Now that some background information has been established for Herpes Simplex Virus-2, one of the questions that you might be wondering is: “When did humans first get introduced to HSV-2?”.  To answer that, I would have to go WAAAYYY back to the evolution of humans.

HSV-1, which causes cold sores, has been associated with even our earliest ancestors when they split from the chimpanzees, which is not the case for HSV-2. Interestingly, HSV-2 could have been avoided by humans had it not been due to an intermediate hominin species that allowed the virus to re-infect our ancestors. Herpes Simplex Virus-2 was a virus that preyed on African apes; when the precursor human officially split off from chimpanzees they did not take the HSV-2 with them (only HSV-1). It was all thanks to the intermediate hominin species, Parathropus boisei, that HSV-2 got reintroduced to the human species.¹

Scientists hypothesize that HSV-2 may have initially competed with HSV-1 in the mouth of hominins, until it adapted a new environment in the genitals. A virologist from Cambridge University, Dr. Charlotte Houldcroft, stated that HSV-2 would have had to undergo a certain genetic mutation with a combination of copious fluid exchange for the virus to overcome the species barrier and ultimately infect hominins through consumption or intercourse. Once Herpes Simplex Virus-2 invaded Homo erectus, it persisted due to its easily transferrable nature. If you ever happen to get genital herpes and you want someone to blame, you can thank Parathropus boisei; a picture can be found below!

Reference: (1) https://www.sciencedaily.com/releases/2017/10/171001225317.htm