Establishment of reference values for various coagulation tests in healthy Florida manatees (Trichechus manatus latirostris) and evaluation of coagulation in debilitated manatees during rehabilitation

Molecular characterization of positively selected genes contributing aquatic adaptation in marine mammals

BACKGROUND

Marine mammals, which have evolved independently into three distinct lineages, share common physiological features that contribute to their adaptation to the marine environment.

OBJECTIVE

To identify positively selected genes (PSGs) for adaptation to the marine environment using available genomic data from three taxonomic orders: cetaceans, pinnipeds, and sirenians.

METHODS

Based on the genomes within each group of Artiodactyla, Carnivora and Afrotheria, we performed selection analysis using the branch-site model in CODEML.

RESULTS

Based on the branch-site model, 460, 614, and 359 PSGs were predicted for the cetaceans, pinnipeds, and sirenians, respectively. Functional enrichment analysis indicated that genes associated with hemostasis were positively selected across all lineages of marine mammals. We observed positive selection signals for the hemostasis and coagulation-related genes plasminogen activator, urokinase (PLAU), multimerin 1 (MMRN1), gamma-glutamyl carboxylase (GGCX), and platelet endothelial aggregation receptor 1 (PEAR1). Additionally, we found out that the sodium voltage-gated channel alpha subunit 9 (SCN9A), serine/arginine repetitive matrix 4 (SRRM4), and Ki-ras-induced actin-interacting protein (KRAP) are under positive selection pressure and are associated with cognition, neurite outgrowth, and IP3-mediated Ca2 + release, respectively.

CONCLUSION

This study will contribute to our understanding of the adaptive evolution of marine mammals by providing information on a group of candidate genes that are predicted to influence adaptation to aquatic environments, as well as their functional characteristics.

Trends of the Florida manatee (Trichechus manatus latirostris) rehabilitation admissions 1991-2017

A retrospective study of admission data of 401 West Indian manatees (Trichechus manatus latirostris) presented to the David A. Straz Jr. Manatee Critical Care Center at ZooTampa at Lowry Park (ZooTampa) for rehabilitation from August 1991 through October 2017. Causes of admittance, location of rescue, gender, and age class were all recorded for each manatee admitted. Admittance categories as defined by the Florida Fish and Wildlife Conservation Commission (FWC) included watercraft collisions, natural causes, entanglement, entrapment, orphaned calves, captive born, mothers of rescued calves, calves of rescued mothers, human, and other. The admitted population was primarily from the southwest and northwest coasts and related waterways of Florida. The gender difference was relatively equivocal (54% female) while the adults comprised 79% of the admissions. The overall total admissions increased steadily over the study period as did the admissions for each individual categories of admission. Watercraft collisions and natural causes combined were 71% of all admissions for the entire study period and are the dominant causes of admission. Watercraft collisions are more likely to occur during May through October, whereas natural causes of admittance are more likely to occur between December and March. Rehabilitated manatees may reduce overall manatee mortality and can provide insight into population-based health concerns if evaluated appropriately. Future efforts can incorporate physical examination findings, hematology, biochemistry profiles, and ancillary diagnostic testing to continue to improve the individual welfare of this marine mammal in its natural range. Admissions data could also potentially serve the wider conservation and recovery efforts if it is proven that the data obtained is at least as informative as that obtained by the carcass salvage program. Limited conservation resources could then be re-directed as new challenges arise with the expanding population and potentially expanding range of this species.

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.

COAGULATION ASSESSMENT: UNDERUTILIZED DIAGNOSTIC TOOLS IN ZOO AND AQUATIC ANIMAL MEDICINE

Veterinarians specializing in nondomestic species are faced with unique challenges regarding research and diagnostic capabilities given the wild and frequently dangerous nature of their patients. Standard diagnostic techniques used in small or large animal practice are not always possible due to anatomical constraints, size, tractability, or the inherent risk of anesthesia in highly valued, rare species. Diagnostic modalities that utilize simple, relatively noninvasive techniques show promise in evaluating nondomestic species and elucidating the pathophysiology behind poorly characterized disease processes in both wild and captive populations. Coagulation profiles, which may include prothrombin time (PT), partial thromboplastin time (PTT), D-dimer concentration, platelet count, and thromboelastography (TEG) are frequently used in domestic species but often overlooked in exotic medicine due to lack of normal reference values and/or availability. Whenever possible, coagulation profiles should be utilized in the evaluation of various disease processes including neoplasia, sepsis, trauma, inflammation, toxin exposure, and envenomation. There are several reports of coagulopathies in both wild and captive species; however, few studies on coagulation profiles have been published on nondomestic species. Clinicians should consider coagulation testing as part of the diagnostic work-up in nondomestic species. A review of available coagulation diagnostic tests is provided here in addition to summarizing the pertinent coagulation disorders currently established in the literature.

Plasmatic coagulation and fibrinolysis in healthy and Otostrongylus-affected Northern elephant seals (Mirounga angustirostris)

BACKGROUND

Prepatent Otostrongylus arteritis results in hemorrhagic diathesis in free-ranging Northern elephant seals (Mirounga angustirostris) attributed to aberrant larval migration of the lungworm, Otostrongylus circumlitus. Clinical signs are often nonspecific, including lethargy, anorexia, and blepharospasm, but can progress to spontaneous frank hemorrhage and death within 72 hours of onset. Previously published case reports describe coagulopathy with prolonged PT and APTT, normal to elevated platelet counts, normal antithrombin concentrations, and low concentrations of fibrinogen degradation products. Disseminated intravascular coagulation was proposed as the cause of hemorrhage, but is inconsistent with some of the reported clinicopathologic changes.

OBJECTIVE

The purpose of this study was to compare plasmatic coagulation and fibrinolysis in healthy and Otostrongylus-affected elephant seals, in order to identify potential therapy. We hypothesized that hyperfibrinolysis contributed to hemorrhage in these cases.

METHODS

Citrated plasma samples were collected from 3- to 4-month-old Northern elephant seals in a wildlife rehabilitation hospital. The sampled population included 25 healthy, prerelease seals and 32 clinically ill seals diagnosed with presumptive Otostrongylus arteritis. Twenty-one of the included seals had Otostrongylus infestation confirmed at necropsy. Standard coagulation tests and plasma thromboelastography were performed for a complete assessment of coagulation and fibrinolysis.

RESULTS

Northern elephant seals with definitive Otostrongylus infestation were hypocoagulable and hypofibrinolytic compared to healthy controls.

CONCLUSIONS

Results were most consistent with disseminated intravascular coagulation. Treatment with antifibrinolytic drugs to control hemorrhage may be unrewarding; alternative therapies such as plasma transfusions or coagulation factor concentrates should be investigated.

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

Cold stress syndrome (CSS) in the Florida manatee Trichechus manatus latirostris has been defined as morbidity and mortality resulting from prolonged exposure to water temperatures <20°C. The pathophysiology is described as multifactorial, involving nutritional, immunological and metabolic disturbances; however, the exact mechanisms are unknown. We hypothesized that thromboembolic complications contribute to the pathophysiology of CSS in addition to the previously described factors. During the winter of 2014-2015, 10 Florida manatees with clinical signs of CSS were presented to Lowry Park Zoo, Tampa, FL, USA. Thromboelastography (TEG) and coagulation panels were performed at admission. In addition, coagulation panel data from 23 retrospective CSS cases were included in the analyses. There were numerous differences between mean values of TEG and coagulation parameters for healthy manatees and those for CSS cases. Among TEG parameters, reaction time (R), clot formation time (K) and percentage of clot lysed after 30 min (LY30) values were significantly different (p < 0.05) between the 2 groups. CSS cases also had significantly higher mean D-dimer concentration and coagulation factor XI activity, prolonged mean activated partial thromboplastin time (aPTT) and significantly decreased mean antithrombin activity. These combined abnormalities include clinicopathologic criteria of disseminated intravascular coagulation, indicating an increased risk of thromboembolic disease associated with manatee CSS.

PROPOSAL AND APPLICATION OF A NOVEL DISSEMINATED INTRAVASCULAR COAGULATION SCORING SYSTEM IN THE FLORIDA MANATEE (TRICHECHUS MANATUS LATIROSTRIS)

  Disseminated intravascular coagulopathy (DIC) is an acquired disorder of hemostasis resulting in activation of the coagulation and fibrinolytic pathways. It is reported secondarily to multiple disease processes and can be associated with increased mortality. Previous research at Tampa's Lowry Park Zoo (LPZ) demonstrated that Florida manatees ( Trichechus manatus latirostris) with cold stress syndrome (CSS) demonstrated thromboembolic disease. The object of this retrospective study was to establish the presence and clinical relevance of DIC in Florida manatees admitted to LPZ for rehabilitation from 07 March 2010 to 15 August 2015. A coagulation panel, including prothrombin time, partial thromboplastin time, platelet count, fibrinogen level, and D-dimer level was used to diagnose DIC. There were 100 cases identified in the study period: 35 trauma, 43 CSS, 17 secondary to harmful algae blooms (HAB), and five miscellaneous. Manatees with CSS had the highest incidence of DIC with 24 of 43 cases (56%) affected, followed by trauma with 18 of 35 cases (52%) affected. None of the manatees with HAB were found to have DIC. Manatees that developed DIC during rehabilitation or when DIC progressed did not survive. Due to the clinical implications of DIC, identifying its presence and recognizing its severity could improve clinical outcomes by enabling more intensive treatment protocols.