Source: MISSISSIPPI STATE UNIV submitted to
MANAGEMENT OF FISH-BORNE TREMATODES IN POND-RAISED ICTALURID CATFISH
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
1026282
Grant No.
2021-70007-34784
Cumulative Award Amt.
$310,000.00
Proposal No.
2020-06948
Multistate No.
(N/A)
Project Start Date
Sep 1, 2021
Project End Date
Aug 31, 2024
Grant Year
2021
Program Code
[AQUA]- Aquaculture Research
Project Director
Rosser, T. G.
Recipient Organization
MISSISSIPPI STATE UNIV
(N/A)
MISSISSIPPI STATE,MS 39762
Performing Department
CVM Basic Science Department
Non Technical Summary
The production of pond-raised catfish is the largest sector of the U.S. aquaculture industry and a vital component of several southeastern states. Mortality resulting from direct exposure to waterborne stages and lost production associated with parasite induced anorexia result in significant monetary losses. Management is dependent on host exclusion and eradication to prevent transmission of these parasites in catfish production systems and mitigation efforts are estimated to cost producers millions of dollars annually. Catfish producers and industry leaders emphasize a critical need for research focused on increasing our understanding of trematode biology and development of more efficient/cost effective management strategies. However, the complex life cycles for many trematodes affecting catfish are largely unknown. We propose an integrated study to identify all potential vectors, through surveys of trematode life stages in avian, molluscan, and fish hosts using a polyphasic approach employing classical parasitology, molecular biology and next-generation sequencing. Most importantly, we will establish prophylactic treatments using a two-pronged approach targeting larval and juvenile snails, as well as larval trematode stages (eggs and miracidia). Prophylactic eradication of juvenile snails and larval trematode stages will disrupt trematode life cycles, and in turn, prevent infections in fish before significant losses can occur and treatment options become limited. The objectives proposed herein align with the USDA Special Research Grants Program for Aquaculture, specifically the funding of applied research focused on critical disease issues impacting commercial aquaculture species. The attached letters from industry stakeholders attest to the urgency and importance of the research outlined in this proposal to ensure the sustainability and profitability of U.S. catfish aquaculture.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
31337191110100%
Knowledge Area
313 - Internal Parasites in Animals;

Subject Of Investigation
3719 - Other cultured finfish;

Field Of Science
1110 - Parasitology;
Goals / Objectives
The overall goal of this project is to provide U.S. catfish producers with management strategies to mitigate losses associated with fish-borne trematodes. This will be accomplished through the use of next-generation sequencing technology to generate complete ribosomal and mitochondrial gene regions of adult trematodes collected the fish-eating birds that introduce them into catfish production systems for the inference of unknown trematode life cycles. These data will be used to infer life cycles by making direct comparisons to sequence data obtained from the molluscan and fish stages of these parasites. By elucidating the life cycle, producers will be able to establish pest management programs targeted towards exclusion of the bird and chemical eradication of the snail hosts vectoring these trematodes. Further work will investigate the toxicity of low-level doses of copper sulfate against developmental stages of both the snail and larval trematodes. As the industry has increased its production of hybrid catfish, the impacts of many infectious diseases, including trematode parasites remain understudied and require industry wide reassessment. We aim to investigate the trematode parasites present in hybrid catfish and determine impacts on fish health through experimental challenges and comparative studies with channel catfish. The concerted efforts of these objectives will offer catfish producers much needed data to better manage the industry wide burden of fish-borne trematodes.
Project Methods
Efforts: Elucidation these trematode life cycles will be achieved through the generation and comparison of molecular DNA sequence data (rDNA and mitochondrial DNA) from all stages collected from each host. Through this approach we avoid the labor intensive and potential unsuccessful maintenance and transmission of parasites through experimental infections of all hosts. This is also sometimes potentially unsuccessful if the wrong host or a surrogate host is used. Through the study of adult trematodes collected from piscivorous birds of a previous project, cercariae from field collections of snail hosts at farms affected by this parasite, and metacercariae collected from the initial diagnostic cases of this parasite we will be able to propose management options to catfish producers.Evaluated: The impact of this project will be measured through the publication of conference abstracts and publications in scholarly peer-reviewed journals relevant to the field. Additionally, its direct importance will be noted by the occurrence of diagnostic case submissions or industry reports of mortalities associated with these trematodes.

Progress 09/01/21 to 08/31/24

Outputs
Target Audience:In an applied aspect, the target audience will include producers of pond-raised ictalurid catfish and fish health specialists throughout the U.S. as the bird and snail hosts of these parasites are widely distributed. The parallels and techniques used in this project will be comparable and capable of being used by fish producers and fish health specialists on a global scale as the basic trematode life cycle is largely the same for most fish-borne trematodes. Translocation of nonnative fish and the migration of birds have distributed some of these parasites across continents, so these techniques and goals have a global significance for any aquaculture industry, but especially developing ones where any infectious disease has the potential to diminish growth. From a basic parasitology aspect, the molecular data and ecological data also have global importance. Data (sequence and parasitological) from previous work by our group receives notice and citation often within several months by other global fish health professionals/parasitologists. Changes/Problems:Rapid adoption of preventative strategies stemming from this and previous work, while beneficial for production, resulted in difficulty in the efforts of Objective 3. Experimental trials to examine the pathology associated with infections in fish rely on outbreaks where naturally infected snail hosts can be collected and used. With producers following industry recommendations and outbreaks of trematode infections lessened, successful collection of infected snail hosts to conduct experimental infections was not achieved during the funding period. However, we intend to pursue these efforts in the future. What opportunities for training and professional development has the project provided?Mentoring and sucessfulcompletion of one masters student and the training and involvement in research of 2 undergraduates. How have the results been disseminated to communities of interest?Data and outcomes have been shared with catfish producers through presentations at annual Catfish Producers Meeting held in Stoneville, Mississippi. Here producers receive direct updates on the activities of research dedicated towards bettering the U.S. catfish industry in an open forum. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Major activities completed: Next generation sequencing of the trematode species predominantly found in catfish, avian and molluscan hosts common to catfish ponds have been sequenced and are OxFord Nanopore data are being validated against publicly available molecular data and with traditional Sanger sequencing. These data have been used to establish a link between all hosts in the life cycle of a second species of Bolbophorus that occurs within the American White Pelicans (AWPE). These data will be used to describe this novel species and molecular data generated from Objective 1 have linked the avian final host (AWPEs), ramshorn snail and forage fish species within catfish ponds as viable hosts in the life cycle of this species. Further work will be done to verify infectivity in catfish and be instrumental in re-enforcing integrated pest management plants to mitigate infections. Complete mitochondrial genomes and ribosomal DNA operons for 4 separate trematodes that infect catfish were generated using Oxford Nanopore sequencing. Refinement of these genomes was achieved by additional Illumina and Sanger sequencing. These datasets will be made available as part of updated descriptions of each parasite species. Data collection began soon after funding in regards to Objective 1 and Objective 2. These objectives are capable of being accomplished given the collection of samples within the Rosser lab from years of prior collection and archiving. Due to COVID-19 limitations and difficulties in finding a student, the Master's student (Logan Robison) funded by this work began in June of 2022. Logan made great strides on this project, specifically with the Objective 3 goals. Our data suggest that trematode eggs of multiple spp. (Drepanocephalus spathans, Austrodiplostomum compactum) all of which infect commercially raised catfish are not susceptible to copper sulfate at a range of doses designed to be safe for use in catfish ponds (0.10, 0.19, 0.38, 0.76, 1, 2, and 3 mg/L Cu). The percentage of trematode eggs maintained at doses of 0.10-0.76 mg/L Cu, did not differ from unexposed controls, after observation for 40 days at 26 C. However, eggs of Drepanocephalus spathans maintained at concentrations of 1.0-3 mg/L Cu had a significantly lower hatch rate compared to untreated controls. While these higher doses appeared to preclude trematode egg hatching, application of copper at these rates must be used cautiously in catfish ponds. This is dependent on pond conditions at the time of treatment. Copper toxicity concerns are increased during the summer months when water temperatures are higher and snail populations are at their peak. However, application during spring months when water temperatures are lower and copper toxicity risks lessen, producers may pursue doses efficacious at eradicating both snail intermediate hosts and egg stages of trematodes. Additionally, these experiments resulted in a refined timeline of trematode egg development under varying temperature conditions to provide a putative timeline of events for understanding when snail hosts are likely becoming infected in catfish production systems.

Publications

  • Type: Peer Reviewed Journal Articles Status: Accepted Year Published: 2024 Citation: Nguyen JA, Woodyard ET, McAllister CT, Marcquenski SV, Rose D, Slifka CM, Robison LRS, Griffin MJ, Rosser TG. Morphological and molecular data establishes Clinostomum dolichorchum n. sp. (Digenea: Clinostomidae) in the great blue heron Ardea herodias L. and American bullfrog Rana catesbeiana Shaw. Syst Parasitol. 2024 May 25;101(4):42. doi: 10.1007/s11230-024-10166-z.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2022 Citation: Jonah A. Nguyen, Bradley M. Richardson, Ethan T. Woodyard, Justin M. Stilwell, Celene M. Slifka, Divya Rose, Chris McAllister, Thomas G. Rosser. (2022) A morphological and molecular comparison of Clinostomum metacercariae and adults of the United States. International Symposium on Aquatic Animal Health. September 2022. Santiago de Chile.
  • Type: Theses/Dissertations Status: Other Year Published: 2024 Citation: Robison, Logan R. S. 2024. Evaluation of copper sulfate treatment to preclude hatching of trematode eggs, with notes on the influence of temperature on miracidial development and hatching of Drepanocephalus spathans. Mississippi State University. Thesis, pp. 57.


Progress 09/01/22 to 08/31/23

Outputs
Target Audience:In an applied aspect, the target audience will include producers of pond-raised ictalurid catfish and fish health specialists throughout the U.S. as the bird and snail hosts of these parasites are widely distributed. The parallels and techniques used in this project will be comparable and capable of being used by fish producers and fish health specialists on a global scale as the basic trematode life cycle is largely the same for most fish-borne trematodes. Translocation of nonnative fish and the migration of birds have distributed some of these parasites across continents, so these techniques and goals have a global significance for any aquaculture industry, but especially developing ones where any infectious disease has the potential to diminish growth. From a basic parasitology aspect, the molecular data and ecological data also have global importance. Data (sequence and parasitological) from previous work by our group receives notice and citation often within several months by other global fish health/parasitologists. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?The results have been presented at different meetings and conferences throughout the year. What do you plan to do during the next reporting period to accomplish the goals?Further work will be done to verify infectivity in catfish and be instrumental in re-enforcing integrated pest management plants to mitigate infections.

Impacts
What was accomplished under these goals? Major activities completed: Next generation sequencing of the trematode species predominantly found in catfish, avian and molluscan hosts common to catfish ponds have been sequenced and are OxFord Nanopore data are being validated against publicly available molecular data and with traditional Sanger sequencing. These data have been used to establish a link between all hosts in the life cycle of a second species of Bolbophorus that occurs within the American White Pelicans (AWPE). These data will be used to describe this novel species and molecular data generated from Objective 1 have linked the avian final host (AWPEs), ramshorn snail and forage fish species within catfish ponds as viable hosts in the life cycle of this species.

Publications

  • Type: Journal Articles Status: Under Review Year Published: 2023 Citation: Jonah A. Nguyen, Ethan T. Woodyard, Chris T. McAllister, Susan V. Marcquenski, Divya Rose, Celene M. Slifka, Logan R. S. Robison, Matt J. Griffin, T. Graham Rosser. Morphological and molecular data establishes Clinostomum dolichorchum n. sp. (Digenea: Clinostomidae) in the great blue heron Ardea herodias L. and American bullfrog Lithobates catesbeianus (Shaw).  Under internal review with intentions to submit to Systematic Parasitology


Progress 09/01/21 to 08/31/22

Outputs
Target Audience:In an applied aspect, the target audience will include producers of pond-raised ictalurid catfish and fish health specialists throughout the U.S. as the bird and snail hosts of these parasites are widely distributed. The parallels and techniques used in this project will be comparable and capable of being used by fish producers and fish health specialists on a global scale as the basic trematode life cycle is largely the same for most fish-borne trematodes. Translocation of nonnative fish and the migration of birds have distributed some of these parasites across continents, so these techniques and goals have a global significance for any aquaculture industry, but especially developing ones where any infectious disease has the potential to diminish growth. From a basic parasitology aspect, the molecular data and ecological data also have global importance. Data (sequence and parasitological) from previous work by our group receives notice and citation often within several months by other global fish health/parasitologists. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?The results have been presented at the International Symposium on Aquatic Animal Health in September 2022. Also, data will be presented in the Spring of 2023. What do you plan to do during the next reporting period to accomplish the goals?Further work will be done to verify infectivity in catfish and be instrumental in re-enforcing integrated pest management plants to mitigate infections.

Impacts
What was accomplished under these goals? Major activities completed: Next generation sequencing of the trematode species predominantly found in catfish, avian and molluscan hosts common to catfish ponds have been sequenced and are OxFord Nanopore data are being validated against publically available molecular data and with traditional Sanger sequencing. These data have been used to establish a link between all hosts in the life cycle of a second species of Bolbophorus that occurs within the American White Pelicans (AWPE). These data will be used to describe this novel species and molecular data generated from Objective 1 have linked the avian final host (AWPEs), ramshorn snail and forage fish species within catfish ponds as viable hosts in the life cycle of this species. Further work will be done to verify infectivity in catfish and be instrumental in re-enforcing integrated pest management plants to mitigate infections.

Publications

  • Type: Conference Papers and Presentations Status: Other Year Published: 2022 Citation: Jonah A. Nguyen, Bradley M. Richardson, Ethan T. Woodyard, Justin M. Stilwell, Celene M. Slifka, Divya Rose, Chris McAllister, Thomas G. Rosser. Morphological and Molecular Comparison of Clinostomum Metacercariae and Adults of the United States. 2022. International Symposium on Aquatic Animal Health.