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Detection of the Diadema antillarum scuticociliatosis Philaster clade on sympatric metazoa, plankton, and abiotic surfaces and assessment for its potential reemergence

January 30, 2025

A ciliate belonging to the Diadema antillarum scuticociliatosis (DaSc)-associated Philaster clade (DaScPc) caused catastrophic long-spined urchin mass mortality in spring and summer of 2022. The ciliate can be grown in culture in both the presence and absence of D. antillarum tissues, suggesting that it may persist outside its host by consuming microorganisms or dissolved organic nutrients. We hypothesized that DaScPc was present outside its host during and after mass mortality and absent prior to 2022. We examined DaScPc in DNA extracted from 500 swabs of sym- patric metazoa and abiotic surfaces, and plankton samples, collected at 35 sites in the Caribbean in 2022 and 2023. DaScPc was detected on corals, turf algae, and a sponge, predominantly at sites with active or prior DaSc. We examined whether it was present prior to 2022 by surveying extracted DNA from Caribbean corals and water collected near corals by PCR and by mining publicly available transcriptomes and metagenomes for DaScPc rRNAs. These efforts yielded no DaScPc genes. We further hypothesized that DaScPc may recruit to the specific corals detected in field surveys, and that these may then infect naïve hosts. A mesocosm experiment to test DaScPc recruitment suggested that, while it recruited to corals, it did so inconsistently between coral species. Incubation of corals that recruited DaScPc with naïve urchins yielded inconclusive results since urchins died without characteristic DaSc signs. Overall, our results suggest that DaScPc may occur outside its urchin host, and that it may have been absent in the region prior to 2022.

Publication Year 2025
Title Detection of the Diadema antillarum scuticociliatosis Philaster clade on sympatric metazoa, plankton, and abiotic surfaces and assessment for its potential reemergence
DOI 10.3354/meps14763
Authors Brayan Vilanova-Cuevas, Katherine Philipp, Ashley Altera, Amy Apprill, Cynthia C. Becker, Donald Behringer, Marilyn E. Brandt, Mya Breitbart, Kayla A. Budd, Christopher M. DeRito, Elizabeth Duermit-Moreau, James S. Evans, Maria Hopson-Fernandes, Julian Fleischer, Samuel Gittens Jr., Michael Henson, Alwin Hylkema, Christina A. Kellogg, Andrew Maritan, Julie L. Meyer, Zoe A. Pratte, Isabella T. Ritchie, Moriah L.B. Sevier, Matthew Souza, Frank J. Stewart, Sietske Van Der Wal, Sarah VonHoehne, Ian Hewson
Publication Type Article
Publication Subtype Journal Article
Series Title Marine Ecology Progress Series
Index ID 70263202
Record Source USGS Publications Warehouse
USGS Organization St. Petersburg Coastal and Marine Science Center
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