Skip to content



Frequently Asked Questions

Nearly-5-year-old African elephant, Ajabu recently dealt with a case of EEHV, a deadly strain of herpesvirus that affects elephants both in human care and in the wild. We’re thrilled to report that Ajabu has made a full recovery! Here are answers to some of the most frequently asked questions about this devastating virus.

What is EEHV?

EEHV (Elephant endotheliotropic herpesvirus) is a type of herpesvirus that can cause fatal hemorrhagic disease in elephants. It is one of the most deadly infections in elephants worldwide, both in the wild and in human care.


Is EEHV preventable?

There is no vaccine or true cure for EEHV, and it is not preventable.


How do we monitor our elephants for the virus? 

Dallas Zoo’s veterinary and animal care team do ongoing behavioral training to establish trust with the elephant herd so the animals will voluntarily participate in their own care and present themselves for blood draws twice weekly. We send these elephant blood samples to the National Elephant Herpesvirus Laboratory at the Smithsonian’s National Zoo in Washington, DC for ongoing testing.

Additionally, the Dallas Zoo is part of a multi-institutional research effort that has been underway for more than a decade to study the virus, identify the various strains, learn about their transmission, develop and improve treatments, and find a vaccine.


How did Ajabu contract the virus? 

Scientists and veterinarians widely believe that most Asian and African elephants both in zoological environments and in the wild have been exposed to and carry EEHV. But, it is not known why the virus becomes suddenly active from its dormant phase, and we do not know what caused the virus to suddenly become active in Ajabu.


What symptoms did Ajabu experience throughout the course of this illness?

In the days leading up to Ajabu’s positive EEHV blood test, he was behaving normally. Veterinarians noted a drop in white blood cell and platelet counts, and aggressive antiviral therapy was started immediately. Ajabu developed lethargy, exhibited edema (swelling) in his legs and a decrease in appetite as his illness progressed, but by managing to start aggressive treatment early, we were able to reduce the severity of the clinical signs.


What treatment was administered?

Ajabu received around-the-clock care from our veterinarians and elephant zoologists throughout his ordeal. He also received four treatments of the antiviral drug, Famcyclovir each day, fluids, vitamins, anti-inflammatories, as well as blood and plasma transfusions and stem cell infusions.


Are the other elephants in the herd affected by this?

We have continued to test samples from all the other elephants within our herd as we would normally. No other elephants in our herd showed any symptoms of disease and have all tested negative.


Why was Ajabu the only elephant in the herd to be affected by EEHV?

African elephants are most at risk for the disease at ages 1-13. Most elephants are able to fight the virus and survive when it comes out of latency. Calves appear to be most susceptible to EEHV disease after they have been weaned, at a time when they are not protected by their mother’s antibodies.


Can elephants transmit EEHV to other elephants?

There is not enough research to confirm how EEHV is transmitted, but most viruses are normally spread from one individual to another. Viral shedding occurs when it comes out of latency (hiding); however, there is no simple way to detect if the virus is active without a blood test. What we do know is that every elephant—in the wild and in human care—probably carries one or more forms of herpesvirus. (Source: Smithsonian’s National Zoo & Conservation Biology Institute)


Can humans or other animals contract EEHV?

Humans and other animal species cannot contract or transmit the virus.


Is the Dallas Zoo now “contaminated” by EEHV?

No. Like all mammals and humans, elephants carry a variety of different herpesviruses throughout their lives, and the majority of them may never cause illness, likely remaining latent (hidden). Some cause mild disease, and some cause severe disease or death. Claims that certain zoos are contaminated once an animal becomes ill from EEHV are unfounded and based on a lack of understanding of how the viruses live within their hosts. Having a herpesvirus is the norm, not the exception. Like many viruses, herpesviruses cannot live very long outside the body, so a herpes outbreak does not “contaminate” a facility. (Source: Smithsonian’s National Zoo & Conservation Biology Institute)