OKC Zoo and eight AZA zoos across the country are working together to match donor animals in case of emergency.
A blood-matching database could be the key to saving more Asian elephant lives from the deadly elephant endotheliotropic herpesvirus (EEHV) which affects elephants in human care and in the wild.
“The Oklahoma City Zoo and Botanical Garden is partnering with other Association of Zoos and Aquariums (AZA) zoos in the U.S. to crossmatch Asian elephants’ blood to ensure a rapid response to the fast-moving EEHV virus,” said OKC Zoo’s Veterinary Clinic Coordinator, Liz McCrae. The current blood crossmatching partners are Houston Zoo, Fort Worth Zoo, Denver Zoo, St. Louis Zoo, Columbus Zoo and Aquarium, Cincinnati Zoo & Botanical Garden, Dickerson Park Zoo in Springfield, Missouri, and Rosamond Gifford Zoo in Syracuse, New York.
If a transfusion is given to an animal with incompatible blood, it will cause the cells to lyse, or burst, through an adverse immune response and can lead to hemorrhagic death. Crossmatching blood is critical when doing transfusions.
EEHV has a 65 percent fatality rate in young Asian elephants and once it hits, caretakers must work quickly to save those afflicted.
“In elephants, the herpesvirus is a hemorrhagic virus, which causes massive internal bleeding,” McCrae said. “Transfusing elephants with blood product may help maintain blood volume, replaces platelets, and provides proteins that may improve clotting capability.”
Malee, the first Asian elephant born at the OKC Zoo, was only four years old when she died unexpectedly from EEHV on October 1, 2015. Even though all elephants carry some form of the virus, it usually remains latent. Disease can occur in young elephants when they are exposed to the virus for the first time after maternal antibodies are lost.
The Zoo’s veterinary and elephant care teams had planned and prepared for the possibility of EEHV striking Malee by taking weekly blood samples and developing a response plan, but even then, she succumbed to the virus.
One major factor, they determined, was the time it took to get test results. EEHV testing requires specialized equipment and training and, at the time, they sent blood samples to the Smithsonian National Zoo’s National Elephant Herpesvirus Laboratory in Washington D.C. for testing. To combat this, the Zoo’s veterinary team invested in the necessary equipment and learned how to do the testing in-house. The Zoo has been conducting weekly testing on the elephant herd since June 2017, which resulted in early detection of the virus in Malee’s half-sister, Kairavi, who survived the infection.
While regular testing can help save Asian elephant lives, affected elephants still require aggressive treatment, often including blood transfusions, to fight the disease. Unfortunately, it’s not as simple as matching blood types, as elephant blood types are not yet fully understood. Instead, the OKC Zoo and eight partners are crossmatching blood samples to determine transfusion compatibility in case one of the elephants in their care contracts EEHV. There are plans in the works to crossmatch with additional AZA facilities in the future.
“It takes a fair amount of time to do crossmatching,” McCrae said. “If you wait to do it until you have a sick elephant, it can be too late.”
Collecting large volumes of blood from elephants for transfusion is also difficult and time-consuming, so knowing which donors are compatible in advance speeds up the process and saves lives, she said.
While EEHV was the impetus behind the joint blood crossmatching effort, it has other applications as well, McCrae added. Birth complications, salmonella infection, and other medical issues can also be aided by blood transfusions.
The OKC Zoo is committed to caring for and conserving Asian elephants, leading critical conservation initiatives and collaborating with global partners to ensure a sustainable future for this magnificent species. The Zoo is proud to be the only AZA institution leading Asian elephant conservation in Sri Lanka. In 2023, OKC Zoo established The Sri Lanka Elephant Project, which promotes elephant conservation, research, and reduction of human-elephant conflict. Additionally, three of the Zoo’s expert team members serve on the North American EEHV Advisory Group, a collaborative working group aimed at ending EEHV-caused elephant deaths both in human care and the wild. The Advisory Group is composed of professionals in veterinary medicine, research, elephant care, and outreach who are dedicated to advising and supporting collaborations to prevent elephant deaths from EEHV globally. The Zoo also participates in the AZA’s Species Survival Plan®(SSP) for Asian elephants and supports AZA’s SAFE: Saving Animals from Extinction program for Asian elephants and its strategic conservation education efforts.
Asian elephants are endangered, facing ever-changing environments and challenges including human-elephant conflict that threatens the species’ survival. Wild populations of Asian elephants have fallen below 40,000. The 13 nations that make up the natural habitat of Asian elephants contain the densest human populations on the planet and, as a result, vital habitat for elephants has been reduced by 85 percent over the last 40 years.
The OKC Zoo has been caring for elephants since 1930 and currently has a multigenerational elephant herd of eight Asian elephants consisting of males Rex (56), Kandula (23), and Bowie (10), and females Asha (29), Chandra (28), Achara (9), Kairavi (5), and Rama (2). The herd is growing by one trunk as Achara is expecting her first calf in July 2025.
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