By Sergio Acuna Gutierrez, Cornell DVM ‘26

As a veterinary student interested in specializing in zoological medicine, I had the privilege of conducting research focused on investigating the effects of hetastarch on coagulation in Asian elephants, with the goal of supporting the development of treatment recommendations for elephants in hemorrhagic crisis. But before I get ahead of myself, allow me to share the inspiration for this project, conducted under the guidance of Dr. Noha Abou-Madi, associate clinical professor in zoological medicine at the Cornell University College of Veterinary Medicine.

Crisis Among Giants

In my mind, elephants are one of the most iconic animals associated with conservation, wildlife, and zoos. While many people are aware of the many anthropogenic impacts on wild elephant populations, another critical threat looms over both wild and captive elephants: elephant endotheliotropic herpesvirus (EEHV).

Primary infection with EEHV often causes a massive and uncontrollable hemorrhagic disease (EEHV-HD), which is a leading cause of death for captive Asian elephants worldwide. The mortality rate is 65% despite treatment, and successful intervention is challenging due to the disease’s acute onset, often resulting in fatality within 24 hours of clinical presentation. Surveillance for signs of viremia (virus in the blood) is essential in detecting EEHV-HD infection, but early and aggressive treatment is crucial for addressing its rapid and severe pathogenesis.

Current treatment recommendations rely heavily on empirical evidence, as there are significant challenges that limit our ability to conduct research on drug efficacy and interactions in elephants. Hydroxyethyl starch (hetastarch) is a synthetic colloid often used to treat or prevent a drop in blood volume and blood pressure in human and veterinary medicine, noting that it also interferes with coagulation (blood clotting). Some clinicians have advocated for use of hetastarch in conjunction with blood transfusions to help manage EEHV-HD. However, there is a lack of information regarding its effects in non-domestic species. In elephants, decreased coagulation potential during a hemorrhagic crisis could worsen their disease state. Therefore, my project aimed to investigate the in vitro effects of hetastarch on specific Asian elephant coagulation parameters in order to shed light on the concerns over its use in elephants and support the development of future EEHV-HD treatment recommendations.

Colossal Challenges: Inside the Elephant Research Process

My investigation was comprised of two key components: sample collection and assessing coagulation. The first objective involved obtaining blood samples from Asian elephants and collecting plasma. Proper collection and processing were crucial for accurate coagulation testing. Thanks to director Dr. Marjory Brooks and associate clinical professor Dr. Robert Goggs of the Comparative Coagulation Lab at the Animal Health Diagnostic Center, we developed a thorough protocol ensuring proper sample collection, processing, and storage.

Blood sample collection was made possible by collaborating with the dedicated Rosamond Gifford Zoo staff and six magnificent elephants under their care. I had the privilege of witnessing the results of impressive training that allowed for voluntary blood draws, with elephants presenting their ears to staff members for quick sampling. With plenty of time, trust, and treats, I saw how the zoo could provide safe, stress-free medical procedures for the myriad of animals under their care. Following blood collection, platelet-rich plasma was extracted from the samples and taken to the Comparative Coagulation Lab.

The second phase of the project involved conducting in vitro plasma treatments and performing coagulation testing. Plasma samples were diluted with incremental amounts of hetastarch to mimic treatment doses administered to elephants in a clinical setting. A similar protocol using saline solution was carried out to distinguish the effects of drug interaction from the dilutional impact of fluid administration.

Once plasma samples were treated with saline or hetastarch, coagulation parameters were measured to assess the potential influence of hetastarch. This included evaluating clotting factors, which are proteins crucial for the clotting process, and clotting times such as prothrombin time (PT) and activated partial thromboplastin time (aPTT). Each parameter provides insights into the physiological processes involved in coagulation, and this baseline information is needed to then help discern how the presence of hetastarch might alter the coagulation process.

Developing this protocol highlighted the challenges of conducting research in wildlife medicine. Mimicking a fluid bolus in an elephant requires knowledge of their blood volume and treatment dosages. The exact blood volume of an elephant has not been determined. Various sources have suggested that an elephant’s blood volume can be between five and ten percent of its body weight, but this seemingly narrow range can mean a difference of 350 pounds of blood! Based on discussions with veterinarians who specialize in elephant medicine, we opted for an estimated blood volume of 8% of total body weight. Clinical evidence suggests that small doses of hetastarch seem to be most effective, but since there is limited knowledge of hetastarch dosing in elephants, there is a need for further research.

The Road Ahead: Continuing EEHV Research

In the next few months, I plan to create a summary of these findings and present these results at a national or international EEHV meeting. I am grateful to the Cornell K. Lisa Yang Center for Wildlife Health and their Student Support Fund, as well as the Rosamond Gifford Zoo, for generously providing the resources, time, and elephants to conduct this important work.

This project broadened my perspective on clinical research—particularly its application to improving medical practices in wildlife. I also gained a great sense of achievement from being involved in the project, from inspiration to completion. I hope this work will help further investigations on EEHV-HD to decrease mortality rates in elephants.

Sergio Acuna Gutierrez is a third-year (Class of 2026) DVM student at the Cornell University College of Veterinary Medicine. Acuna Gutierrez is interested in zoological and conservation medicine, stemming from a deep fascination with the beauty woven throughout the diverse world of wildlife. He aims to contribute to the health, well-being, and conservation of wildlife and natural habitats.

Photos provided by Sergio Acuna Gutierrez, unless otherwise noted.