Ciliate parasites and related diseases of crustacea: A review

Abstract

Abstract The phylum Ciliophora is composed of a large number (>7000; Sleigh, 1989) of organisms characterized by the possession of two key features: nuclear dualism and an infraciliature. These two characteristics and the ability of ciliates to exploit their environment have resulted in a taxon composed of organisms with extreme morphological diversity. Macroorganisms, as well as other microorganisms that share the same environment, will likely be impacted by members of this taxon. The external surfaces of Crustacea provide for a wide array of microenvironments that attract the settlement and growth of algae, bacteria, fungi, and numerous types of protists, including sessile (e.g., cyrtophorids) and sedentary ciliates (e.g., chonotrichs, suctorians, some peritrichs). This “forest”; in turn attracts ciliates with predatory or browsing feeding tendencies (e.g., pleurostomes). Other ciliates have evolved to exploit the temporary presence of host body fluids released or lost during molting (e.g., apostomes). Still other ciliates actively invade crustacean tissues (e.g., other apostomes) or enter through wounds in the exoskeleton (e.g., philasterine scuticociliates). This article reviews the status of ciliate/crustacean relationships by presenting information on the prevalence and distribution of ciliates on crustaceans and the effects that ciliates may have on their hosts.