The leading cause of mortality among juvenile Asian elephants (Elephas maximus) under human care is elephant endotheliotropic herpesvirus (EEHV).1 As the disease progresses, widespread vascular damage, hemorrhage, and potentially death occurs.2 The purpose of this study was to evaluate the effect of analytic variables (effect of time, activator, repeated pipetting, addition of sodium citrate, and 120 mile transport) when using three viscoelastic point-of-care units to assess Asian elephant blood coagulation. Blood from six healthy (EEHV PCR negative at the time of the study) adult Asian elephants was collected from the ear vein using vacutainers and evaluated at 0.5-, 1-, 2-, 4-, and 24-h post collection using thromboelastography (TEG® 5000 Heomostasis Analyzer System, Haemonetics Corporation, Braintree, MA, USA), rotational thromboelastometry (ROTEM® delta, Tem Innovations GmbH, Munich, Germany), and dynamic viscoelastic coagulometry (Sonoclot® Analyzer, Sienco, Inc., Boulder, CO, USA). All three units allowed the assessment of coagulation. As time progressed blood became more hypercoagulable, although, the use of new blood tubes for each time point led to less substantial changes up to 4 h. Repeat pipetting led to significant hypercoagulability. Native fresh blood was hypocoagulable with weaker clot formation when compared to citrated blood at 30 min. Transported blood sample at 24 h had significant differences when compared with 30 min citrated blood sample. Kaolin and human tissue factor on Sonoclot® analyzer produced a narrower range of clotting variables when compared to glass bead, suggesting that these activators might be more clinically useful. Larger scale studies using these methodologies are needed, as well as evaluation of diseased animals. The information provided by this study will allow for methodology optimization for future studies.
The authors acknowledge the Kirkpatrick Foundation, the Joan Kirkpatrick Chair in Small Animal Internal Medicine, the Oklahoma State University Research Advisory Committee, the Morris Animal Foundation, and the Dr. Kristie Plunkett Exotic Animal Fund for the financial support to this study, as well as the Oklahoma City Zoo and the Tulsa Zoo for their technical support to the study.
1. Fuery A, Leen, AM, Peng R, Wong MC, Liu H, Ling PD. Asian elephant T cell responses to elephant endotheliotropic herpesvirus. J Virol. 2018;92:e01951–17.
2. Kochagul V, Srivorakul S, Boonsri K, Somgird C, Sthitmatee N, Thitaram C, Pringproa K. Production of antibody against elephant endotheliotropic herpesvirus (EEHV) unveils tissue tropisms and routes of viral transmission in EEHV-infected Asian elephants. Sci Rep. 2018;8:4675.