Seattlepi.com
July 3, 2007
By Carol Smith

Original Article

Hansa, Woodland Park Zoo's 6 1/2-year-old elephant, died of a previously undiscovered herpes virus, Zoo officials announced Monday.

- Photo gallery of Hansa's life (accessed from original article)

The as-yet unnamed virus is different on a genetic level than the more familiar types of herpes viruses that are known to affect Asian and African elephants, both in captivity and in the wild, Zoo Deputy Director Bruce Bohmke said.

Herpes is especially deadly for elephants younger than 10, Zoo veterinarian Kelly Helmick said. Of 21 known cases among elephants of all ages in North American zoos since 1983, only three survived herpes. Scientists do not know how any of the herpes strains are transmitted among elephants, although it is known that they can harbor the virus for many years and never appear ill.

There is no known cure for herpes in elephants, she said. A vaccine is still many years away. Elephants can be treated with the same antiviral drug used to treat human herpes, but the results to date have not been very successful, based on the survival rates.

Hansa was tested for the known herpes viruses when she fell ill in late May, and the test was negative, Zoo officials said. In hindsight, the negative finding occurred because the existing test could not detect the new type of herpes. Scientists are in the process of developing a genetic test that can detect the new type of herpes in elephants, as well as an antibody test that can detect whether an elephant already had the virus.

Herpes viruses infect most species, and typically are species specific, meaning they don't cross over among different types of animals. For example, nine types of herpes viruses are known to attack humans. The human virus is genetically different than the elephant virus.

The newly discovered herpes virus that killed Hansa attacked the blood vessels throughout her body, Helmick said. Hansa did not exhibit the typical symptoms for a known herpes infection, which include development of a swollen, purplish tongue and rapid death.

Hansa, an Asian elephant that was born and raised at the Zoo, was found dead June 7 after a brief illness. The popular young elephant had shown signs of reduced activity and appetite, and "coliclike" symptoms in the week or so before her death. Lab tests and clinical examination showed no signs of disease, however, and she appeared to be improving just before her death.

After her death, a team of veterinarians and pathologists from three institutions performed a necropsy.

According to early test results released June 22, the team ruled out sand colic, gastric torsion, foreign-body obstruction, salmonellosis, cancer or any form of genetic or nutritional disease.

The Zoo then began sending tissue samples to a half-dozen institutions, including Johns Hopkins University, the Smithsonian National Zoo and the University of California, Davis.

The virus eventually was identified by Dr. Laura Richman, a research scientist at the National Elephant Herpesvirus Laboratory at the Smithsonian zoo in Washington, D.C.

"The most closely related viruses are the Asian and African elephant endotheliotropic herpesviruses, known collectively as EEHV," Richman said Monday. "But this newly identified virus is not the same as EEHV. Its genetic difference is why it could not have been detected previously."

Woodland Park Zoo is in the process of notifying elephant keepers around the country of the findings, Bohmke said. Zoo is monitoring its other elephants, which all appear healthy.

Although the mode of transmission of this particular virus is unknown, other herpes viruses are transmitted through close contact from animal to animal, Richman said. Some may be transmitted from mother to offspring through the birthing process.

It's also not understood why the virus causes some animals to get sicker than others.

The Smithsonian lab plans to go back and look at previous elephant deaths around the country to determine whether the newly identified virus may have been a factor, Richman said.

Maria French, president of the Northwest Animal Rights Network, said she hoped the United States Department of Agriculture would investigate Hansa's death and shed additional light on what happened.

Mark French, the network's treasurer, said he doubted that herpes was the sole cause of Hansa's death, citing her habit of eating sand. He criticized the Zoo's investigation for not allowing scientists from activist groups to participate.

"We're really mourning the loss of Hansa," Maria French said, adding that the group advocates the release of the Zoo's remaining elephants to a sanctuary in Tennessee.

The Zoo's elephant keepers and veterinary staff also continue to mourn Hansa's death, but the outpouring of sympathy and support from around the country has been some solace, said Nancy Hawkes, who curates the Zoo's elephant exhibit.

"I can't tell you what a help it has been for the staff," she said.

The Zoo's three remaining elephants have resumed their normal routines after a brief period in which they appeared to acknowledge Hansa's passing, she said.