Brevetoxicosis in Florida manatees (Trichechus manatus latirostris): Plasma proteomics for Florida red tide biomarkers.

Florida manatees face recurring exposure to brevetoxins, a suite of neurotoxins produced by the dinoflagellate Karenia brevis, through inhalation and forage. Near annual blooms in the Gulf of Mexico lead to repeated epizootics and mass strandings. Although stranded manatees are often rescued and receive palliative care, plasma biomarkers for health surveillance and diagnostic decision making remain limited. To investigate mechanisms and identify biomarkers, we applied TMT plasma proteomics comparing exposed and unexposed manatees. The relative abundances of multiple manatee plasma proteins, especially those related to cell adhesion and the immune system, were significantly altered in the red tide exposed compared to healthy free-ranging manatees. Potential biomarkers, identified by proteomic analysis, were validated, including periostin, overall protease inhibition, and plasma copper, consistent with higher ceruloplasmin inferred from proteomics. Given the increasing severity and duration of red tide blooms due to climate change, the threatened status of manatees, and the observed plasma protein changes following exposure, this study is critical for improving diagnosis and developing mechanism-based treatments for brevetoxicosis in manatees.