Research Project: New Approaches to Managing Catfish Health in Aquaculture

Location: Warmwater Aquaculture Research Unit

2025 Annual Report

Objectives
1. Identify emergent pathogens in catfish aquaculture and develop disease diagnostic methodologies for use in field surveillance studies. 1.1. Identify emergent pathogens in catfish aquaculture and develop disease diagnostic methodologies for field surveillance studies. 1.2. Characterize and evaluate pathogenesis of emergent diseases and fulfillment of Koch’s postulates or River’s postulate for newly recognized or emergent pathogens. 1.3. Develop rapid diagnostic tests and ELISA procedures to determine total and antigen specific antibody for epidemiological studies. 1.4. Develop primary catfish cell lines for identification and confirmation of fish viruses. 2. Optimize treatments and management strategies to minimize infectious diseases in catfish aquaculture. 2.1. Optimize Edwardsiella (E.) ictaluri vaccine delivery, evaluate cross protective potential of E. ictaluri vaccine against E. piscicida. 2.2. Role of other myxozoans (non-H. ictaluri) and intraspecific variability of oligochaete hosts in occurrence of proliferative gill disease (PGD) in channel and hybrid catfish. 2.3. Role of iron fortified diets and occurrence of bacterial infections in channel and hybrid catfish. 2.4. Evaluation of the pathophysiological effects of Bolbophorus damnificus (trematode) in hybrid and channel catfish. 3. Determine the epidemiology of infectious diseases in catfish aquaculture and conduct economic evaluations of disease management strategies. 3.1. Significance of genetic E. piscicida variants recovered from commercially cultured hybrid and channel catfish. 3.2. Epidemiology of A. hydrophila infections in catfish aquaculture; predictive modeling to determine risk factors. 3.3. Spatio-temporal survey of channel catfish virus (CCV) isolates and evaluation of trends in the occurrence and virulence of different genetic strains of CCV in channel and hybrid catfish. 3.4. Evaluate disease transmission of emergent Vibrio spp. infections in hatchery fry. 3.5. Economic evaluation of a live, attenuated E. ictaluri vaccine in commercial fingerling and foodfish production.

Approach
In the United States, pond production of catfish ranks as the leading aquaculture species in terms of farm gate value. Health management strategies, technologies, and bio-security plans that are environmentally safe are necessary to help mitigate disease-related losses. There is presently a lack of validated technologies for early and rapid detection of pathogens, disease prevention, and treatment of diseases in catfish aquaculture, which has hindered the growth and profitability of the industry. Validated diagnostic tools for use in production systems to detect the disease agents in a rapid fashion are needed. In addition to the need for diagnostics, developing effective control strategies to manage disease is a priority, given only a few drugs are available for the treatment of sick fish. Further research will develop molecular based diagnostic tools used in to monitor potential emergent pathogens, optimize vaccination strategies for control of bacterial infections, determine the epidemiology of priority infectious diseases and assess costs and benefits of disease management strategies in hybrid and channel catfish aquaculture. We will identify emergent pathogens in catfish aquaculture and develop disease diagnostic methodologies for use in field surveillance studies. Specifically, we will characterize and evaluate pathogenesis of emergent diseases and fulfillment of Koch’s postulates or River’s postulate for newly recognized or emergent pathogens, develop rapid diagnostic tests and ELISA procedures to determine total and antigen specific antibody for epidemiological studies, and develop primary catfish cell lines for identification and confirmation of fish viruses. To improve disease management strategies in catfish aquaculture we will optimize Edwardsiella (E.) ictaluri vaccine delivery and evaluate cross protective potential of E. ictaluri vaccine against E. piscicida, determine the role of other myxozoans (non-H. ictaluri) and intraspecific variability of oligochaete hosts in occurrence of proliferative gill disease (PGD) in channel and hybrid catfish, determine the role of iron fortified diets and occurrence of bacterial infections in channel and hybrid catfish, and evaluate the pathophysiological effects of Bolbophorus damnificus (trematode) in hybrid and channel catfish. In order to determine the epidemiology of infectious diseases in catfish aquaculture and conduct economic evaluations of disease management strategies we will determine the significance of genetic E. piscicida variants recovered from commercially cultured hybrid and channel catfish, determine the epidemiology of atypical Aeromonas hydrophila (aAh) infections in catfish aquaculture, perform a spatio-temporal survey of channel catfish virus (CCV) isolates and evaluate trends in the occurrence and virulence of different genetic strains of CCV in channel and hybrid catfish, evaluate disease transmission of emergent Vibrio spp. infections in hatchery fry, and evaluate economic impact of a live, attenuated E. ictaluri vaccine in commercial fingerling and foodfish production.

Progress Report
Clinical Research Under Objective 1, the Aquatic Research and Diagnostic Laboratory (ARDL) provides diagnostic services to support the US commercial catfish industry. This service offers valuable insights into disease trends and helps identify emerging pathogens and research. From 2020-2024, the ARDL received 3,282 cases submitted by producers and researchers for diagnostics and water quality analysis. The ARDL was crucial in investigating the prevalence and virulence of columnaris-causing bacteria in the U.S. catfish industry, supplying critical diagnostic case material to identify and characterize Flavobacterium species. Increased culture of hybrid catfish led to the emergence of pathogens not typically seen in channel catfish, most notably Edwardsiella piscicida, which became a significant pathogen in hybrids. We also identified massive branchial henneguyosis, an emerging gill disease in hybrid catfish caused by heavy infections with Henneguya exilis, distinct from the more familiar proliferative gill disease caused by Henneguya ictaluri. Metagenomic and in situ hybridization studies showed these conditions are associated with different myxozoan communities which may increase morbidity in affected fish. Based on diagnostic submissions, antibiotic resistance notably declined over the past five years, coinciding with the initiation of an experimental Edwardsiella ictaluri vaccine program, which reduced antibiotic use within the industry. A fish-associated strain of Group C Streptococcus dysgalactiae was identified as a new disease agent in catfish broodstock. Recent data indicates pathogen affects egg quality and hatching rates in hybrid catfish eggs. We now focus on developing a vaccine and management strategies to control streptococcal infections in channel catfish broodstock used to produce hybrid catfish. Other microbes of interest are Vibrio cholerae (in hatchery fry) and Yersinia ruckeri (in hybrid catfish). These pathogens are not widespread but are monitored as potential emergent pathogens. Genomic assessments of V. cholerae isolated from mortality events in hatcheries revealed they were non-toxigenic, lacking the CTX toxin. Treatment and Epidemiology of Infectious Diseases (Objectives 2 and 3). The pathology of Edwardsiella tarda, E. piscicida, and E. anguillarum infections was assessed, including channel catfish, blue catfish, and hybrids. The most severe pathology and mortality occurred in fish challenged with E. piscicida, confirming its higher virulence in commercially important catfish. In contrast, E. tarda and E. anguillarum pose minimal risk. Hybrid catfish were significantly more susceptible to E. piscicida than channel catfish, consistent with diagnostic findings from commercial farms. Family-level evaluations revealed the Delta Select line of channel catfish exhibited similar resistance to E. ictaluri as the non-select line but demonstrated improved resistance to E. piscicida. Dietary probiotic supplementation after antibiotic therapy can improve survival in channel catfish challenged with E. ictaluri, likely by supporting recovery of gut microbes. Cross-protection studies revealed fish vaccinated with a live-attenuated E. ictaluri vaccine were protected against multiple variants of E. piscicida, suggesting the presence of shared and conserved antigens between these pathogens that can be targeted by polyvalent vaccines. Serological studies also showed fish vaccinated against E. ictaluri produced elevated IgM antibodies against both E. ictaluri and E. piscicida further supporting cross-protection. The myxozoan Henneguya ictaluri causes proliferative gill disease (PGD) in channel and hybrid catfish, leading to significant losses. The parasite has a complex life cycle involving fish as an intermediate host and the aquatic oligochaete Dero digitata as the definitive host. PGD outbreaks occur seasonally, with parasite levels peaking in early spring, coinciding with pond restocking. Thus, most losses occur when fish are introduced into ponds with elevated parasite levels. We developed a PGD risk assessment model, based on qPCR assessment of environmental DNA, to predict fish losses based on molecular assessment of parasite levels when stocking. The model categorizes risk as low, moderate, or high and helps producers determine when ponds are safe to stock. Producers using this model successfully eliminated PGD-related losses at stocking, saving an estimated $25,000 to $50,000 annually in replacement fish costs. In response to producer queries, this model was also used to determine potential benefits of stocking larger fingerlings to reduce PGD losses. Data indicated no benefit from investing in and stocking larger fingerlings (>120 lbs/1000) to offset PGD losses. Hybrid catfish can serve as a dead-end host for H. ictaluri, significantly lowering parasite prevalence in production systems. In experimental ponds, hybrids consistently carried fewer parasites, and genomic studies revealed they promote a different, less harmful myxozoan community. The use of nonictalurid “interceptor” fish further reduced parasite burdens by diverting actinospores away from catfish. Together, these strategies offer practical, science-based solutions to limit outbreaks, directly reduce disease losses, and improve overall profitability for producers. Additionally, new molecular tools such as targeted metagenomics and RNAscope in situ hybridization allow for precise tracking of parasites and rapid evaluation of control measures, supporting more effective and sustainable management of myxozoan diseases in catfish aquaculture. The trematode Bolbophorus damnificus can limit production in US farm-raised catfish. Previous research showed that even mild outbreaks, which may go unnoticed by producers, led to a 60% reduction in net return due to decreased feeding and trematode-induced mortality. During this project, researchers discovered that B. damnificus causes a parasite-induced anemia in catfish, which is less impactful in hybrids. It is more difficult to identify outbreaks in hybrid systems based on fish behavior, causing infections to go unnoticed until fish are turned away at processing plants due to the presence of cysts. While infectivity rates in channel and hybrid catfish are similar, hybrids experience much lower mortality, likely due to greater tolerance of the anemic response caused by infection. Control efforts focus on breaking the parasite’s life cycle by eliminating snail hosts from production ponds. Previous studies revealed multiple low-dose copper sulfate treatments are just as effective as single high doses, improving safety and reducing costs without compromising efficacy. However, preparing copper sulfate solution is labor-intensive and often results in inaccurate dosing, increasing the risk of under- or over-application. Therefore a mechanized granular copper sulfate applicator was developed and tested in both experimental and commercial settings. The system delivers copper crystals uniformly along the pond’s edges in a single pass, improving treatment precision, reducing labor, and enhancing the safety and effectiveness of copper sulfate applications. ARS scientists at Stoneville, Mississippi conducted research to assess the environmental impact of copper sulfate treatments. Experimental ponds were treated with varying copper sulfate levels to evaluate effects on pond organisms and fish production. Copper treatments significantly altered phytoplankton communities, with dose-dependent reductions in Cyanophyta (off-flavor producing algae) and increases in Charophyta (green algae beneficial for oxygen production) compared to untreated controls. Despite these shifts, phytoplankton populations remained stable. At harvest, there were no significant differences in fish production, water quality, or zooplankton communities among treatments. Additionally, higher copper doses (1.0 and 1.5 mg/L) stabilized microbial communities, while control and lower-dose treatments (0.5 mg/L) showed greater fluctuations. Iron supplements, previously shown to mitigate anemia and stimulate red blood cell production, were evaluated for their effects on growth and disease resistance in hybrid catfish. Fish were fed diets containing 500 to 1500 mg/kg of iron. At the end of the trial, dietary iron did not impact growth performance, survival, condition indices, or protein and iron retention, but did increase susceptibility to E. ictaluri infection. Based on these findings, iron supplements are not recommended during fingerling production, when fish are most vulnerable to E. ictaluri infection. An atypical strain of Aeromonas hydrophila (aAh) has been linked to severe losses in the catfish industry. A rapid quantitative PCR method was developed to detect aAh in fish and environmental samples, enabling monitoring of active infections and carrier states. Pond health status influenced which tissue provided the most PCR-positive results: during outbreaks, gill swabs were more effective, while lower intestine swabs better identified carriers in healthy populations. These findings highlight a likely carrier state and suggest that aAh poses minimal risk unless the host is compromised or there is mechanical entry into the bloodstream. Atypical aAh isolates from diagnostic submissions in Mississippi and Alabama were analyzed by PCR and genome sequencing. By 2015, all Alabama cases were linked to the ML09-119 haplotype, while both ML09-119 and S14-452 were found in Mississippi. In the Mississippi Delta, the S14-452 haplotype caused about 20% of cases in 2014 but rose to 100% by 2017, its increased fitness likely due to its complete type VI secretion system (T6SS). This research provided a spatial and temporal overview of the emergence and dominant shift between aAh haplotypes and underscored the importance of pathogen monitoring. Additionally, a killed aAH vaccine offered cross-protection to channel catfish against both strains.

Accomplishments
1. Use of vaccines to control Edwardsiellosis in catfish aquaculture. Catfish aquaculture is plagued by two closely related bacterial species in the genus Edwardsiella, and Edwardsiella ictaluri is the most detrimental bacterial disease affecting channel catfish with most losses occurring during the fingerling stage of production. With increased adoption of hybrid catfish as a production fish, E. piscicida has emerged as a serious threat to hybrid catfish aquaculture. In contrast to E. ictaluri, E. piscicida primarily affects market sized fish incurring significant production costs. Researchers at Stoneville, MS, created a live attenuated vaccine and demonstrated the presence of shared and conserved antigens among E. piscicida and E. ictaluri conferring protection against cross infections. The vaccine and vaccine delivery system are currently used commercially to vaccinate channel and hybrid catfish resulting in increased yield and economics returns in fingerling and food fish production systems. To date, over 300 million catfish fingerlings are vaccinated each year representing approximately 90% of catfish raised in the southeastern United States.

2. Potential of stock rotations to mitigate proliferative gill disease in catfish aquaculture. Proliferative gill disease (PGD) in channel and hybrid catfish is a devastating disease associated with myxozoan parasitism. The causative agent is cited as Henneguya ictaluri, a myxozoan parasite present in nearly all catfish ponds during the spring of the year and can cause catastrophic losses (>90% mortality) in severe outbreaks. Previous research has indicated the hybrid catfish may be a dead-end host in the Henneguya ictaluri life cycle and submissions to the Aquatic Research and Diagnostic Laboratory point to reduced incidence of PGD in hybrid systems. Researchers at Stoneville, MS, challenged channel and hybrid catfish with Henneguya ictaluri and found myxospores maturing in channel catfish from 14-20 weeks post-infection, but no myxospore development in exposed hybrid catfish. This supports previous work by our research group demonstrating the suppression of H. ictaluri life stages in hybrid pond systems. This research suggests hybrid catfish are a dead-end host in the H. ictaluri life cycle, or that development in hybrids is significantly arrested/delayed. This work implies strategic crop rotations between channel and hybrid catfish could be a viable management strategy to minimize incidence of PGD on commercial catfish operations.

3. Development of an Effective Oral Enteric Septicemia of Catfish Vaccination Platform. Enteric septicemia of catfish (ESC) is considered the most problematic bacterial disease affecting the production of catfish fingerlings, but vaccination has proven effective in reducing infections. Scientists in Stoneville, MS, developed the ESC vaccine which increased fingerling production yield resulting in net revenues exceeding $3,500 per hectare. To date, over 90% of catfish fingerlings produced in Mississippi and Arkansas, serving as the primary source of fish raised in the southeastern United states. A patent for the vaccine isolate was granted in 2015 (Patent No. 8,999,319) and the patent for the delivery system granted in 2022 (Patent No. 11,330,833 B2). The vaccine also cross protects against a closely related pathogen E. piscicida affecting primarily hybrid catfish. After continued use as a standard industry practice in the production of hybrid and channel catfish production antibiotic usage has significantly declined along with a dramatic decrease in antibiotic resistance. This significant step in preventative measures maintains the effectiveness of the few antibiotics labeled for use in food fish production.

4. Emergent disease agents and diagnostic trends. The Aquatic Research and Diagnostic Laboratory is a clinical program that provides diagnostic services to support research and the commercial catfish industry. This service offers insights into disease trends, identifies emerging pathogens, and directs resources to pressing industry issues. Antibiotic resistance continues to be a growing threat to the utility of approved medicated feeds. However, compared to previous years, there has been a dramatic reduction in antibiotic resistance, likely related to the recent adoption of an Edwardsiella ictaluri vaccine, developed from the previous NACA. The number of antibiotic cases dropped from 111 in 2019 to 10 in 2024. Several potential emergent pathogens have been identified. Y. ruckeri was isolated from hybrid catfish. Infectivity trials demonstrated a low potential for waterborne transmission, and it is not currently expected to be a significant pathogen. Vibrio cholerae has been isolated from catfish during the hatchery phase of production and raised concerns not only for catfish fry production but also as a zoonotic agent. Research demonstrated that outbreaks were associated with overcrowding and have been resolved through good management practices. Additionally, isolates archived from diagnostic submissions show that the V. cholerae strains lack the cholera toxin genes (CTX) and are consistent with other non-toxigenic strains found in aquatic environments and are part of the normal water flora. As such, V. cholerae affecting hatchery catfish is not considered a contagion or to have zoonotic potential. Group C Streptococcus dysgalactiae has been identified as a new disease agent in catfish brood stock. Molecular analysis has tied these isolates to a discrete fish associated group attributed to disease outbreaks in both marine and freshwater environments, indicating a potential emergence of this fish associated pathogen in US catfish aquaculture.

5. Implementation of a PGD risk assessment model. Proliferative gill disease (PGD) is caused by a ubiquitous myxozoan parasite causing substantial losses in commercially raised catfish. Most losses occur when catfish fingerlings are introduced in grow-out ponds for food fish production. Researchers at Stoneville, MS, developed a PGD risk assessment model to determine the likelihood of fish losses in newly stocked production ponds or when fish are understocked for food fish production. The risk assessment model relies on comprehensive water analysis, utilizing environmental DNA isolation and a quantitative PCR assay specifically developed and validated through this project. By determining the levels of infectious life stages present in the pond water, correlations between parasite levels and mortality events were established. This program has been implemented as a demonstration project on farms where water samples are collected concurrently with sentinel fish exposures to identify ponds that can be safely stocked with minimal risk to fish health. Under this program, producers submit their pond water samples for analysis, and the risk of fish loss is determined based on the parasite levels detected. Ponds with high parasite levels are closely monitored and re-evaluated until the levels fall below a predetermined threshold, thus minimizing losses associated with PGD. The cost of PGD is not known but feedback from one participating producer indicates the program saves between $25,000-50,000 annually by avoiding stocking fish into ponds with lethal parasite levels. By accurately evaluating the parasite levels in pond water, producers can make informed decisions regarding stocking strategies, ultimately minimizing losses, and increasing profitability.

Review Publications
Arun, V., Griffin, M.J., Wise, D.J., White, D., Ford, L., Lopez-Porras, A., Camus, A.C., Hanson, L.A. 2020. Virulence and immunogenicity of blue catfish alloherpesvirus in channel, blue and blue × channel hybrid catfish. Journal of Fish Diseases. 51(3)740-749. https://doi.org/10.1111/jwas.12696.
Gunn, M.A., Allen, P.J., Rosser, T.G., Wise, D.J., Griffin, M.J. 2020. Assessment of Bolbophorus damnificus prevalence and cercariae shedding in Planorbella trivolvis populations in catfish aquaculture ponds. Journal of the World Aquaculture Society. 52(2)395-404. https://doi.org/10.1111/jwas.12756.
Wise, A.L., Lafrentz, B.R., Kely, A.M., Liles, M.R., Griffin, M.J., Beck, B.H., Bruce, T.J. 2023. The Infection Dynamics of Experimental Edwardsiella ictaluri and Flavobacterium covae Coinfection in Channel Catfish (Ictalurus punctatus). Pathogens. 12(3)462. https://doi.org/10.3390/pathogens12030462.
Alberson, N.R., Rosser, T.G., Woodyard, E.T., Khoo, L.H., Baumgartner, W.A., Pote, L.M. 2022. Experimental elucidation of the life cycle of Drepanocephalus spathans (Digenea: Echinostomatidae) with notes on the morphological plasticity of D. spathans in the United States. Journal of Parasitology. 108(2)141-158. https://doi.org/10.1645/19-157.
Kumar, G., Byars, T.S., Greenway, T.E., Aarattuthodiyil, S., Khoo, L.H., Griffin, M.J., Wise, D.J. 2019. Economic assessment of commercial-scale Edwardsiella ictaluri vaccine trials in U.S. catfish industry. Aquaculture Economics & Management. 23(3)254-275. https://doi.org/10.1080/13657305.2019.1632392.
Nguyen, D.T., Lopez-Porras, A., Maranick, D., Hawkins, L., Welch, T.J., Petty, B.D., Ware, C., Griffin, M.J., Soto, E. 2021. Genetic characterization of heterologous Edwardsiella piscicida isolates from diverse fish hosts and virulence assessment in a Chinook salmon Oncorhynchus tshawytscha model. Journal of Fish Diseases. 44(12):1959-1970. https://doi.org/10.1111/jfd.13509.
Griffin, M.J., Greenway, T.E., Byars, T.S., Ware, C., Aarattuthodiyil, S., Kumar, G., Wise, D.J., Waldbieser, G.C. 2020. Cross-protective potential of a live, attenuated Edwardsiella ictaluri, vaccine against Edwardsiella piscicida in channel (Ictalurus punctatus) and channel x blue (Ictalurus furcatus) hybrid catfish. Journal of the World Aquaculture Society. 51(3)740-749. https://doi.org/10.1111/jwas.12696.
Stilwell, J.M., Griffin, M.J., Rosser, T.G., Leary, J.H., Hagen-Frei, K., Pomaransk, E.K., Soto, E., Camus, A.C. 2019. First detection of erysipelothrix sp. infection in western mosquitofish gambusia affinis inhabiting catfish aquaculture ponds in Mississippi, USA. Diseases of Aquatic Organisms. 133:39-46. https://doi.org/10.3354/dao03332.
Stilwell, J.M., Camus, A.C., Leary, J.H., Mohammed, H.H., Griffin, M.J. 2019. Molecular confirmation of Henneguya adiposa and associated histologic changes in adipose fins of channel catfish, Ictalurus punctatus. Parasitology Research. 118 1639-2019. https://doi.org/10.1007/s00436-019-06295-w.
Stilwell, J.M., Rosser, T.G., Woodyard, E.T., Richardson, B.M., Lopez-Porras, A., Leary, J.H., Mischke, C.C., Camus, A.C., Griffin, M.J. 2021. Characterisation of myxozoan fauna of western mosquitofish, Gambusia affinis (Baird and Gerard 1853) (Cyprinodontiformes: Poeciliidae), inhabiting experimental catfish ponds in Mississippi, USA. Systematic Parasitology. 98 423-441. https://doi.org/10.1007/s11230-021-09987-z.
Stilwell, J.M., Griffin, M.J., Leary, J.H., Khoo, L.H., Camus, A.C. 2024. Massive branchial henneguyosis of catfish: A distinct, myxozoan-induced gill disease caused by severe interlamellar Henneguya exilis infection in catfish aquaculture. Veterinary Pathology. 61(6)965-972. https://doi.org/10.1177/03009858241259181.
Stilwell, J.M., Griffin, M.J., Rosser, T.G., Mohammed, H.H., Sidor, I.F., Camus, A.C. 2020. Insights into myxozoan composition and physiology revealed by histochemical properties of myxospores. Journal of Fish Diseases. 43(5)583-597. https://doi.org/10.1111/jfd.13152.
Gunn, M.A., Allen, P.J., Rosser, G.T., Wise, D.J., Griffin, M.J. 2021. Comparative Mortality of Juvenile Channel and Hybrid Catfish Exposed to Bolbophorus damnificus Cercariae. North American Journal of Aquaculture. 83(4)346-353. https://doi.org/10.1002/naaq.10202.
Sayed, M., Griffin, M., Ware, C., Ozdemir, O., Tekedar, H.C., Essa, M., Karsi, A., Lawrence, M.L., Abdelhamed, H. 2022. Evaluation of Edwardsiella piscicida basS and basR mutants as vaccine candidates in catfish against edwardsiellosis. Journal of Fish Diseases. 45(12)1817-1829. https://doi.org/10.1111/jfd.13703.
Aarattuthodiyil, S., Griffin, M.J., Greenway, T.E., Khoo, L.H., Byars, T.S., Lewis, M., Steadman, J., Wise, D.J. 2020. An orally delivered, live-attenuated Edwardsiella ictaluri vaccine efficiently protects channel catfish fingerlings against multiple Edwardsiella ictaluri field isolates. Journal of the World Aquaculture Society. 51(6)1354-1372. https://doi.org/10.1111/jwas.12693.
Stilwell, J.M., Camus, A.C., Woodyard, E.T., Ware, C., Rosser, T.G., Gunn, M.A., Lopez-Porras, A., Khoo, L.H., Wise, D.J., Griffin, M.J. 2023. Species-specific in situ hybridization confirms arrested development of Henneguya ictaluri in hybrid catfish (Channel Catfish × Blue Catfish) under experimental conditions, with notes on mixed-species infections in.... Journal of Aquatic Animal Health. 35(4)223-237. , https://doi.org/10.1002/aah.10196.
Shahin, K., Mukkatira, K., Yazdi, Z., Richey, C., Kwak, K., Heckman, T., Mohammed, H.H., Ortega, C., Avendaño-Herrera, R., Keleher, B., Hyatt, M.W., Drennan, J.D., Adkison, M., Griffi9n, M.J., Soto, E. 2022. Development of a quantitative polymerase chain reaction assay for detection of the aetiological agents of piscine lactococcosis. Journal of Fish Diseases. 45(6)847-859. https://doi.org/10.1111/jfd.13610.