Location: Aquatic Animal Health Research
Project Number: 6010-32000-027-018-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2021
End Date: Aug 30, 2026
While single pathogens are routinely reported in diagnostic cases, coinfections with multiple pathogens are very common and poorly understood. Recent diagnostic reports in Mississippi and Alabama (2017-2020) reveal a staggering number of fish health cases involving coinfections, approaching nearly 35% of all diagnostic cases, which are widely thought by industry professionals to be underreported. These infections are known to alter fish health and performance and minimize the effectiveness of currently used control and prevention strategies. There is a need to better understand and characterize these pathogen interactions and discern both the mechanisms for pathogenicity and the immunological responses in catfish. The objectives of the proposed project are: 1) determine mechanisms of virulence relating to coinfections within an array of industry-important catfish pathogens, including Flavobacterium columnare, virulent Aeromonas spp., Edwardsiella spp., and channel catfish virus (CCV); 2) characterize the fish immune response during coinfections; and 3) evaluate both directed and potentially cross-protective vaccines and therapeutants against these complex infections.
In collaboration, USDA-ARS and AU will conduct industry-relevant research that will provide an understanding of coinfections in warmwater aquaculture and develop preventative and/or therapeutic measures and assess mechanics involving pathogen coinfections. This applied research will enhance the health of production stocks and contribute to securing domestic food production through sustainable means. The team will conduct a series of wet laboratory challenge trials, define catfish immune responses to mixed infections, and look at the use of vaccines and therapeutants to mitigate these complex diseases. The studies will involve the use of in vivo challenge trials, as well as in vitro bench assays to discern mechanisms involved and assess virulence of co-infective bacterial pathogens.