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United States Department of Agriculture

Agricultural Research Service

Research Project: EVALUATION OF COMPOUNDS AND STRATEGIES FOR CONTROLLING AQUATIC ANIMAL DISEASE

Location: Harry K. Dupree Stuttgart National Aquaculture Research Center

2006 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? Why 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; the industry is frequently challenged 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 hybrid striped bass 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 by year the currently approved milestones (indicators of research progress)
YEAR 1 (FY2005) Establish safety of copper sulfate to channel catfish.

Optimize hydrated lime shoreline treatment for snail control.

YEAR 2 (FY2006) Establish infection model of external columnaris in channel catfish.

Determine praziquantel toxicity to grass carp.

Determine praziquantel toxicity to golden shiners.

Compare shoreline treatments for snail control.

Establish efficacy of florfenicol against Streptococcus iniae in hybrid striped bass.

YEAR 3 (FY2007) Gain FDA-approval of copper sulfate for controlling Ich in channel catfish in earthen ponds.

Establish in vitro sensitivity of Flavobacterium columnare to florfenicol.

Establish efficacy of potassium permanganate against external columnaris in channel catfish.

Determine consumption of snails by sunfish.

Determine final hosts of specific trematodes.

Establish efficacy of Diquat® and copper sulfate for channel catfish eggs infected with fungus.

YEAR 4 (FY2008) Establish efficacy of Diquat® 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.


4a.List the single most significant research accomplishment during FY 2006.
EFFICACY OF FLORFENICOL AGAINST STREPTOCOCCUS INIAE INFECTION IN HYBRID STRIPED BASS DEMONSTRATED: The survival of the hybrid striped bass industry in the US is closely linked to the ability to control this bacterial infection. Scientists at the HKD Stuttgart National Aquaculture Research Center demonstrated that florfenicol increased the survival of infected fish from 4% to 94%. This accomplishment provides critical data to support the future FDA-approval of florfenicol against this bacterial infection in hybrid striped bass. This accomplishment can be linked to a Year 2 (FY2006) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2 - Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.


4b.List other significant research accomplishment(s), if any.
DETERMINED DOSE OF COPPER SULFATE TO CONTROL FUNGUS ON CHANNEL CATFISH EGGS: This research addresses egg mortality from fungus in catfish hatcheries. A range-finding study by scientists at the HKD Stuttgart National Aquaculture Research Center determined that treating catfish eggs daily with 10 ppm copper sulfate until eyes develop will prevent fungus from growing and destroying the eggs in high alkalinity/moderate hardness water at 74 degrees F. This accomplishment will provide direct benefits through increased survival rates in catfish hatcheries and will economically benefit the industry; this research is also required by FDA for a future label claim. This accomplishment can be linked to a Year 3 (FY2007) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2 - Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

EFFECTIVENESS OF SOLID AND LIQUID FORMULATIONS OF COPPER SULFATE FOR CONTROLLING ICHTHYOPHTHIRIASIS DETERMINED: This research addresses claims that commercial liquid copper formulations are more effective at controlling Ichthyophthiriasis caused by Ichthyophthirius multifiliis (Ich) than copper sulfate. The acute toxicity of copper sulfate crystals and a liquid copper sulfate formulation to channel catfish and free-swimming Ich was determined in low and high alkalinity waters by scientists at the HKD Stuttgart National Aquaculture Research Center in cooperative studies with the University of Arkansas at Pine Bluff, Pine Bluff, AR. The impact of this accomplishment will be directly seen as fish-farmers can use much cheaper (18-fold) copper sulfate when trying to cure catfish that are infected with Ich. This accomplishment is not linked to a milestone of the current Project Plan; however, it can be linked to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

COLUMNARIS DISEASE MODEL DEVELOPED FOR CHANNEL CATFISH: Columnaris is the second most costly disease to the channel catfish industry. Scientists at the HKD Stuttgart National Aquaculture Research Center induced the disease through waterborne exposure of the bacteria to channel catfish after abrading the skin. Infected fish exhibited 95-100% mortalities and clinical signs or lesions that closely resembled a natural infection. This accomplishment provides an alternate columnaris disease model for efficacy testing of potential therapeutants. This accomplishment can be linked to a Year 2 (FY2006) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

ACUTE TOXICITY OF PRAZIQUANTEL DETERMINED FOR GOLDEN SHINERS AND GRASS CARP: Tapeworms not only affect the health of fish but impact fish sales and many states do not allow importation unless the fish are tapeworm-free. The 24- and 96-h toxicities were determined by scientists at the HKD Stuttgart National Aquaculture Research Center. This accomplishment establishes a safety margin between safe/effective treatment and potentially fish-toxic treatment levels which is an important step in clearance and labeling of any fisheries-use chemical. This accomplishment can be linked to a Year 1 (FY2005) and a Year 2 (2006) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

ROCCAL D-PLUS IS EFFECTIVE DISINFECTANT FOR RED-RIM MELANIA SNAIL: A 100% effective disinfectant treatment for dip-nets was established for the invasive red-rim melania snail that vectors trematodes to wild and cultured fish species and can live on dried surfaces for several days. Compounds such as Roccal have recommended usages for net disinfectants but no treatment times effective for the red-rim melania existed. The treatment rate for several exposure periods was tested by scientists at the HKD Stuttgart National Aquaculture Research Center to determine the treatment duration that would kill 100% of the snails. These findings provide an effective disinfectant with an established rate for use on small fisheries equipment to control the spread of this snail. This accomplishment is not linked to a milestone of the current Project Plan; however, it can be linked to the Integrated Aquatic Animal Health Management component of NP-106 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. This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

DETERMINATION OF FINAL HOSTS FOR SPECIFIC TREMATODES: Trematodes from the genera Bolbophorus, Centrocestus, and Clinostomum were collected from 24 birds; Bolbophorus species have been recovered from several bird species but adult trematodes have only been found in the white pelicans, while numerous Clinostomum trematodes were found in great egrets and great blue herons. Limiting access of these three bird species to fish ponds should help curtail some trematode problems. Several bird species were collected by scientists at the HKD Stuttgart National Aquaculture Research Center, and trematodes were removed from the intestinal tracts of the birds, preserved, and identified in cooperative studies with North Carolina State University, Raleigh, NC. This accomplishment provides farmers with information that keeping white pelicans, great blue herons, and great egrets from farm ponds will lower incidence of these trematodes in cultured fish. This accomplishment can be linked to a Year 3 (FY2007) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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. This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

EQUALLY EFFECTIVE SNAIL CONTROL OBTAINED FROM COPPER SULFATE AND HYDRATED LIME SHORELINE TREATMENTS: This research addresses the efficacy of two pond-shoreline treatments for control of snails that vector trematodes to farm-raised fish. Treatments results from the studies were compared by scientists at the HKD Stuttgart National Aquaculture Research Center. Pond water quality, physical structure of the pond, and available equipment for application become the determinative factors in which chemical should be used. This accomplishment provides information to farmers about 2 treatments that are available to reduce snail numbers and the ensuing trematode infection, which means reduced fish losses and greater economic benefits to fish producers. This accomplishment can be linked to a Year 2 (FY2006) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

ESTABLISHED STRAIN DIFFERENCES IN COPPER TOXICITY TO ICHTHYOPHTHIRIUS MULTIFILIIS THERONTS: This research addresses strain differences in copper toxicity that may be caused by genetic or environmental factors. Two serological strains of free-swimming Ich theronts were exposed to concentrations of copper in 96-well plates at two different total alkalinities and observed for 4 h by scientists at the HKD Stuttgart National Aquaculture Research Center. The impact of this accomplishment is an increased scientific understanding of strain differences when related to toxicity and may lead to more specific therapeutic treatments for Ich control in different environments. This accomplishment is not linked to a milestone of the current Project Plan; however, it can be linked to the Integrated Aquatic Animal Health Management component of NP-106 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'. This accomplishment can be linked to ARS Strategic Plan Objective 3.2 - Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.


4c.List significant activities that support special target populations.
None.


5.Describe the major accomplishments to date and their predicted or actual impact.
This is the second year of the five-year Project. Major accomplishments during the first two years (FY2005 and FY2006) include:

COPPER SULFATE TARGET ANIMAL SAFETY TECHNICAL SECTION ACCEPTED AS COMPLETE BY FDA: The safety of a compound to the target animal must be demonstrated before it can gain FDA-approval. Studies were designed and completed by scientists at the HKD Stuttgart National Aquaculture Research Center, and the final study report was submitted to the FDA on 7/1/04. The study was accepted in a letter dated 5/24/05, but additional information was requested. The technical section was accepted as complete by FDA in a letter dated 4/21/2006 and was determined to represent the safety of copper sulfate to channel catfish. There was no mortality to the test animals and no histological changes due to copper toxicity at five-times the therapeutic dose. Upon completion of the final technical section (environmental assessment), the impact of this accomplishment will be to have a much-needed parasiticide as an FDA-approved aquaculture therapeutant. This accomplishment can be linked to a Year 1 (FY2005) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

OPTIMIZING LIME TREATMENTS TO CONTROL SNAILS THAT VECTOR DISEASE IN CATFISH: An optimum pond-shoreline treatment for slurried hydrated lime to control rams-horn snail populations was determined by scientists at the HKD Stuttgart National Aquaculture Research Center. Rams-horn snails are commonly found in production ponds and vector the catfish trematode that can cause significant losses to the channel catfish industry; few effective control methods for these snails exist. Trials were run at various treatment parameters to determine the best treatment for killing rams-horn snails along the shorelines of ponds; this was done as a subordinate project in conjunction with Mississippi State University, Stoneville, MS. The impact of this accomplishment is that a protocol is available to farmers that can greatly reduce the number of rams-horn snails vectoring disease to catfish in production ponds. This accomplishment can be linked to a Year 1 (FY2005) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

DNA SEQUENCE METHOD FOR AQUATIC EPIDEMIOLOGY: Restriction fragment polymorphism (RFLP) and sequencing methods of the 16S rRNA gene and the 16-23S rDNA spacer were developed by scientists at the HKD Stuttgart National Aquaculture Research Center as an epidemiological tool for bacterial columnaris (Flavobacterium columnare) outbreaks in aquatic species. A technique does not exist to compare genotypes of this bacteria; this method has the advantage of being universal and capable of comparing the genotypes from different geographic locations. The method was used to show the correspondence between the genotypes of isolates in North America to those in Asia and Europe and for the first time demonstrate the presence of genotype III in the U.S. The impact of this accomplishment is that with the global development of fish farming and the increased movement of fish between countries, this epidemiological tool will be indispensable in protecting the U.S. from possible introduction of new genotypes of this pathogen. This accomplishment is not linked to a milestone of the current Project Plan; however, it can be linked to the Integrated Aquatic Animal Health Management component of NP-106 addressed in "Epidemiology" goals to "Develop methods to assess risk factors associated with the economically important pathogens of aquatic animals" and to "Carry out basic epidemiology studies to identify disease prevalence, incidence, courses and origin of economically important aquatic animal pathogens". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

EFFICACY OF FLORFENICOL AGAINST STREPTOCOCCUS INIAE INFECTION IN HYBRID STRIPED BASS DEMONSTRATED: The survival of the hybrid striped bass industry in the US is closely linked to the ability to control this bacterial infection. Scientists at the HKD Stuttgart National Aquaculture Research Center demonstrated that florfenicol increased the survival of infected fish from 4% to 94%. This accomplishment provides critical data to support the future FDA-approval of florfenicol against this bacterial infection in hybrid striped bass. This accomplishment can be linked to a Year 2 (FY2006) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

DETERMINED DOSE OF COPPER SULFATE TO CONTROL FUNGUS ON CHANNEL CATFISH EGGS: This research addresses egg mortality from fungus in catfish hatcheries. A range-finding study by scientists at the HKD Stuttgart National Aquaculture Research Center determined that treating catfish eggs daily with 10 ppm copper sulfate until eyes develop will prevent fungus from growing and destroying the eggs in high alkalinity/moderate hardness water at 74 degrees F. This accomplishment will provide direct benefits through increased survival rates in catfish hatcheries and will economically benefit the industry; this research is also required by FDA for a future label claim. This accomplishment can be linked to a Year 3 (FY2007) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

EFFECTIVENESS OF SOLID AND LIQUID FORMULATIONS OF COPPER SULFATE FOR CONTROLLING ICHTHYOPHTHIRIASIS DETERMINED: This research addresses claims that commercial liquid copper formulations are more effective at controlling Ichthyophthiriasis caused by Ichthyophthirius multifiliis (Ich) than copper sulfate. The acute toxicity of copper sulfate crystals and a liquid copper sulfate formulation to channel catfish and free-swimming Ich was determined in low and high alkalinity waters by scientists at the HKD Stuttgart National Aquaculture Research Center in cooperative studies with the University of Arkansas at Pine Bluff, Pine Bluff, AR. The impact of this accomplishment will be directly seen as fish-farmers can use much cheaper (18-fold) copper sulfate when trying to cure catfish that are infected with Ich. This accomplishment is not linked to a milestone of the current Project Plan; however, it can be linked to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

COLUMNARIS DISEASE MODEL DEVELOPED FOR CHANNEL CATFISH: Columnaris is the second most costly disease to the channel catfish industry. Scientists at the HKD Stuttgart National Aquaculture Research Center induced the disease through waterborne exposure of the bacteria to channel catfish after abrading the skin. Infected fish exhibited 95-100% mortalities and clinical signs or lesions that closely resembled a natural infection. This accomplishment provides an alternate columnaris disease model for efficacy testing of potential therapeutants. This accomplishment can be linked to a Year 2 (FY2006) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

ACUTE TOXICITY OF PRAZIQUANTEL DETERMINED FOR GOLDEN SHINERS AND GRASS CARP: Tapeworms not only affect the health of fish but impact fish sales, and many states do not allow importation unless the fish are tapeworm-free. The 24- and 96-h toxicities were determined by scientists at the HKD Stuttgart National Aquaculture Research Center. This accomplishment establishes a safety margin between safe/effective treatment and potentially fish-toxic treatment levels, which is an important step in clearance and labeling of any fisheries-use chemical. This accomplishment can be linked to a Year 1 (FY2005) and a Year 2 (2006) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

ROCCAL D-PLUS IS EFFECTIVE DISINFECTANT FOR RED-RIM MELANIA SNAIL: A 100% effective disinfectant treatment for dip-nets was established for the invasive red-rim melania snail that vectors trematodes to wild and cultured fish species and can live on dried surfaces for several days. Compounds such as Roccal have recommended usages for net disinfectants, but no treatment times effective for the red-rim melania existed. The treatment rate for several exposure periods was tested by scientists at the HKD Stuttgart National Aquaculture Research Center to determine the treatment duration that would kill 100% of the snails. These findings provide an effective disinfectant with an established rate for use on small fisheries equipment to control the spread of this snail. This accomplishment is not linked to a milestone of the current Project Plan; however, it can be linked to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

DETERMINATION OF FINAL HOSTS FOR SPECIFIC TREMATODES: Trematodes from the genera Bolbophorus, Centrocestus, and Clinostomum were collected from 24 birds; Bolbophorus species have been recovered from several bird species but adult trematodes have only been found in the white pelicans, while numerous Clinostomum trematodes were found in great egrets and great blue herons. Limiting access of these three bird species to fish ponds should help curtail some trematode problems. Several bird species were collected by scientists at the HKD Stuttgart National Aquaculture Research Center, and trematodes were removed from the intestinal tracts of the birds, preserved, and identified in cooperative studies with North Carolina State University, Raleigh, NC. This accomplishment provides farmers with information that keeping white pelicans, great blue herons, and great egrets from farm ponds will lower incidence of these trematodes in cultured fish. This accomplishment can be linked to a Year 3 (FY2007) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

EQUALLY EFFECTIVE SNAIL CONTROL OBTAINED FROM COPPER SULFATE AND HYDRATED LIME SHORELINE TREATMENTS: This research addresses the efficacy of two pond-shoreline treatments for control of snails that vector trematodes to farm-raised fish. Treatments results from the studies were compared by scientists at the HKD Stuttgart National Aquaculture Research Center. Pond water quality, physical structure of the pond, and available equipment for application become the determinative factors in which chemical should be used. This accomplishment provides information to farmers about 2 treatments that are available to reduce snail numbers and the ensuing trematode infection which means reduced fish losses and greater economic benefits to fish producers. This accomplishment can be linked to a Year 2 (FY2006) milestone of the Project Plan and also to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

ESTABLISHED STRAIN DIFFERENCES IN COPPER TOXICITY TO ICHTHYOPHTHIRIUS MULTIFILIIS THERONTS: This research addresses strain differences in copper toxicity that may be caused by genetic or environmental factors. Two serological strains of free-swimming Ich theronts were exposed to concentrations of copper in 96-well plates at two different total alkalinities and observed for 4 h by scientists at the HKD Stuttgart National Aquaculture Research Center. The impact of this accomplishment is an increased scientific understanding of strain differences when related to toxicity and may lead to more specific therapeutic treatments for Ich control in different environments. This accomplishment is not linked to a milestone of the current Project Plan; however, it can be linked to the Integrated Aquatic Animal Health Management component of NP-106 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". This accomplishment can be linked to ARS Strategic Plan Objective 3.2: Develop and Deliver Science-Based Information and Technologies to Reduce the Number and Severity of Agricultural Pest, Insect, Weed, and Disease Outbreaks and specifically Performance Measures 3.2.1 and 3.2.3.

The potential customers of this 5-year Project are fish farmers of cultured hybrid striped bass, catfish, tilapia, and baitfish species. 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 also benefit.

Attaining the objectives of this 5-year Project 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.

Potential impact of this 5-year Project 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.


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.


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 Press:

Gaunt, P., Schnick, R. 2005. Industry researchers gather to discuss aquaculture drug status. The Catfish Journal 20(2):21.

Mitchell, A.J., Kelly, A.M. 2006. The public sector role in the establishment of grass carp in the United States. Fisheries 31(3):113-121.

AADAP (Aquatic Animal Drug Approval Partnership) Newsletter. March 2006. Aquaculture America 2006 Highlights. 2(2):3-4.

DeWitt Era-Enterprise Newspaper. July 6, 2006. Curing a really Ich-y problem. 124(6):1-2.

AADAP (Aquatic Animal Drug Approval Partnership) Newsletter. June 2006. Aquaculture Drug Researchers receive FDA Award. 2(3):1.

AADAP (Aquatic Animal Drug Approval Partnership) Newsletter. June 2006. The National Aquaculture Drug Research Forum. 2(3):3-4.

AADAP (Aquatic Animal Drug Approval Partnership) Newsletter. June 2006. Roz's Corner. 2(3):6.

The Catfish Journal. July 2006. Aquaculture researchers cited by FDA. 19(11):14.


Review Publications
Darwish, A.M., Ismaiel, A.A. 2005. Genetic diversity of flavobacterium columnare examined by restriction fragment length polymorphism and sequencing of the 16s ribosomal RNA gene and the 16s-23s RDNA spacer. Molecular and Cellular Probes. 19:267-274.

Mitchell, A.J. 2005. A simple assay to compare zeolite ammonia control properties. North American Journal of Aquaculture. 67:18-22.

Mitchell, A.J., Goodwin, A.E., Levy, M.G. 2006. Bolbophorus infections in cultured fathead minnows. Journal of Aquatic Animal Health. 18:55-57.

Straus, D.L. 2006. Species sensitivity to copper: acute toxicity to channel catfish and sunshine bass. Journal of Applied Aquaculture. 18(1):88-99.

Straus, D.L., Chambers, J.E. 2006. Effects of piperonyl butoxide on the metabolism of DEF (S,S,S-tributyl phosphorotrithioate) in fingerling channel catfish. Toxicology Mechanisms and Methods. 16(4):235-239.

Darwish, A.M., Hobbs, M.S. 2005. Laboratory efficacy of amoxicillin for the control of Streptococcus iniae infection in blue tilapia [abstract]. 30th Annual Eastern Fish Health Workshop. p. 83.

Darwish, A.M., Ismaiel, A.A. 2005. Genetic diversity of flavobacterium columnare examined by restriction fragment length polymorphism and sequencing of the 16s ribosomal RNA gene and the 16s-23s rDNA spacer [abstract]. American Fisheries Society Annual Meeting. p. 4.

Darwish, A.M., Straus, D.L., Griffin, B.R. 2005. Assessment of copper sulfate as therapeutant in channel catfish [abstract]. Aquaculture America 2005 Book of Abstracts. p. 95.

Mitchell, A.J. 2005. Centrocestiasis: A serious gill trematode problem in cultured and wild fishes [abstract]. Book of Abstracts, World Aquaculture Society. p. 283.

Mitchell, A.J., Kellly, A.M. 2005. The public sector role in the establishment of grass carp in the United States [abstract]. American Fisheries Society Annual Meeting. p. 1147.

Mitchell, A.J. 2006. The effect of chemical treatments on Melanoides tuberculatus, a snail that vectors an important fish trematode [abstract]. Aquaculture America 2006 Book of Abstracts. p. 190.

Mitchell, A.J. 2006. Grass carp in the United States: 1963 to the present [abstract]. Aquaculture America 2006 Book of Abstracts. p. 189.

Mitchell, A.J., Wise, D.J., Snyder, S.G. 2006. Optimizing slurried-hydrated lime pond-shoreline treatments for aquatic snails vectoring trematodes to cultured fish [abstract]. Catfish Culture Research Symposium. p. 30.

Mitchell, A.J. 2005. The control of fish parasites and the eradication of Asian tapeworm infections in grass carp using praziquantel bath treatments [abstract]. Annual Eastern Fish Health Workshop. p. 30.

Mitchell, A.J. 2005. Centrocestus formosanus in cultured and wild fishes: Impact on fish, distribution in the United States, and host information [abstract]. American Fishery Society (Fish Health Section) Proceedings. p. 23.

Mitchell, A.J. 2006. The big belly blues [abstract]. Annual Eastern Fish Health Workshop. p. 62.

Mitchell, A.J. 2006. From Leidy to Snieszko: Pioneers of fish health in the US (1850 to 1950) [abstract]. Annual Eastern Fish Health Workshop. p. 51.

Straus, D.L. 2005. Status of potassium permanganate initial label claim [abstract]. Drug Approval Coordination Workshop Meeting Abstract. 11:114.

Straus, D.L. 2005. Status of copper sulfate initial label claim [abstract]. Drug Approval Coordination Workshop Meeting Abstract. 11:112.

Straus, D.L. 2005. Status of aquaflor initial label claim [abstract]. Drug Approval Coordination Workshop Meeting Abstract. 11:58.

Straus, D.L. 2006. Acute toxicity of copper sulfate to channel catfish fry at various ages: Well water vs. diluted well water [abstract]. Aquaculture America 2006 Book of Abstracts. p. 304.

Last Modified: 8/30/2014
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