Several studies found that many people who have never showed any outward symptoms are in fact infected. A large scale study in Canada revealed that 45 percent of women who never had any symptoms were infected with herpes. 45! So before you close this tab thinking “Uhm, sorry, jerk, but I don’t have any herpes,” I can tell you: Don’t be so sure.

Viruses are fascinating creatures. They’re not officially deemed to be alive, but somehow they do have a kind of purpose in life. In the words of the Reddit virologist, “They are little bundles of genetic material that only really care about making more little bundles of genetic material—and some of them do it really, really well!”

One of those little bundles of genetic material is herpes. According to some scientists, it had been around for over 100 million years, and has evolved to be able to infect most mammals, some fish, and even bivalves like the Pacific oyster.