Dr. Marjorie Bercier Publishes Study on Novel Diagnostic Approach for Prevalent Elephant Virus

Dr. Marjorie Bercier, IPSAV, ACZM, MG24 (MPH), (she/her) has published the first in a series of studies into Elephant Endotheliotropic Herpes Virus (EEHV), the leading cause of death among young Asian elephants and highly lethal in African elephants, aimed at catching the disease before it’s too late.

Bercier is on the Zoological Companion Animal Medicine (ZCAM) team at Henry and Lois Foster Hospital for Small Animals (FHSA) and an assistant professor in the Department of Clinical Sciences at Cummings School of Veterinary Medicine at Tufts University. Her study, “Reference Intervals for D-Dimer Concentration, Fibrinogen Concentration, and Automated Platelet Count in Juvenile Asian (Elephas maximus) and African (Loxodonta africana) Elephants without Elephant Endotheliotropic Herpes Virus (EEHV),” appeared in the June issue of the Journal of Zoo and Wildlife Medicine.

EEHV causes hemorrhagic disease (EEHV-HD), a condition that typically exhibits no clinical signs until it’s progressed too far along to treat successfully. Most young elephants that contract EEHV-HD die within a week. The goal of Bercier’s research is to develop a scoring system with a species-specific reference interval to identify indicators of EEHV while it’s still treatable.

“You can detect the virus in the blood. If you start treatments in the earlier phase, there’s some success in saving lives. So finding a diagnostic tool that would enable us to make that diagnosis very early is extremely important and a priority for the elephant veterinary community,” explains Bercier.

Current recommendations are for zoo veterinarians to send elephant blood samples to a laboratory for EEHV PCR testing. In her paper, Bercier proposes additionally testing elephant blood samples for concentrations of D-dimers (proteins that indicate destruction of blood clots), fibrinogen (proteins emanating from the liver that help form blood clots), and platelet counts (involved in making blood clots), utilizing a new reference interval developed from this research.

The study included 24 African and 20 Asian elephants from zoos across the United States, all healthy, between the ages of one and 15. Zoo veterinarians submitted blood samples to evaluate for D-dimer concentration, fibrinogen concentration, and platelet count.

Initial research on this project began two years ago with a pilot study to determine if D-dimers could be measured in elephant plasma. With the help of a Cummings School summer research student, Bercier obtained blood samples from elephants in zoos in Rhode Island, New York, and Tennessee to confirm her hypothesis. From there, she launched a multi-institutional project of two parts: the first to establish a reference interval based on blood samples from healthy elephants (this current study), and the second (still underway) to look for commonalities in the blood of elephants with the virus.

“The first step is to determine what the normal levels of D-dimer, fibrinogen, and platelets are in healthy juvenile elephants,” says Bercier. She is still collecting blood samples from elephants with EEHV to complete the second study.

Bercier conducted the research in collaboration with Dr. Marjory Brooks, laboratory director of the Comparative Coagulation Section of Cornell University College of Veterinary Medicine, and Erin Latimer, research specialist with the National Elephant Herpesvirus Laboratory at the Smithsonian’s National Zoo and Conservation Biology Institute.

In determining the most optimal diagnostics for detecting EEHV, Brooks suggested D-dimers based on her previous research with the protein. She ran partial CBC and hemostatic protein assays to assess D-dimer concentrations in the blood samples, utilizing an analyzer at Cornell’s Animal Health Diagnostic Center. Latimer performed the PCR tests on the blood samples to ensure the elephants continued to test negative for EEHV. (For the second study, Latimer is looking at blood samples of elephants infected with EEHV.)

There has been evidence that EEHV-HD can lead to disseminated intravascular coagulation (DIC), a syndrome that can cause multi-organ failure and death in both humans and animals. Difficult to diagnose, DIC can be detected in humans, dogs, and horses through a scoring system of platelet count, fibrinogen concentration, and D-dimer concentration. The researchers extrapolated this scoring system of biomarkers to detect DIC in elephants, indicating the presence of EEHV-HD.

“The ultimate goal is to create a new DIC scoring system so that any zoo veterinarian suspicious of hemorrhagic disease can run and interpret these tests,” says Bercier. “Hopefully, within the next five years, we will have this scoring system to help veterinarians around the world deal with this condition, and help in the decision-making process.”

The paper recommends weekly CBCs and whole blood EEHV qPCR for captive juvenile elephants, and for those at risk of EEHV, also monitoring D-dimer, fibrinogen, and platelet counts, with this new reference interval to compare against.

Giving kudos to the zoo veterinarians that participated in the study, Bercier says, “Zoo vets are the ones at the front lines dealing with these situations. It takes a village to treat this disease, and only collaboration makes it possible. If I can help with making the diagnosis sooner, hopefully elephants will not get as sick.”

Originally from Canada, Bercier earned her D.V.M. and completed her Internship in Applied Veterinary Sciences at the University of Montreal. She worked for a year as a small animal veterinarian at a hospital in Quebec before her residency in zoological medicine at the University of Florida College of Veterinary Medicine. As part of her residency, she worked as a veterinarian for the animals at Walt Disney World’s Animal Kingdom and EPCOT parks, providing her first experience treating elephants.

“Elephants are incredibly smart. They play tricks on each other. They’re a caring, matriarchal, and gregarious species. They’re the biggest land mammal out there. It’s really special to be able to work with them and be around them,” says Bercier.

For several years, Bercier was a veterinarian at Cheyenne Mountain Zoo in Colorado and later Zoo de Granby in Quebec. She regularly attended EEHV symposiums and conferences to keep up to date on the latest findings in diagnosis and treatment. When she learned that the condition, mainly seen in Asian elephants, was emerging in African elephants too, she says her interest was piqued.

Bercier joined Cummings School six years ago in the ZCAM service. While also earning her Master of Public Health from Cummings School and Tufts School of Medicine, Bercier worked with Latimer on her capstone project, a large retrospective epidemiology study analyzing measures of disease frequency for EEHV in elephants, based on the Smithsonian’s dataset of all PCRs performed on elephants in the United States since 2014. While there are many case reports of EEHV, Bercier’s research is the first comprehensive study documenting how EEHV presents in terms of CBC values, clinical signs, bloodwork abnormalities, and outcomes. She is finalizing the manuscript and will present the results at the EEHV Advisory Group Symposium and the American Association of Zoo Veterinarians (AAZV) Annual Conference.

“The data hasn’t been published anywhere,” says Bercier. “I’m excited for that to come out because it will give a lot of insight.”

Bercier is additionally researching portable analyzers that zoos could use to look at D-dimers in-house, with two companies signed up to provide the analyzers. Bercier will compare the results against the Cornell analyzer to ensure accuracy. Outside of the U.S., most countries do not have access to laboratories that can run these tests.

“If it’s similar, then we can tell zoo vets in Europe and other range countries that they can purchase this portable analyzer and run D-dimers bedside or in the field with immediate results,” she says.

Cummings School veterinary students have helped tremendously with Bercier’s research. In addition to the pilot study, a summer research student she mentored helped validate a methodology analyzer for elephant platelet counts, a study currently under review for publication. Bercier plans to complete the portable D-dimer analyzer study this summer with another Cummings School student.

Bercier has published a plethora of research related to bearded dragons, parrots, white rhinos, koalas, donkeys, rabbits, and snakes—this is her first on elephants.

“With this research, I think I found my niche,” she says. “I feel privileged to be able to do this kind of research.”