Progress 12/18/03 to 11/11/04
Outputs
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? Aquaculture has been a rapidly growing source of food production over the last few decades; total production value in the United States for 2000 was $973 million, of which total finfish production was $714 million. Fish pathogens continue to inflict significant economic losses to the U.S. aquaculture industry; extension personnel estimate that 10% of production ($71.4 million) is lost to parasites and infectious diseases. Current knowledge is inadequate for devising comprehensive management strategies for disease control. Many of the infectious diseases in fish (bacterial, fungal, and parasitic) do not have effective vaccines; therefore, the need for safe and effective control measures to minimize losses due to outbreaks is pressing and critical. Available Food and Drug Administration-approved
therapeutants are very limited, and the industry is frequently faced with disease epizootics and no effective measures to curb losses. There is currently one parasiticide and three antibiotics (one is no longer manufactured) approved for use in U.S. aquaculture, with each therapeutant having a specific use. This is an inadequate arsenal against the plethora of diseases inflicting losses to the aquaculture industry. Approval of therapeutic compounds requires comprehensive studies to demonstrate human food safety, animal safety, environmental safety, and efficacy. The development of effective strategies to control fish health problems is also hampered by the limited understanding of the biology, vectors, and epidemiology of fish pathogens plaguing the aquaculture industry. The need for disease control methods (chemical, biological, or environmental) not targeted at the pathogen, but at the intermediate host of these pathogens, is also immediate and critical. The project has two
specific goals: 1) develop data needed to demonstrate safety (animal, human, and environmental) and efficacy of compounds that are relevant to the needs of aquaculture, 2) determine the efficacy of compounds, biological control strategies, clearance rate and pathogenesis (understanding of the disease process) of parasites and fungi applicable to catfish, baitfish, and Morone sp. culture. The research to be undertaken falls within the Integrated Aquatic Animal Health Management component of NP-106 - Aquaculture. The project focuses primarily on the problems addressed in 'Vaccines and Medicines' goals to 'Develop safe and effective vaccines and medicines for prevention and control of economically important pathogens of aquatic animals' and to 'Conduct research and development to support approval and licensing of safe and effective new drugs, vaccines and other biologics for aquaculture'. The project includes elements of the problems addressed in 'Mechanism of Disease' goals to 'Develop
challenge models in the laboratory that reflect on farm conditions to assess pathogenesis of disease' and to 'Develop basic information on the sources of infection, modes of transmission, routes of entry, virulence mechanisms and host response to economically important infectious and non-infectious diseases'. Attaining these objectives will provide benefits to farmers, fish health providers, scientists, and the public, which will result in increased economic growth by helping to overcome the impact of disease. Environmentally friendly, effective, and food-safe medicines to treat aquatic animal diseases and non-chemical methods to control diseases and disease vectors will become available not only to large commercial producers, but also to small, rural fish farmers. Research will provide the U.S. fish industry with the ability to identify important fish- pathogen hosts so the workforce can limit access of these hosts to ponds. Anticipated products of the research will be additional
fish health management strategies for fish diseases (bacteria and parasites) including FDA-approved compounds and the development of chemical and biological control methods to eliminate or reduce populations of non-fish hosts. Fish farmers of cultured hybrid striped bass, catfish, tilapia, and baitfish species will benefit from this research. Scientists will benefit from the basic knowledge of efficacy and safety of fisheries chemicals used for therapy and vector reduction and the use of biological controls. Fisheries extension agents and veterinarians will have more disease control methodologies available for recommendation to their user groups. Consumers demanding safe and wholesome fish products will benefit. 2. List the milestones (indicators of progress) from your Project Plan. This is a bridging project, and has not undergone peer review. A new project plan entitled "Evaluation of Compounds and Strategies for Controlling Aquatic Animal Disease" has been submitted to the
Office of Scientific Quality Review for peer review of technical quality and relevance to National Program 106 - Aquaculture. The following project milestones include the bridging project and those anticipated as being included in the new project: Bridging Project: (FY 2004) The efficacy of amoxicillin for controlling an experimental Streptococcus iniae infection in tilapia will be determined. The genotypes of Flavobacterium columnare strains isolated from field outbreaks in the U.S. will be characterized. This study will provide crucial epidemiological data to control infection in the aquaculture industry. The field efficacy of potassium permanganate for control of ichthyophthiriasis in channel catfish will be determined. A comparison of the pond shoreline treatments of hydrated lime and copper sulfate in experimental ponds will be made. Trematodes that infect cultured fish but that are collected from aquatic birds, other fish, and snails will be processed for identification, and
carrier hosts of specific trematodes will be determined. A treatment for the Asian tapeworm that infects the intestines of fish will be screened and tested for efficacy. Anticipated Milestones From New Project Currently Under Peer Review: Year 1 (FY2005) Establish in vitro sensitivity of F. columnare to florfenicol. Establish safety of copper sulfate to channel catfish. Optimize hydrated lime shoreline treatment for snail control. Determine praziquantel toxicity to grass carp. Year 2 (FY2006) Establish infection model of external columnaris in channel catfish. Establish efficacy of potassium permanganate against external columnaris in channel catfish. Determine praziquantel toxicity to golden shiners. Compare shoreline treatments for snail control. Year 3 (FY2007) Gain FDA approval of copper sulfate for controlling Ich in channel catfish in earthen ponds. Establish efficacy of florfenicol against Streptococcus iniae in hybrid striped bass. Determine consumption of snails by sunfish.
Determine final hosts of specific trematodes. Establish efficacy of DiquatRG and copper sulfate for channel catfish eggs infected with fungus. Year 4 (FY2008) Establish efficacy of DiquatRG against external columnaris in channel catfish. Establish safety of potassium permanganate to channel catfish. Establish efficacy of florfenicol against columnaris in channel catfish. Complete shoreline treatment field tests to control snails. Establish efficacy of praziquantel against Asian tapeworm in golden shiners or grass carp. Establish efficacy of diflubenzuron against anchor parasite in goldfish. Establish efficacy of hydrogen peroxide and formalin for channel catfish eggs infected with fungus. Year 5 (FY2009) Gain FDA-approval of potassium permanganate for external columnaris. Establish safety of florfenicol on hybrid striped bass. Determine snail consumption by other species. Determine longevity of trematode in catfish. Determine Diflubenzuron treatment for fish lice. Compare all treatments
to control egg fungi in channel catfish. 3. Milestones: A. List the milestones that were scheduled to be address in FY2004. The milestones listed below were scheduled to be completed under the bridging project in FY 2004. All milestones were completed, except for the field efficacy study of potassium permanganate. Several trials of this study indicated that there is a low margin of safety between efficacy and toxicity for potassium permanganate. Therefore, efficacy of potassium permanganate on other pathogens will be pursued. An experimental efficacy trial of amoxicillin for controlling S. iniae in tilapia has been conducted. This milestone has been completed. The genotypes of the F. columnare strains isolated from field outbreaks in the U.S. have been characterized using the 16S rRNA gene. This study will provide crucial epidemiological data to control infection in the aquaculture industry. This milestone has been completed. A comparison of the pond shoreline treatments of
hydrated lime and copper sulfate in experimental ponds was made. This milestone has been completed. Trematodes that infect cultured fish but that are collected from aquatic birds, other fish and snails were processed for identification, and carrier hosts of specific trematodes will be determined. This milestone has been completed for aquatic birds. A treatment for the Asian tapeworm that infects the intestines of fish was screened and tested for efficacy. This milestone has been completed B. List the milestones that you expect to address over the next 3 years. What do you expect to accomplish, year by year, over the next 3 years under each milestone? The Year 1, 2 and 3 milestones for the replacement project are listed below with a description of the anticipated outcomes. The entire project is currently undergoing OSQR review and is scheduled to be implemented beginning FY 2005. Year 1 (FY2005) Establish in vitro sensitivity of F. columnare to florfenicol. Knowing the in vitro
sensitivity will allow the researcher to identify the potential effectiveness of florfenicol against various strains of F. columnare. Establish safety of copper sulfate to channel catfish. This data is required by the FDA and will allow the compound to be safely used as a therapeutant in catfish production. Optimize hydrated lime shoreline treatment for snail control. This compound can be used as an alternative snail control when the use of copper sulfate is not appropriate. Determine praziquantel toxicity to grass carp. These results will allow an effective Asian tapeworm treatment to be used safely on grass carp. Year 2 (FY2006) Establish infection model of external columnaris in channel catfish. This will allow laboratory efficacy trials to be replicated as needed for FDA studies. Establish efficacy of potassium permanganate on external columnaris in channel catfish. This data is required by the FDA for future drug approval and will allow the compound to be effectively used as
a therapeutant in catfish production. Determine praziquantel toxicity to golden shiners. These results will allow an effective Asian tapeworm treatment to be used safely on baitfish. Compare shoreline treatments for snail control. These comparative studies will determine differences in treatment effectiveness between hydrated lime and copper sulfate under identical environments. Year 3 (FY2007) Gain FDA-approval of copper sulfate for controlling Ich in channel catfish in earthen ponds. This research effort will generate the only economical and approved parasiticide for fisheries use. Establish efficacy of florfenicol on Streptococcus iniae in hybrid striped bass. This data is required by the FDA for future drug approval and will allow the compound to be effectively used as a therapeutant in hybrid striped bass production. Determine consumption of snails by sunfish. This research will provide information for non-chemical control of aquatic snails. Determine final hosts of specific
trematodes. These results will lead to effective control of trematode infections in aquaculture and may identify new vectors. Establish efficacy of DiquatRG and copper sulfate for channel catfish eggs infected with fungus. This data is required by the FDA for future drug approval and will allow the compound to be effectively used as a therapeutant in catfish production. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY2004. A 1364-page proprietary target animal safety final study report for use of copper sulfate on channel catfish (for control of Ich) was prepared for the copper sulfate sponsor company, who submitted the report to the Food and Drug Administration/Center for Veterinary Medicine (FDA/CVM). This final study report, when approved, will complete the animal safety technical section for the future approval of copper sulfate as a therapeutant in aquaculture. This study was completed on-site and under GLP
guidelines (Good Laboratory Practices) determined the safety of copper sulfate to channel catfish at one, three, and five times the recommended therapeutic dose when treated daily for 11 days. Results indicate there was no mortality or histological changes due to copper toxicity at five times the therapeutic dose; this report is presently under review by FDA/CVM. The impact of this accomplishment could be to have a much-needed parasiticide as an FDA-approved aquaculture therapeutant upon completion of the single remaining technical section. B. Other significant accomplishment. Streptococcal infections can cause devastating mortalities in hybrid striped bass production. The efficacy of amoxicillin for controlling Streptococcus iniae infection in tilapia was demonstrated using a laboratory disease model developed in our laboratory. This data could support the future approval of amoxicillin as an antibiotic to treat S. iniae infection in tilapia, which can be a devastating disease in
the industry. Trials were run to show that amoxicillin is effective in decreasing the mortalities in infected fish from 96% to 6%. The immediate impact of this accomplishment has been for the FDA to allow the continued temporary use of this compound for disease control; amoxicillin is a proven effective and economical control for S. iniae in hybrid striped bass facilities. Ammonia buildup in shipping and other small containers for fish can result in stressed or even dead fish. Industry suppliers give little to no information on the quality of their zeolite products; therefore a simple method to evaluate zeolites of unknown quality was developed. Fish producers or extension agents can use this method to evaluate zeolites and select the best performing. As a result fish in small containers can be kept in the best possible condition because they were subjected to the least amount of stress from ammonia buildup. C. Significant activities that support special target populations.
Accomplishments directly support economic development of people in the Mississippi Delta, a special target population. The economic value of fish production greatly benefits the rural areas of the Delta regions of the southeastern U.S. that are characterized by high unemployment, low income and economic stagnation. Commercial fish farming has a significant impact on the economy of the Delta region of the U.S. and has a potential for growth that far exceeds its present economic importance. While fish farming provides jobs to farm workers, its major impact to rural populations is jobs creation in numerous collateral industries such as aquaculture equipment manufacturing, feed mill operations, processing, and transportation. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. This is a bridging project that supersedes the previous project "Research Evaluation for Registration of Chemicals and Approvals of New Animal Drugs for
Aquaculture" CRIS # 6225-32000-001-00D which was established in FY 1999. There are several major accomplishments from the previous project. 1) The efficacy for amoxicillin in hybrid striped bass and tilapia was established. 2) An effective oxytetracycline treatment to control streptococcal infections in tilapia was determined using a disease model developed in our laboratory. 3) The anti-helminthic drug Praziquantel was shown to be an effective control agent against the yellow grub in hybrid striped bass and the Asian tapeworm in grass carp. 4) A laboratory model was developed that permits efficacy testing of therapeutants for controlling Ichthyophthiriasis. 5) The treatment regime of a combination of copper sulfate and citric acid as a shoreline treatment to control disease transmitting snails was developed and has been registered for use by EPA. 6) The efficacy of copper sulfate and potassium permanganate in preventing establishment of Ichthyophthiriasis and in eliminating
existing infestations in channel catfish was determined. 7) Reports have been prepared and submitted to FDA/CVM for target animal safety, efficacy, human food safety, and environmental safety for future approval of copper sulfate as a therapeutant in aquaculture (the efficacy and human food safety technical sections have been approved). 8) Reports have been prepared and submitted to FDA/CVM for efficacy, and human food safety for future approval of potassium permanganate as a therapeutant in aquaculture (the human food safety technical section has been approved). 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? Results of research studies and technologies developed were made available to customers and the general public through oral presentations
(technical and non-technical), poster presentations at local, state, national and international meetings, and scientific publications. Research findings were presented at the international Aquaculture 2004 conference in Honolulu, HI, at the 28th Annual Eastern Fish Health Workshop, Atlantic Beach, NC, the Southern Conference of Researchers in Aquatic Diseases annual meeting, Biloxi, MS, and at the 2004 AFS Fish Health Section meeting, Kearneysville, WV, and at the Arkansas Aquaculture meeting, Hot Springs, AR. Information on efficacy, target animal safety studies and environmental assessments were presented to FDA representatives at Joint Subcommittee on Aquaculture - Quality Assurance meeting, Washington, D.C. A special session entitled 'Therapeutic Drug Research' was again organized in conjunction with the U.S. Fish and Wildlife Service at the World Aquaculture Society annual meeting. This session will be held annually and was sorely needed for researchers in this specialty area
to communicate ideas with their peers. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Popular Press: Straus, D.L. October 2003. Use of copper sulfate to prevent mortality from ich in channel catfish ponds. The Catfish Channel Newsletter of Catfish Farmers of Arkansas v. 43. p. 4. Mitchell, A.J., Wise, D. 2004. The latest on pond shoreline treatments for snails. The Catfish Journal. v. 18(7). p. 21-22.
Impacts
(N/A)
Publications
- Green, C.C., Lochmann, S.E., Straus, D.L. 2004. Acute toxicity of isopropyl methylphosphonic acid, a breakdown product of sarin, to eggs of golden shiner and channel catfish [abstract]. 48th Annual Rural Life Conference Book of Abstracts. p. 19.
- Darwish, A.M., Ismaiel, A.A. 2003. Laboratory efficacy of amoxicillin for the control of streptococcus iniae infection in hybrid striped (sunshine) bass. Journal of Aquatic Animal Health. 15:209-214.
- Mitchell, A.J., Hobbs, M.S. 2003. Effect of citric acid, copper sulfate concentration, and temperature on a pond shoreline treatment for control of the rams-horn snail planorbella trivolvus and the potential toxicity of the treatment to channel catfish. North American Journal of Aquaculture. 65:306-313.
- Mitchell, A.J., Oats, D.W. 2004. Nodular masses in the swimbladder and visceral fat of the walleye stizostedion vitreum. Nebraska Academy of Science. 29:25-27.
- Straus, D.L. 2004. Comparison of the acute toxicity of potassium permanganate to hybrid striped bass in well water and diluted well water. Journal of the World Aquaculture Society. 35(1):55-60.
- Darwish, A.M. 2004. Laboratory efficacy of amoxicillin for control of strepococcus iniae infection in hybrid striped (sunshine) bass [abstract]. In: Aquaculture America Conference. p. 146.
- Mitchell, A.J., Snyder, S.G. 2004. Side-by-side comparisons of the effectiveness of copper sulfate and slurried hydrated lime pond shoreline treatments against the rams-horn snail [abstract]. Book of Abstracts World Aquaculture Society. p. 406.
- Mitchell, A.J. 2004. A simple assay to compare zeolites of unknown quality [abstract]. Book of Abstracts World Aquaculture Society. p. 405.
- Cartwright, D.O., Blazer, V.S., Sehill, W.B., Beauchamp, K.A., Mitchell, A. J. 2004. Preliminary study on the mitochondrial genome of the tapeworm bothriocephalus acheilognathi [abstract]. In: Annual Eastern Fish Health Workshop. p. 59.
- Mitchell, A.J. 2004. Praziquantel bath treatments against the asian tapeworm in grass carp [abstract]. In: Southern Conference of Researchers in Aquatic Diseases. p. 25.
- Mitchell, A.J. 2004. Reasons for the occurrences of massive trematode infestations in cultured fish [abstract]. In: Annual Eastern Fish Health Workshop. p. 32.
- Straus, D.L. 2003. Toxicity of potassium permanganate to hybrid striped bass in well water [abstract]. Society of Environmental Toxicology and Chemistry Abstracts. p. 161.
- Green, C.C., Lochmann, S.E., Straus, D.L. 2003. Toxicity of isopropyl methylphosphonic acid to eggs of golden shiner and channel catfish [abstract]. Society of Environmental Toxicology and Chemistry Abstracts. p. 172.
- Green, C.C., Lochmann, S.E., Straus, D.L. 2003. Toxicity of isopropyl methylphosphonic acid to eggs of golden shiner and channel catfish. [abstract] Journal of Society of Environmental Toxicology and Chemistry. p. 11.
- Straus, D.L. 2004. Efficacy of copper sulfate in preventing mortality due to ichthyophthiriasis in channel catfish - a simulated field study [abstract]. Book of Abstracts World Aquaculture Society. p. 563.
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