In conclusion, shell disease is not a disease caused by a single pathogen and should not be considered a disease solely restricted to the exoskeleton. Numerous bacteria within the marine environment are capable of degradation of the chitin component of the crustacean cuticle and it is likely that the collective effects of the lesion community lead to further exoskeletal degradation. If breach of the cuticle occurs, infection of the body cavity of the crustacean may result, with the internal symptoms differing depending on the nature of the penetrating bacteria and this may ultimately lead to the death of the animal.