EEHV research

Fighting elephant endotheliotropic herpesvirus (EEHV)

Elephant endotheliotropic herpesvirus (EEHV) is a naturally occurring virus affecting Asian elephants living in the wild and in zoos. A latent, or hidden, phase of the virus can reside in its host with no signs or symptoms. If it comes out of latency and circulates in the bloodstream, it can cause diseases and even death, especially in weaned calves. There is no known cure for EEHV.

The National Elephant Herpesvirus Laboratory at the Smithsonian's National Zoo collaborates with Johns Hopkins University and accredited zoos to study and develop a vaccine for EEHV-related diseases. The Oregon Zoo has partnered in this effort through financial and scientific support since the lab began work.

As with human herpesviruses, the transmission and treatment of EEHV largely remains a mystery to scientists. Herpesviruses are undetectable in their latent phases – both humans and elephants can carry herpesviruses their entire lives without any symptoms or ill effects. Antiviral treatments can suppress EEHV, and treatment can lead to recovery in some elephants if the active virus is detected early. For this reason, elephants at the Oregon Zoo and most other accredited zoos are tested weekly.

EEHV poses a significant threat to the survival of Asian elephants as the species faces growing pressures from habitat loss, poaching and conflict with humans. The collaborative pursuit of a vaccine is critical to the future management of both zoo and wild elephants.