An Elephantine Mystery Is Solved
The killer struck with breathtaking speed. Within hours, it was over--death by massive hemorrhaging in the heart.
An exhausted Joel Parrott, the Oakland Zoo’s director, performed the elephant necropsy himself at 5 a.m., a scant two hours after 11-month-old Kijana, the first African elephant born in captivity in North America to survive past a few months, suddenly collapsed and died in October 1996.
Unknown to Parrott, a similar scene had played itself out at the National Zoo in Washington the year before. Zoogoers there who had just begun to acquaint themselves with a playful pachyderm named Kumari, a 16-month-old Asian elephant, were left stunned.
Now, the two infant elephant deaths, along with eight others across the country, have been linked to a newly discovered herpes virus that is apparently highly lethal when it jumps from one elephant species to another.
The discovery, published in a recent issue of the journal Science, solves a mystery that has baffled zookeepers from Oakland to Florida, and had caused elephant managers to fear the loss of elephants to extinction not just in the wild but also in captivity.
It also could significantly alter the way elephants are treated at zoos, experts say.
Elephants are no longer being imported into zoos from the wild because of their endangered status worldwide, so zookeepers hoping to ensure the species’ survival in captivity depend on the maturation of younger zoo elephants to breed the next generation. Only about 100 have been born in captivity in the last century, with a 30% survival rate.
Records between 1983 and 1996 show 34 Asian elephant births in the United States and Canada. The study concludes that seven of those died of the herpes virus. Moreover, the study indicates that the deaths may have been inadvertently caused by human interference.
The fatal virus, distantly related to the one that causes cold sores in humans, is harmless in African elephants. Only when it is passed on to Asian elephants, which are often placed with their African counterparts in captivity, is the virus fatal.
Researchers believe that a similar crossover phenomenon, occurring in reverse with a slightly different form of herpes virus, led to Kijana’s death, as well as that of another African elephant, in the same period.
The conclusions emerged out of a frantic search for answers in the months after Kumari died.
Kumari had become something of a celebrity in a city of statesmen and civic leaders. Visitors, especially young children, adored the toddling elephant.
A team of 20 doctors conducted a six-hour necropsy on Kumari and spotted the same mysterious hemorrhaging that Parrott was to see in Oakland a year later.
But they were puzzled. Hemorrhaging in animals usually means a bacterial infection, but tests ruled that out.
The first break came 48 hours later, when Laura Richman, then a veterinary pathology resident at the zoo,went back to examine tissue samples under a light microscope. Richman, a native of Whittier, spotted telltale “inclusion bodies,” or dense cellular structures that usually indicate the presence of a virus. But just what kind was uncertain.
A week later, using a powerful electron microscope at the Armed Forces Institute of Pathology, Richman made the biggest discovery of her life: viruses that resembled those in the herpes family.
She immediately called Richard Montali, the zoo’s chief veterinary pathologist.
She knew she was onto something big.
“It’s hard to describe,” she said. “It’s a feeling like you’re the only one on Earth that knows that there’s something there.”
A few weeks later, she attended a pathologists meeting in Illinois. There, she dropped by another zoo where she heard an elephant had died of hemorrhaging.
Suddenly, she had her second case and the inklings of a trend. From then on, “the cases rolled in,” she said.
Richard Garber, a microvirologist in Seattle, contributed an important piece to the puzzle. Using a sophisticated technique that allows researchers to sequence DNA from strands as small as 20 nucleotides in length, Garber confirmed that the virus was genetically different from any type of herpes previously known.
Working on a hunch, researchers scrutinized samples from the skin and genital warts of several healthy African elephants.
They found that the virus was identical to a latent herpes virus that many African elephants carry for their entire lives with no ill effects.
Richman, Montali and others began to pore over a century’s worth of elephant deaths, looking for similar symptoms, including a swollen tongue and trunk and hemorrhaging.
The call for help out of Oakland in October 1996 took researchers by surprise. They had originally thought the disease threatened only Asian elephants.
They put Kijana’s tissue samples through the same regimen of tests as the others and concluded the herpes virus that afflicted her was closely related to but not the same as the one that had killed the Asian elephants.
The researchers cited the Asian-to-African phenomenon in their recently published study, but stopped short of claiming definitive proof that a lethal virus was transmitted from an Asian elephant to an African one.
Nevertheless, they strongly suspect the African elephants were felled by a latent Asian disease.
Scientists are also unsure precisely how or when the virus was passed on.
Even with the gaps, the study may cause significant changes in the way elephants are handled in captivity, zookeepers say. Most zoos, including the Los Angeles Zoo, with limited facilities, keep both species of elephants together.
In Los Angeles, Gita, an Asian elephant, and Ruby, an African, have been together for more two decades, with no apparent ill effects. They appear to be safe, as the disease only seems to threaten infant elephants, said Charles Sedgwick, director of animal house services at the zoo.
“If we were going to breed elephants, we would definitely have to take this into consideration,” he said.
Already, two elephants have been saved by the discovery. Chandra, an 18-month-old female elephant in Springfield, Mo., became sick in 1997. The zoo had lost an infant elephant under similar circumstances several years earlier.
Desperate for anything that might help, veterinarians fed Chandra famciclovir, a drug used to treat herpes in humans.
To their surprise, Chandra recovered.
Another elephant, owned by Ringling Brothers and Barnum & Bailey Circus in Florida, benefited from similar treatment last November.
“All hope is not lost,” Richman said. “If we do have other cases, we can treat them.”