Woodland Park Zoo Press Release

Fact Sheet: Cause of Death of Asian elephant Hansa

Seattle - At a press conference held today, Woodland Park Zoo announced a newly discovered elephant herpesvirus as the cause of death of Asian elephant, Hansa (HAHN-suh). The disease, which does not yet have a name, attacks blood vessels throughout the body and causes death. The 6_-year-old female elephant died unexpectedly on June 8 after showing only mild symptoms of reduced activity and appetite.

“ We have received a definitive result indicating the death was caused by an elephant herpesvirus never before identified by science,” said Woodland Park Zoo Deputy Director Bruce Bohmke. “The world’s leading experts conducted scores of assays and subsequently had to create a new test over the past three weeks because previous methodologies were unable to detect the virus.”

Two elephant herpesviruses have been previously documented that cause disease and death in wild and captive elephants. “The virus that infected Hansa is a new discovery in the science community that we detected for the first time on June 28 as part of the research into the cause of Hansa’s death,” explained the world’s leading expert on elephant herpesviruses, Dr. Laura Richman, a research scientist at the National Elephant Herpesvirus Laboratory at Smithsonian National Zoo. “The most closely related viruses are the Asian and African elephant endotheliotropic herpesviruses, known collectively as EEHV. But this newly identified virus is not the same as EEHV. Its genetic difference is why it could not have been detected previously.”

Hansa had no other health issues or complicating factors present at the time of death. “There were no clinical signs or laboratory abnormalities to indicate severe disease or an illness that would result in death,” explained Woodland Park Zoo’s Interim Director of Animal Health, Dr. Kelly Helmick. “We performed tests early during Hansa’s illness but the tests were negative for the previously known elephant herpesviruses.”

A team of veterinarians and veterinary pathologists from three other institutions joined the zoo’s veterinary team in performing a necropsy on the elephant. “The first round of testing ruled out several potential causes of death,” explained Bohmke.

The zoo subsequently sent dozens of tests to multiple diagnostic laboratories at leading institutions including the National Elephant Herpesvirus Laboratory at Smithsonian National Zoo, Johns Hopkins University (Baltimore, Md.,), Washington Animal Disease Diagnostic Laboratory (Washington State University, Pullman, Wash.), Northwest ZooPath (Monroe, Wash.), Cornell University, Phoenix Central Laboratory (Everett, Wash.), Michigan State University, University of California-Davis and many others.

According to Richman, there are many unknowns. “We don’t know how Hansa contracted the virus, and we don’t know how common it is,” added Richman. “We will continue to collaborate with several laboratories to characterize and better understand this new disease, which may take months to years.” This unnamed virus will eventually be named by viral taxonomists based on its genetic composition.

Herpesviruses are transmitted from animal to animal and tend to be species-specific. They can remain hidden in an animal for years, never causing disease or death. It is very difficult to detect herpesvirus in healthy animals. Every animal species that has been investigated has viruses. Even in humans, viruses continue to be identified that can result in disease and death.

“ We are extremely grateful to Dr. Laura Richman and her colleagues, Erin Latimer at Smithsonian National Zoo and Dr. Gary Hayward at Johns Hopkins University; and Dr. Mike Garner at Northwest ZooPath (Monroe, Wash.) for their perseverance on identifying the cause of death,” said Bohmke. “And we also are grateful to the many veterinarians and veterinary pathologists who have worked diligently over the past few weeks. Ultimately, their efforts in unraveling this scientific puzzle will help us better understand the epidemiology of elephant herpesvirus and contribute to the body of knowledge that will help preserve this species.”

“ We’d also like to express appreciation, on behalf of zoo staff and volunteers, for the outpouring of support we received from the community. All 1,000 of our animals are unique and special, but Hansa truly was an animal that warmed the hearts of people throughout the region, and we appreciate the hundreds of cards, letters and emails that people sent from the region and all over the world,” added Bohmke.

Hansa, born November 3, 2000, was the first elephant born at the zoo and in the state of Washington. The remaining herd consists of: 28-year-old Chai (rhymes with eye), mother of Hansa; 40-year-old Bamboo, female Asian elephant; and 38-year-old Watoto (wah-TOE-toe), female African elephant. The elephants at the zoo remain healthy.

Additional resource experts:
Laura K. Richman, DVM, Ph.D., Diplomate, ACVP
Smithsonian National Zoo

Dr. Richman is the world’s leading expert on elephant herpesviruses. She was among a team of zoo pathologists who identified EEHV in 1995 while investigating the sudden death of Kumari, a 16-month-old Asian elephant born at Smithsonian National Zoo. She obtained a DVM from the University of Wisconsin-Madison, and completed her pathology residency at the Smithsonian National Zoo. She subsequently completed her Ph.D. in molecular virology at the Johns Hopkins School of Medicine, in the laboratory of Dr. Gary Hayward, studying elephant endotheliotropic herpesviruses.

Michelle Miller, DVM, Ph.D.
Veterinary Advisor for Elephant Species Survival Plan
Disney’s Animal Kingdom

Scott. P. Terell, DVM, Diplomate, ACVP
Veterinary Pathologist and Operations Manager, Walt Disney World Animal Programs
Clinical Assistant Professor, Infectious Diseases and Pathology, University of Florida College of Veterinary Medicine