Clinical Pathology, Serum Brevetoxin, and Clinical Signs of Florida Manatees (Trichechus manatus latirostris) During the Brevetoxin-Related Mortality Event in Southwest Florida 2013
American Association of Zoo Veterinarians Conference 2014
Ray Ball1, DVM; Catherine J. Walsh2, PhD; Leanne Flewelling3, PhD; Elizabeth Arnett4; Lauren Smith4; Ashley Barratclough1,4, BVetMed, MSc; Trevor J. Gerlach1, DVM
1Veterinary Sciences, Tampa’s Lowry Park Zoo, Tampa, FL, USA; 2Marine Immunology Program, Mote Marine Laboratory, Sarasota, FL, USA; 3Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL, USA; 4Aquatic Animal Health Division, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
During a red tide-associated mass mortality event in southwest Florida in the winter and spring of 2012–2013, 16 manatees were rescued and presented to Tampa’s Lowry Park Zoo (TLPZ). All manatees were examined, had blood samples taken for routine complete blood cell counts (CBC), serum biochemistry panels, and coagulation profiles (prothrombin time, partial thromboplastin time, fibrinogen concentration, platelet counts, and D-dimer concentration). Serum or plasma was banked for brevetoxin analysis, and whole blood was collected in heparinized blood tubes for lymphocyte transformation (LTT) assays when possible. Brevetoxin analysis and LTT were repeated as possible during the convalescent period as well as at pre-release health assessments. Fifteen manatees were given atropine: 0.02 mg/kg with ¼ the dose given IV and the remaining ¾ SQ. All manatees were given a course of injectable tulathromycin at 2.5 mg/kg SQ q 7 d for 3 treatments and were fitted with flotation devices. Time to the removal of the flotation gear was recorded. Fifteen manatees survived and were released. Statistical clinical pathology differences between brevetoxin-exposed manatees and the control population included inflammatory and stress responses, bleeding tendencies, and lower electrolyte levels in the brevetoxin-exposed group. Recovery time for conscious manatees was half that of unconscious manatees. Serum brevetoxin levels (PbTx3, ng/ml) were not different between conscious and unconscious manatees, but all manatees measured tended to have serum brevetoxin levels decrease during the first several weeks of rehabilitation. Lymphocyte transformation shows suppression, but the clinical significance of this is still not understood.
The authors wish to thank Dr. Nico Maldonado; the Veterinary Clinic Staff of Heather Henry, CVT and Michelle Devlin, CVT, and the Manatee Rehabilitation Team led by Virginia Edmonds from Tampa’s Lowry Park Zoo. In addition, we would like to gratefully acknowledge USFWC and FWC, in particular Martine de Wit, Andy Garrett, Denise Boyd, and everyone at the Marine Mammal Pathobiology Lab for their assistance.