Quite a while ago, two polar bears living at a zoo in Germany became gravely ill. Unfortunately, out of the two, only one managed to survive, in spite of efforts made to save them both.
Once an autopsy was performed on the dead polar bear, it was learned that a viral infection caused a swelling in its brain, and that this was the cause for which the animal started seizing and passed away.
Naturally, the zoo's staff was pretty much interested to learn how these two top predators became infected, in order to prevent such incidents from happening again in the future.
Thus, after thorough investigations, it was discovered that what killed the bear was a combination of herpes viruses typically found in zebras. Seeing how these two species never came in direct contact whilst at the zoo, it still remains a mystery how the viruses got from the herbivores to the polar bears.
However, as specialists Alex Greenwood explains, “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.”