Abstract
Recent studies performed at Lowry Park Zoo have implicated the role of thromboembolic disease in the pathophysiology of cold stress syndrome in the Florida manatee (Trichechus manatus latirostris).1 To establish the role of coagulopathy in cold stress syndrome, we needed to establish the normal coagulation factors and parameters. As part of the ongoing manatee health assessments at Crystal River, FL, we collected additional citrated plasma blood samples and ran the following analyses: PT, PTT, fibrinogen, D-dimers and factors VII, VIII, IX, X, XI and XII. We sampled 10 animals from Crystal River and 11 animals from Brevard County, FL to establish our normal reference ranges for the wild manatee population. Thromboelastography was performed on the Crystal River samples to establish normal TEG reference ranges and a standard protocol for thromboelastography in manatees. Biochemistry and haematology of the wild manatees were confirmed to be within the normal reference ranges classifying these animals as healthy individuals.2 Previous work in the 1980s was performed on captive manatees; however, to the authors' knowledge this is the first time coagulation factors have been established in wild free-ranging manatees.
Subsequently each manatee admitted to our facility for cold stress syndrome rehabilitation was sampled for both coagulation factor analysis and thromboelastography. The results so far support our hypothesis that cold stress syndrome manatees demonstrate a hypercoagulable state. This was reflected in the thromboelastography by low R (reaction time) and K values (speed of clot formation) and an increased MA (clot strength). Our next step is to determine whether disseminated intravascular coagulopathy (DIC) is present in cold stress syndrome. This can be demonstrated via thromboelastography showing a hypercoagulable state initially followed by a hypocoagulable state. We propose that the presence of DIC can be diagnosed in manatees - as in other mammals - with a combination of three or more of the following results: prolonged PT, prolonged aPTT, D-dimer elevation, thrombocytopenia, and low fibrinogen. All cold stress manatees were sampled at the time of admission and 1 week post-admission per rehabilitation protocols; this enabled monitoring for improvement or deterioration of any coagulopathy. Additional samples are required to determine if there is a significant difference between healthy wild manatees and those suffering from cold stress syndrome; however, with the available data, the trends support the hypothesis.
Acknowledgements
The authors wish to thank Dr. Bob Bonde and the Crystal River manatee health assessment team, as well as Dr. Ruth Francis Floyd, Dr. Nicole Stacy and Dr. Roger Reep at the University of Florida. The authors would also like to thank Drs. Trevor Gerlach, Lauren Smith and Bryan Vorbach, the veterinary clinic staff Michelle Devlin and Heather Henry and the Manatee Rehabilitation Team led by Virginia Edmonds at Tampa's Lowry Park Zoo.
* Presenting author
+ Student presenter
Literature Cited
1. Ball RL. Thromboembolic disease as a component of health issues in the Florida manatee (Trichechus manatus latirostris). In: Proceedings from the IAAAM 27th Annual Conference, Sausalito, CA; 2013.
2. Harvey JW, Harr KE, Murphy D, Walsh MT, Chittick EJ, Bonde RK, Pate MG, Deutsch CJ, Edwards HH, Haubold EM. Clinical biochemistry in healthy manatees (Trichechus manatus latirostris). Journal of Zoo and Wildlife Medicine. 2007;38(2):269–279.