Zoo elephant's health is being carefully monitored
This article first appeared in the St. Louis Beacon, Feb. 13, 2009 - An elephant at the St. Louis Zoo remained in stable condition Friday afternoon as she undergoes treatment for a potentially fatal herpes virus.
Jade, a 23-month-old Asian elephant, is receiving around-the-clock care from Zoo veterinarians and curators. She was lethargic on Sunday, and a blood test showed the presence of herpesviral DNA. Jade has since been taking anti-viral medication and receiving fluids. There is no vaccination for the endotheliotropic herpesvirus (EEHV).
Bill Houston, assistant general curator for the Zoo, said Jade has been alert, active and is eating. She was staying indoors with her grandmother, mother and half-sister.
"Every day she's in stable condition is a day in her favor," Houston said. "This is a potentially serious disease, and things can progress very quickly."
It's not known how Jade contracted the herpes virus. Houston said there's nothing to indicate that other elephants who came into contact with Jade are at risk. Her half-sister is being closely watched and is receiving prophylactic treatment.
"We have a pretty comprehensive health monitoring program," he said. "There's not a lot of concern about the general elephant herd. We're confident that, with the exception of Jade, there are no immediate concerns on the horizon."
The daughter of Raja and Rani, Jade was born at the St. Louis Zoo. Houston said this is the first known case of the virus for an elephant at the Zoo. The virus is most often found in elephants under seven years old.
Researchers at the Smithsonian National Zoo and Johns Hopkins School of Medicine identified EEHV in 1995 after the first elephant ever born at the Washington, D.C. zoo died mysteriously several days after becoming ill from a virus. Since its discovery, EEHV has been identified in elephants in the United States, Asia and Europe.
Laura Richman, a research associate at the Smithsonian National Zoo who helped discover EEHV, said there are multiple forms of the virus. It can be deadly because it attacks cells that line the inside of blood vessels, causing internal bleeding. The virus has killed elephants in the wild and in zoos.
Because researchers aren't sure how many deaths occurred before the virus was uncovered - and how many elephants have contracted EEHV in the wild - it's difficult to determine a survival rate. Richman, who oversees the National Elephant Herpesvirus Laboratory, said she is working on retrospective studies that look at cases of animals who died in the wild.
Researchers still aren't sure how most elephants contract the disease. Viruses in general can be transmitted through the placenta, but "the picture of this disease doesn't fit that scenario," Richman said.
"Logic dictates that it could be any type of contact - saliva, trunk, eye, any kind of fluid exchange," Richman said. "It's not uncommon to hear the story [like Jade's] of a young elephant getting the virus and no one around her having it."
Once elephants in a zoo are exposed to the disease, Richman said it doesn't make sense of keep them separated from each other.
The herpes virus is species specific, and Richman said there's a large genetic difference between the virus that affects humans and elephants. There's no evidence that EEHV is dangerous to people.
The St. Louis Zoo is involved in a multi-institutional research project to learn more about EEHV. Richman is working with a team of researchers on vaccines and therapies.
"This is a new disease in terms of how we deal with elephants once they've been diagnosed," Richman said. "We want to combat this and understand what's happening in the wild."
Elia Powers is a freelance writer.