Bacterial coldwater disease (BCWD), caused by flavobacterium psychrophilum (FP), generates substantial losses in US-farmed trout and salmon

The Department of Agriculture National Institute of Food and Agriculture awarded Michigan State University $304,356 on September 15, 2026, under the Regional Aquaculture Center Program (CFDA 10.271) to develop prevention and control strategies for bacterial coldwater disease in U.S. farmed trout and salmon.

The research addresses Flavobacterium psychrophilum (FP), the causative agent of bacterial coldwater disease, which generates substantial losses in commercial aquaculture operations. The project will develop FP serotype determination schemes, antigenically compare genetically defined FP serotypes, evaluate cross-protective efficacy of new killed FP vaccine preparations, and build awareness among producers, fish health professionals, and veterinarians regarding flavobacterial diseases and vaccination benefits. Deliverables include FP serotype determination tools, elucidation of antigenic relationships among FP serotypes, guidance for BCWD vaccine formulations, reduction in antibiotic usage, and enhanced awareness of flavobacterial diseases and vaccination approaches. The period of performance runs from September 15, 2026, through September 14, 2028, with work performed in East Lansing, Michigan. Under the Regional Aquaculture Center Program, indirect costs and tuition remission are not allowable.

Prevention and control of BCWD is challenging due to complex FP transmission routes and limited FDA-approved treatments. Moreover, US-licensed vaccines are unavailable. Our recent and ongoing USDA-funded research suggests that vast intraspecific FP antigenic variation is likely a crucial consideration for effective BCWD vaccine development. Thus, the overarching goal of the proposed research is to reduce BCWD-associated losses in US farmed trout and salmon by better understanding the antigenic variation of US FP and using that knowledge to guide and evaluate the formulation of cross-protective and immediately deployable killed vaccines against FP. Thus, we propose to: 1) develop simple and straightforward schemes for FP serotype determination; 2) antigenically compare genetically defined FP serotypes; 3) evaluate cross-protective efficacy of new killed FP vaccine preparations; and 4) build awareness among producers, fish health professionals, and veterinarians on flavobacterial diseases and the benefits of vaccination for enhancing fish health. This research will improve BCWD prevention in the short-medium term by developing FP serotype determination tools, elucidating antigenic relationships amongst FP serotypes, guiding BCWD vaccine formulations, reducing antibiotic usage, and improving awareness of flavobacterial diseases and vaccination approaches. This proposal addresses the critical disease issues impacting commercial aquaculture species and maximizing farmer profit through novel technologies...and/or more effective management strategies for commercial aquaculture species priorities of the USDA-nifa special research grants program, and the increasing profitability of farmers and ranchers priority of the USDA secretary's memorandum 1078-020.