The Oregon Zoo announced last week the death of a ix-year-old Asian elephant named Lily. The elephant succumbed to a sudden onset of endotheliotropic herpesvirus (EEHV), a rapidly progressing and often fatal disease to which calves are particularly susceptible.

“I can’t imagine a more devastating loss for this zoo family and our community,” said Dr. Don Moore, zoo director. “Lily was the darling of the zoo. She was loved by everyone from her elephant family to the people who cared for her every day to her thousands of fans. Our staff did everything they could and fought to save her until the very end. Everyone is in mourning here. It is just heartbreaking.”

On Wednesday, blood sample analyses from the Smithsonian’s lab revealed the virus was active in Lily at very low levels. At that time, Lily showed no known clinical signs of disease. However, the next morning, Lily began to exhibit lethargy and a disinterest in food prompting veterinary staff to begin immediate treatment with fluids and antiviral medication. She also was given a transfusion. Despite these efforts, the disease proved too much for her.

EEHV is known to be present in almost all Asian elephants, both in wild populations as well as those cared for by humans. Often, it remains latent, causing mild or no symptoms, but for reasons unknown it can sometimes come out of latency and cause disease. Once the disease becomes active in calves, it is usually fatal, often causing death within few days even with intensive treatment.

Currently there is no vaccination against EEHV.

The zoo was protested on Saturday by animal rights activists. According to a statement on the Free the Oregon Zoo Elephants website: We are deeply saddened for Rose-Tu, Lily’s mother and her adopted aunties, Chendra and Shine.  Lily’s death is our rallying cry to end the failed breeding program at the zoo, so no more elephants live and die in a zoo, never to know one day of freedom or experience life as a real elephant.