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Diseases of Aquatic Organisms

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DAO 145:21-33 (2021)  -  DOI: https://doi.org/10.3354/dao03598

Sea star wasting disease pathology in Pisaster ochraceus shows a basal-to-surface process affecting color phenotypes differently

Thierry M. Work1,*, Tina M. Weatherby2, Christopher M. DeRito3, Ryan M. Besemer3,4, Ian Hewson3

1US Geological Survey, National Wildlife Health Center, Honolulu Field Station, Honolulu, HI 96850, USA
2University of Hawaii, Pacific Biosciences Research Center, Biological Electron Microscope Facility, Honolulu, HI 96822, USA
3Cornell University, Department of Microbiology, Ithaca, NY 14853, USA
4University of North Carolina, Wilmington, NC 28403, USA
*Corresponding author:

ABSTRACT: Sea star wasting disease (SSWD) refers to a suite of poorly described non-specific clinical signs including abnormal posture, epidermal ulceration, and limb autotomy (sloughing) causing mortalities of over 20 species of sea stars and subsequent ecological shifts throughout the northeastern Pacific. While SSWD is widely assumed to be infectious, with environmental conditions facilitating disease progression, few data exist on cellular changes associated with the disease. This is unfortunate, because such observations could inform mechanisms of disease pathogenesis and host susceptibility. Here, we replicated SSWD by exposing captive Pisaster ochraceus to a suite of non-infectious organic substances and show that development of gross lesions is a basal-to-surface process involving inflammation (e.g. infiltration of coelomocytes) of ossicles and mutable collagenous tissue, leading to epidermal ulceration. Affected sea stars also manifest increases in a heretofore undocumented coelomocyte type, spindle cells, that might be a useful marker of inflammation in this species. Finally, compared to purple morphs, orange P. ochraceus developed more severe lesions but survived longer. Longer-lived, and presumably more visible, severely-lesioned orange sea stars could have important demographic implications in terms of detectability of lesioned animals in the wild and measures of apparent prevalence of disease.


KEY WORDS: Echinoderm · Clinical pathology · Histopathology · Light microscopy · Electron microscopy


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Cite this article as: Work TM, Weatherby TM, DeRito CM, Besemer RM, Hewson I (2021) Sea star wasting disease pathology in Pisaster ochraceus shows a basal-to-surface process affecting color phenotypes differently. Dis Aquat Org 145:21-33. https://doi.org/10.3354/dao03598

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