Eosinophilia and biotoxin exposure in bottlenose dolphins (Tursiops truncatus) from a coastal area impacted by repeated mortality events
- National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Road, Charleston, SC 29412 (United States)
- University of Connecticut, Department of Pathobiology and Veterinary Science, 61 North Eagleville Road, U-89, Storrs, CT 06269 (United States)
- Chicago Zoological Society, c/o Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States)
- Bayside Hospital for Animals, 251 N.E. Racetrack Road, Fort Walton Beach, FL 32547 (United States)
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, Marine Mammal Health and Stranding Response Program, 1315 East West Highway, Silver Spring, MD 20910 (United States)
- Ocean Embassy Inc, 6433 Pinecastle Blvd, Ste 2, Orlando, FL 32809 (United States)
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service Southeast Fisheries Science Center,101 Pivers Island Road, Beaufort, NC 28516 (United States)
Bottlenose dolphins (Tursiops truncatus) inhabiting coastal waters in the northern Gulf of Mexico have been impacted by recurrent unusual mortality events over the past few decades. Several of these mortality events along the Florida panhandle have been tentatively attributed to poisoning from brevetoxin produced by the dinoflagellate Karenia brevis. While dolphins in other regions of the Florida coast are often exposed to K. brevis blooms, large-scale dolphin mortality events are relatively rare and the frequency and magnitude of die-offs along the Panhandle raise concern for the apparent vulnerability of dolphins in this region. We report results from dolphin health assessments conducted near St. Joseph Bay, Florida, an area impacted by 3 unusual die-offs within a 7-year time span. An eosinophilia syndrome, manifested as an elevated blood eosinophil count without obvious cause, was observed in 23% of sampled dolphins. Elevated eosinophil counts were associated with decreased T-lymphocyte proliferation and increased neutrophil phagocytosis. In addition, indication of chronic low-level exposure to another algal toxin, domoic acid produced by the diatom Pseudo-nitzschia spp., was determined. Previous studies of other marine mammal populations exposed recurrently to Pseudo-nitzschia blooms have suggested a possible link between the eosinophilia and domoic acid exposure. While the chronic eosinophilia syndrome could over the long-term produce organ damage and alter immunological status and thereby increase vulnerability to other challenges, the significance of the high prevalence of the syndrome to the observed mortality events in the St. Joseph Bay area is unclear. Nonetheless, the unusual immunological findings and concurrent evidence of domoic acid exposure in this sentinel marine species suggest a need for further investigation to elucidate potential links between chronic, low-level exposure to algal toxins and immune health.
- OSTI ID:
- 22149225
- Journal Information:
- Environmental Research, Vol. 110, Issue 6; Other Information: Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0013-9351
- Country of Publication:
- United States
- Language:
- English
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