Fish Immune Responses to Myxozoa

Myxozoans evoke important economic losses in aquaculture production,
but there is almost a total lack of disease control methods as no vaccines or
commercial treatments are currently available. Knowledge of the immune
responses that lead to myxozoan elimination and subsequent disease
resistance is vital for shaping the future development of disease control
measures. Different fish immune factors triggered by myxozoan parasites
are reviewed in this chapter. Detailed information on the phenotypic and
underlying molecular aspects of innate and adaptive responses, at both
cellular and humoral levels, is provided for some well-studied fishmyxozoan
systems. The importance of the local immune response, mainly
at mucosal sites, is also highlighted. Myxozoan tactics to disable or avoid
immune responses, such as modulation of immune gene transcription and
immune evasion, are also reviewed. The existence of innate and acquired
resistance to some myxozoan species suggest promising possibilities for
controlling myxozooses through immune-based strategies, such as genetic
selection for host resistance, vaccination, immune therapies and administration
of immunostimulants.