effective control strategies;. 4)Maintain a field service program to investigate new and emerging diseases, identify environmental and management factors that influence the onset and severity of disease outbreaks; and. 5)Establish the epidemiology of economically significant diseases, particularly those of unknown origin. 6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Activities of the Aquatic Diagnostic Laboratory, including case summaries and disease trends are and made available to producers, university and government officials in the form of an annual report. Research activities are described in a variety of formats, including publications of the Southern Regional Aquaculture Center, National Warmwater Aquaculture Center, a producer’s trade journal, and in scientific journals. Verbal transfer of information occurs through phone and laboratory consultations, and through various workshops, demonstration projects, on-farm visits, and at scientific meetings. More specifically, in 2005 work on the control of Bolbophorus spp. trematodes was presented at producer workshops and at the 30th Eastern Fish Health Workshop. Findings on the description and characterization of a new streptococcal disease of catfish were presented at the American Fisheries Society, Fish Health Section Annual Meeting. Studies on the use of the antibiotic florfenicol were presented at the United States Fish and Wildlife Service 10th Annual Investigational New Animal Drug Workshop. Information on disease incidence, Bolbophorus spp. trematodes, and streptococcosis appeared in the NWAC newsletter. Findings on the investigation of an unusual outbreak of channel catfish virus in USDA developed NWAC 103 strain catfish appeared in the Catfish Journal. The results of scientific investigations on a variety of fish health issues appeared in ten abstracts published through the World Aquaculture Society, Aquaculture America, American Fisheries Society, and Eastern Fish Health Workshop. Two scientific articles appeared in the Journal of Aquatic Animal Health. 7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Popular Articles: Camus, A., Gaunt, P., Mauel, M. 2005. 2004 CVM Aquatic Diagnostic Laboratory summary. NWAC News 8(1):6-7. Camus, A., Wise, D. 2005. Streptococosis, a previously unknown disease of channel catfish broodstock. NWAC News 8(1):8. Wise, D., Mischke, C., Byars, T. 2005. Use of elevated levels of copper sulfate to eliminate snails. NWAC News 8(1):1-2. Tucker, C., Silverstein, P., Camus, A., Bilodeau, L., Wise, D., Waldbeiser, G. 2005. Channel catfish virus and NWAC103 catfish. The Catfish Journal. January 2005:8. Presentations: Gaunt, P. 2004. Overview of florfeniol (Aquaflor®) research in channel catfish: efficacy, safety, residue depletion studies, and application to the catfish industry. NWAC Fall Seminar 2004. Stoneville, MS. Gaunt, P. 2004. Overview of florfeniol (Aquaflor®) research in channel catfish: efficacy, safety, residue depletion studies, and application to the catfish industry. NWAC Fall Seminar 2004. Starkville, MS. Gaikowski, M.P., Darwish, A., Gaunt, P., Rach, J. 2004. A review of fish disease model development. United States Fish and Wildlife Service 10th Annual Investigational New Animal Drug Workshop. Bozeman, MT. Gaunt, P., McGinnis, A., Baumgartner, W., Camus, A., Cao, J., Endris, R. 2004. Efficacy of florfenicol (Aquaflor®) in tilapia (Oreochromis niloticus) with Streptococcus iniae infection. United States Fish and Wildlife Service 10th Annual Investigational New Animal Drug Workshop. Bozeman, MT. Gaunt, P., Camus, A., McGinnis, A., Simmons, R., Endris, R. 2004. Efficacy of florfenicol for control of mortality caused by Streptococcus iniae in tilapia. World Aquaculture Society. Honolulu, Hawaii. Mischke, C.C., Wise, D.J., Li, M.H., Zimba, P.V. 2005. Recent developments in channel catfish Ictalurus punctatus fry culture: the role of natural food. Aquaculture America 2005. New Orleans, LA. Wise, D.J., Camus, A.C. 2005. Control of bacterial infections in channel catfish, Ictalurus punctatus, fingerlings using medicated feeds and restricted feeding practices. Aquaculture America 2005. New Orleans, LA. Steeby, J., Wise, D.J., Thompson, L. 2005. Use of smallmouth buffalo Ictiobus bubalus in commercial catfish ponds to reduce the incidence of proliferative gill disease. Aquaculture America 2005. New Orleans, LA. Gaunt, P., McGinnis, A., Baumgartner, W., Camus, A., Cao, J., Endris, R. 2005. Assessment of florfenicol (Aquaflor®) against Streptococcus iniae in vitro and in vivo in nile tilapia (Oreochromis niloticus). Aquaculture America 2005. New Orleans, LA. Wise, D., Mischke, C., Byars, T., Camus, A. 2005. Evaluation of copper sulfate to control snail numbers in catfish ponds affected by Bolbophorus trematodes. 30th Eastern Fish Health Workshop, Shepherdstown, WV. Pote, L.M., Yost, M.C., Doffitt, C.M., Dorr, B.S., King, D.T., Camus, A., Wise, D. 2005. Further elucidation of the life cycle and pathology of the digenetic trematode, Bolbophorus damnificus. 30th Eastern Fish Health Workshop, Shepherdstown, WV. Camus, A., Wise, D., Mauel M., Shewmaker, P. 2005. Streptococcal arthritis, osteolysis, myositis, and spinal meningitis in channel catfish Ictalurus punctatus broodstock. American Fisheries Society, Fish Health Section. Minneapolis, MN.