There’s a well-known doctor saying: “When you hear hoofbeats in Central Park, don’t expect zebras.” The idea is that the symptoms you’re looking at probably don’t indicate a super-rare disease, even if you Googled them and Dr. Internet told you that you definitely have pernicious porphyria or whatever. But apparently that’s off the table for polar bears. If you’re a polar bear and you have a weird disease, go ahead and suspect zebras, because you’ve probably acquired zebra herpes.

At least, that was the case in Wuppertal Zoo in Germany, where two captive polar bears started having seizures in 2010. When one of them died, zookeepers performed an autopsy and discovered inflammation in her brain — caused, they found, by a herpes virus that infects equines like horses, donkeys, and zebras. The polar bear, who had the hilarious name of “Jerka,” was killed by a mutated form of the virus that she caught from the zoo’s zebra population. (Who are the REAL jerkas here? I submit that the zebras are.)

This virus is unlikely to affect polar bears in the wild, which is good because they have their own shit to deal with without worrying about getting zebra herpes. But it’s wreaked havoc in zoos before, killing black bears, gazelles, and guinea pigs (and other polar bears, too). If zoos are going to keep preserving threatened animals, the zebras are going to have to learn to keep their herpes in their pants.