The Palm Beach Zoo mourns the death of Abby, a four-year-old Queensland koala, who was found deceased in her habitat at 11 p.m. on Saturday, November 2, 2013. Her last weight check was on October 27, 2013, at which time she was found to be at a normal weight and in estrus. Zookeepers said both of those factors indicated she was healthy. They had been monitoring Abby very closely, as she had tested positive for a virus that has been recently found in both wild and captive koala populations. The effects of this virus are unknown.
The virus, discovered just this year, is called “Koala Retrovirus B (KoRV-B).” KoRV-B is an immune deficiency virus associated with leukemia and lymphoma, according to a study done with help from the San Diego Zoo. The study shows that the KoRV-B infection is passed along from mother to joey (baby koala). Research shows the virus weakens the immune systems of koalas that are infected, similar to HIV in humans.
Although it is still too early to draw a definitive conclusion about the cause of Abby’s death, Jan Steele, General Curator of the Palm Beach Zoo, believes the koala may have had an infection, possibly related to the new virus KoRV-B. “From the preliminary necropsy (animal autopsy), it was determined that she had enlarged lymph nodes and digestive tract bleeding, even though she had been eating normally,” said Steele. “Whatever it was that caused her death came up very suddenly, giving us little time to diagnose or treat her symptoms.”
On Saturday at 11 p.m., Zoo staff saw Abby was on the ground and unresponsive. They notified the Zoo’s veterinarian, general curator and associate curator of mammals, who immediately went to the habitat, but they were unable to revive her. A preliminary necropsy was performed that night, but a definitive cause of death has yet to be determined. Tissue samples have been sent to a laboratory, with results expected in several weeks.
“The most difficult part of zoo life is losing an animal that we have come to know and love,” said Steele. “Deaths, like births, are part of the zoo experience. Although you expect to see a certain number of animals die over time, it doesn’t make it any easier, especially when it’s an animal as well-loved as Abby.”
Steele is confident about the quality of care all animals receive at the Palm Beach Zoo. She said animals typically have longer life spans in zoos than in the wild because of healthful nutrition, good medical care and the lack of predators. But detecting illness in an animal can be challenging, even under close watch.
Abby came to the Palm Beach Zoo from the Los Angeles Zoo in 2010. She lived in the “Koala Forest” habitat with Oz, a male Queensland koala. Koalas are found only in Australia, and their numbers are threatened by loss of habitat and global climate change. The Palm Beach Zoo was chosen by the Association of Zoos and Aquariums to participate in the long-term Koala Species Survival Plan breeding program. Abby and Oz had not yet produced a joey.
A sign commemorating Abby with her photo and history will be placed at the Koala Forest exhibit. Oz will move to another zoo in the hopes of breeding. A new koala pair will eventually come to the Palm Beach Zoo, through participation in the Species Survival Plan.