Identifying coagulopathies in the pathophysiology of cold stress syndrome in the Florida manatee Trichechus manatus latirostris

DEVELOPING A THROMBOELASTOGRAPHY ASSAY IN ELASMOBRANCHS

Thromboelastography (TEG) is a hemostatic assay evaluating clot initiation time, kinetics, strength, and extent of fibrinolysis. Hemostatic assays in nonmammalian species have been less extensively studied because of lack of taxon-specific reagents and unique physiology. Hemostatic or hemorrhagic disease has been described postmortem in elasmobranchs, but antemortem detection of coagulopathies is limited in this taxon. The study aimed to establish an elasmobranch TEG protocol to improve hemostatic evaluation and facilitate advanced treatment options for animals under human care. Multiple clotting initiators were assessed for efficacy with frozen-thawed citrated plasma, fresh citrated plasma, and fresh whole citrated blood: RapidTEGTM, citrated kaolin, Reptilase®, and species brain-derived thromboplastin prepared by two different methods. Initial evaluation found plasma samples clot inconsistently, but TEG analyses using fresh whole blood consistently led to measurable TEG reactions using multiple clotting initiators. The most reliable elasmobranch TEG results were observed using citrated fresh whole blood and the RapidTEG clot initiation reagent.

Persistent long-term habitat use by Florida manatees at Fort Pierce, Florida from 1997 to 2020

To survive cold winters, Florida manatees (Trichechus manatus latirostris) depend on artificial (i.e., power plants) and natural warm water sources such as springs and passive thermal basins. Passive thermal basins can provide critical habitat for manatees for short or extended periods of time. The Henry D. King Powerplant in Fort Pierce, Florida discharged warm water into Moore's Creek until it went offline in 1995. However, it is unknown to what degree manatees continue to occupy this area and how environmental factors influence their occurrence in the creek. To explore this, we examined the habitat use of Florida manatees in Moore's Creek after the shutdown from November 1997 to March 2020 from daily counts of manatees. In addition, we correlated local environmental data (ambient air, temperature, salinity) to assess if Moore's Creek had properties indicative of a passive thermal basin. Results indicated there was not an increase or decrease in habitat use over twenty years in the Creek. The consistent use of Moore's Creek over the study period suggests that this habitat possesses thermal and freshwater resources to support manatee occurrence long-term. These findings provide robust support for the importance of this habitat and passive thermal basins for Florida manatees.

Viscoelastic Coagulation Testing in Exotic Animals

Whole blood viscoelastic coagulation testing (VCT) allows global assessment of hemostasis and fibrinolysis. Although not widely used in exotic animal practice, VCT has been used in exotic animal research settings. Differences in patient demographics and analytical variables can result in dramatically different results with the same analyzer. To improve the utility of VCT in exotic animal medicine, standardization of protocols is necessary to facilitate the establishment of reference intervals. Despite these challenges, the quantitative/qualitative nature of VCT has already proved its real-world value to some clinicians.

Clinicopathological prognostic indicators of survival and pathological findings in cold-stressed Florida manatees Trichechus manatus latirostris

Cold-stress syndrome (CSS) is a leading natural cause of mortality in free-ranging Florida manatees Trichechus manatus latirostris, but comprehensive investigations into blood analyte derangements and prognostic indicators in CSS are lacking. The objectives of this study were to (1) compare admission blood analyte data of manatees pre and post rehabilitation for CSS to identify clinicopathological derangements, (2) identify blood analyte prognostic indicators for survival, and (3) correlate post-mortem anatomic pathological changes with clinicopathological findings to improve the understanding of CS pathophysiology. CSS manatees admitted to a rehabilitation facility between 2007 and 2017 were included: 59 manatees with data for clinicopathological analysis (7 non-survivors and 49 survivors) and 14 manatees with necropsy data (7 with and 7 without blood analyte data). Main interpretive clinicopathological findings indicated systemic inflammation, bone marrow damage, diuresis, malnutrition, tissue necrosis, fat mobilization, hepatic impairment, acid-base imbalances, and gastrointestinal ulceration. The best diagnostically performing prognostic indicators for survival included platelet concentration, aspartate aminotransferase, calcium, and blood urea nitrogen. The main anatomic pathological findings were cutaneous lesions (n = 14), lipid depletion (n = 12), upper gastrointestinal ulceration and/or hemorrhage (n = 9), and pneumonia (n = 5). Based on the identified blood prognostic indicators interpreted in the context of anatomic pathological findings, multi-organ tissue injury, gastrointestinal ulceration and/or hemorrhage, and hemodynamic and platelet derangements are the presumptive major factors of CSS manatee mortality. These results contribute to the understanding of the complex CSS pathophysiology and offer the use of blood analyte prognostic indicators as a clinically applicable tool for the medical care of manatees during rehabilitation, thereby contributing to increased rehabilitation success and conservation of the Florida manatee.

Thromboelastography in wild Florida manatees (Trichechus manatus latirostris)

BACKGROUND

Thromboelastography (TEG) provides a comprehensive evaluation of blood clot formation. This test can be used to identify abnormalities in coagulation by assessing multiple aspects of the clotting cascade, including the speed of clot initiation and formation, clot strength, and ultimately fibrinolysis. Thromboembolic disease has been hypothesized to play a role in the pathophysiology of cold stress syndrome (CSS), an important cause of mortality in the threatened Florida manatee (Trichechus manatus latirostris).

OBJECTIVES

The objective of this study was to establish thromboelastography RIs using the TEG 5000 with citrated whole blood samples and kaolin activation in wild, healthy manatees.

METHODS

In December 2014 and January 2015, 29 wild manatees (17 male and 12 female) were blood sampled as part of the annual wild manatee health assessments organized by United States Geological Survey (USGS). TEG was performed using citrated kaolin-activated samples.

RESULTS

The samples were obtained from manatees caught in Crystal River, Citrus County, and used to identify the mean ± SD of normal TEG parameters: R = reaction time 2.1 minutes (0.8), K = clot formation time 0.8 min (0), α angle = 83.1° (2), MA = maximum amplitude 75 mm (7.6), and LY30 = clot lysis 0.41% (0.68). No significant differences were found between manatee size, sex, or time between sampling and running the test.

CONCLUSIONS

Manatee TEG parameters demonstrate a relatively hypercoagulable condition when compared to other mammals. This information will facilitate detection of changes in hemostasis during injury and disease and provide a valuable reference range.