Zoo Virus Swap

A polar bear in a German zoo dies after contracting a virus normally found in zebras.

Aug 17, 2012
Cristina Luiggi

Zoos, like elementary schools, can be fertile grounds for all kinds of nasty pathogens, as one unfortunate German zoo recently learned. In the summer of 2010, one of the polar bears at the Wuppertal Zoo died quite unexpectedly after suffering from mysterious epileptic seizures. A brain autopsy revealed the animal had developed encephalitis, or brain swelling, which suggested it had likely died from a viral infection.

Two years and a slew of genetic analyses later, a research team led by zoologist Alex Greenwood of the Leibniz-Institute for Zoo and Wildlife Research (IZW) in Berlin has identified a recombinant strain of the equine abortion virus as the likely culprit. The virus’s natural hosts are members of the horse family, which includes zebras and donkeys.

With the zebra enclosure more than 200 feet away from the polar bears, zoo officials are scratching their heads over how the virus was transferred across the species. But more pressingly, they are worrying about how similar incidents in the future may hinder conservation programs at zoos.

"One of the missions of zoos is conservation of animals, and species-jumping viruses like the one in this study suggest that mission can be threatened if they are undetected," Greenwood told BBC News.

Indeed, it is not the first time the equine abortion virus has crossed species barriers at zoos, Ed Yong, a regular contributor to The Scientist, reported in his blog, Not Exactly Rocket Science. There have been documented cases of the virus killing other species, including bears, guinea pigs, and gazelles.