Diseases of Echinodermata. II. Agents metazoans (Mesozoa to Bryozoa)

Abstract

The only species of Mesozoa known to parasitize echinoderms is clearly pathogenic; it causes the regression of ovaries of infested ophiuroids. Symbiotic turbellarians have been reported for each echinoderm group; they mainly infest the gut and coelom of aspidochirote holothuroids and regular echinoids. Echinoderms generally act as second intermediary host for trematodes; the latter are known mostly from echlnoids and ophiuroids which constitute the most frequent echinoderm prey for fishes. Records of echmodem-infeslng nematodes are rather scarce; they usually infest either the coelom or the gonads of their host. Many eulimid gastropods have been reported to parasitize echinoderms; however, most of them do not seem to seriously alter the echinoderm life cycle. They are no bivalves parasitic on echinodems except a few species inhabiting the gut of holothuroids. Associations between echinoderms and sponges, cnidarians, entoprocts or bryozoans have been casually reported in the literature.