Application of Bacteriophages for Control of Infectious Diseases in Aquaculture

Abstract

Vaccination is an ideal method for prevention of infectious diseases, but commercially available vaccines are still limited in the aquaculture field. Bacteriophages (phages) as specific pathogen-killers are attractive agents for treating or controlling bacterial infections. Studies on phages of fish pathogens and aquaculture phage therapy have become more popular since the late 1990s, with an increasing interest in recent years. This chapter reviews research results and discusses the potential for controlling bacterial infections in aquaculture by means of phages. Ayu (Plecoglossus altivelis) is an osmerid fish with a 1-year life cycle and is one of the most popular freshwater species for sport fishing as well as for aquaculture in Japan. Two bacterial diseases, bacterial hemorrhagic ascites caused by Pseudomonas plecoglossicida and bacterial cold-water disease (BCWD) caused by Flavobacterium psychrophilum have damaged the aquaculture industry and the natural resource enhancement program of this fish species since 1990. Phage therapy against bacterial diseases of fish remains an inadequately studied topic, and further intensive investigations of various aspects of the practice are required to establish its practical feasibility in aquaculture. Phage therapy is both an old and an attractive new approach to prevent and control bacterial infections and potentially applicable to any field affected by bacterial infection, including aquaculture.