A review of bacterial co-infections in farmed catfish: Components, diagnostics, and treatment directions

Authors: WISE, ALLISON - Auburn University; Lafrentz, Benjamin; KELLY, ANITA - Auburn University; KHOO, LESTER - Mississippi State University; XU, TINGBI - Auburn University; LILES, MARK - Auburn University; BRUCE, TIMOTHY - Auburn University

Submitted to: Animals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2021
Publication Date: 11/12/2021
Citation: Wise, A.L., Lafrentz, B.R., Kelly, A.M., Khoo, L., Xu, T., Liles, M.R., Bruce, T.J. 2021. A review of bacterial co-infections in farmed catfish: Components, diagnostics, and treatment directions. Animals. 11:3240. https://doi.org/10.3390/ani11113240.
DOI: https://doi.org/10.3390/ani11113240

Interpretive Summary: The largest sector of food fish production in the United States is catfish. Disease outbreaks that occur during production account for substantial economic losses and there is a need for improved disease prevention methods to sustain the industry. Several bacterial pathogens, such as Edwardsiella spp., Aeromonas spp., and Flavobacterium columnare are the leading causes of these losses. While each of these pathogens can cause disease alone, many times disease outbreaks in the industry are due to co-infections, in which more than one pathogen is involved. Co-infections can complicate diagnosis of the disease, increase mortality, and make disease management more difficult. Although co-infections are common, there is a gap in knowledge of the effects of bacterial-bacterial co-infections in catfish aquaculture. A thorough understanding of these will allow for the development of improved prevention and control methods. This review provides an overview of co-infections in catfish aquaculture, diagnostic case data from Mississippi and Alabama, and future research initiatives that are needed to decrease the impact of co-infections.

Technical Abstract: Catfish production is a major aquaculture industry in the United States and is the largest sector of food fish production. As producers aim to optimize production yields, diseases caused by bacterial pathogens are responsible for high pond mortality rates and economic losses. The major bacterial pathogens responsible are Edwardsiella ictaluri, Aeromonas spp., and Flavobacterium columnare. Given the outdoor pond culture environments and ubiquitous nature of these aquatic pathogens, there have been many reports of co-infective bacterial infections within this aquaculture sector. Co-infections may be responsible for altering disease infection mechanics, increasing mortality rates, and creating difficulties for disease management plans. Further, proper diagnoses of primary and secondary pathogens are essential in ensuring the correct treatment approaches for antimicrobials and chemical applications. A thorough understanding of the interactions and infectivity dynamics for these warmwater bacterial pathogens will allow for the adoption of new prevention and control methods, particularly in vaccine development. This review aims to provide an overview of co-infective pathogens in catfish culture and present diagnostic case data from Mississippi and Alabama to define prevalence for these multiple-species infections better.