Members of the
genus Kudoa primarily infect
muscle tissue of marine fishes, where they form nodules or pseudocysts containing a great number of individual spores. In lighter infections these pseudocysts are isolated from the fish's
immune system within the muscle fibre. More intense infections can result in severe
inflammation surrounding infected muscle fibres. Although apparently asymptomatic in all but heavy infections, they are associated with post-mortem degeneration of the tissue. This softening of flesh is most likely a result the release of
proteolytic enzymes by the parasite. This causes losses to both
aquaculture operations, for instance, where
salmon are being reared in "sea-pens", and to
capture fisheries. Losses are both direct, through the degradation of fish products, and indirectly, through the perception of the
consumer that fish from a particular area are of a lower quality. The intensity of
K. thyrsites infection is
positively correlated with the severity of flesh softening in Atlantic salmon fillets. Softening of flesh always occurred with heavily infected fillets, while lightly infected fillets showed no softening. Prevention and/or control of
K. thyrsites infections is problematic especially in open water netpens. Currently there are no available treatments. One approach to control may be to disrupt the life cycle in some way thereby minimizing the likelihood of infection. ==Life cycle==