Scientists discovered the origin of lentiviruses – an HIV-related retrovirus – and found that earliest evidence of the virus date back 60 million years ago.
Viruses are traditionally seen as pretty bad things. In Hollywood, it was always some mysterious virus that left only a few people on Earth or gave rise to a horrific zombie apocalypse. They're the things we think about when we hear "epidemic" or "plague" (even when the black death is actually caused by bacteria). "Virus" is even what we call the pesky malware that can harm our computers. However, according to a new study, there are plenty of "good" viruses out there, too.