Gross and microscopic morphology of lesions in Cnidaria from Palmyra Atoll, Central Pacific

Journal of Invertebrate Pathology
By: , and 

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Abstract

We conducted gross and microscopic characterizations of lesions in Cnidaria from Palmyra Atoll, Central Pacific. We found growth anomalies (GA) to be the most commonly encountered lesion. Cases of discoloration and tissue loss were rare. GAs had a focal or multi-focal distribution and were predominantly nodular, exophytic, and umbonate. In scleractinians, the majority of GAs manifested as hyperplasia of the basal body wall (52% of cases), with an associated absence or reduction of polyp structure (mesenteries and filaments, actinopharynx and tentacles), and depletion of zooxanthellae in the gastrodermis of the upper body wall. In the soft corals Sinularia sp. and Lobophytum sp., GAs exclusively manifested as prominent hyperplasia of the coenenchyme with an increased density of solenia. In contrast to scleractinians, soft coral GAs displayed an inflammatory and necrotizing component with marked edema of the mesoglea, accompanied by infiltrates of variably-sized granular amoebocytes. Fungi, algae, sponges, and Crustacea were present in some scleractinian GAs, but absent in soft coral GAs. Fragmentation of tissues was a common finding in Acropora acuminata and Montipora cf. dilatata colonies with tissue loss, although no obvious causative agents were seen. Discoloration in the zoanthid, Palythoa tuberculosa, was found to be the result of necrosis, while in Lobophytum sp. discoloration was the result of zooxanthellar depletion (bleaching). Soft corals with discoloration or tissue loss showed a marked inflammatory response, however no obvious causative organisms were seen. Lesions that appeared similar at the gross level were revealed to be distinct by microscopy, emphasizing the importance of histopathology.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Gross and microscopic morphology of lesions in Cnidaria from Palmyra Atoll, Central Pacific
Series title Journal of Invertebrate Pathology
DOI 10.1016/j.jip.2010.08.002
Volume 106
Issue 2
Year Published 2011
Language English
Publisher Elsevier
Contributing office(s) National Wildlife Health Center
Description 9 p.
First page 165
Last page 173
Other Geospatial Palmyra Atoll
Online Only (Y/N) N
Additional Online Files (Y/N) N