Mucosal vaccination of fish

Among the novel vaccination methods, mucosal vaccination seems to possess all the desired criteria. The chapter reviews the state-of-the-art knowledge regarding this type of vaccination with a focus on their uptake, immune stimulation, and where possible, discusses their potential as future vaccines. It also discusses the reasons why it is not yet extensively used. Information on the mucosal immune system, suitable mucosal antigens and adjuvants and uptake mechanisms are also included. The chapter summarizes a variety of methods that are employed to deliver antigen safely to the hindgut, induce local or systemic immune responses, and, most importantly, induce immunological memory and achieve long-term protection. Immersion vaccination may be more effective when combined with ultrasound or other controlled skin or gill damage. Finally, the chapter pays attention to species-specific differences in mucosal anatomy and function in prominent farmed fish species.