PORTLAND, OR (KPTV) - The youngest member of the Oregon Zoo's elephant family passed away Thursday night, one day before her sixth birthday.

+44 Remembering Lily, the Oregon Zoo's baby elephant Lily was born at the Oregon Zoo on Nov. 30, 2012. She died suddenly from a virus on Nov. 29, 2018.

Zoo officials said despite exhaustive efforts by veterinarians and care staff, Lily died due 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.”

Zoo officials said 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 hidden, causing mild or no symptoms, but for reasons unknown it can sometimes come out and cause disease.

Once the disease becomes active, it is usually deadly, often causing death within few days even with intensive treatment, according to zoo officials.

Zoo officials said blood sample analyses revealed the virus was active in Lily at very low levels on Wednesday. Then the next morning, Lily began to exhibit lethargy and a disinterest in food, according to zoo officials.

Veterinary staff began immediate treatment with fluids and antiviral medication. She also was given a transfusion.

Despite those efforts, zoo officials said the disease proved too much for her.

On their Facebook page, zoo officials said Lily "was with her mother Rose-Tu and surrounded by people who had cared for her since her birth. Her aunties Chendra and Shine also spent time beside her."

Zoo officials say that it has been difficult time for staff who are mourning Lily's death.

The Oregon Zoo will remain closed all day Friday, including during scheduled evening ZooLights. The zoo will reopen on Saturday.

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