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

June 3, 2021

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.

Publication Year 2021
Title Sea star wasting disease pathology in Pisaster ochraceus shows a basal-to-surface process affecting color phenotypes differently
DOI 10.3354/dao03598
Authors Thierry M. Work, Tina M. Weatherby, Christopher M. DeRito, Ryan M. Besemer, Ian Hewson
Publication Type Article
Publication Subtype Journal Article
Series Title Diseases of Aquatic Organisms
Index ID 70221792
Record Source USGS Publications Warehouse
USGS Organization National Wildlife Health Center