Viral Dark Ages and Clarifying the Definition of a Virus

It's finally Spook Month here on Advent of Computing! To kick things off I'm tackling a bit of a mystery. Between 1972 and 1982 there is only one well documented virus. This period is book ended with plenty of sources and, yes, even viruses. But this decade long span of time has almost nothing! Was this era truly safe from the grips of malicious code? Or is there a secret history lurking just beneath the surface?   Selected Sources:   https://dl.acm.org/doi/pdf/10.1145/358453.358455 - Worms at Xerox PARC!   https://archive.org/details/crimebycomputer0000park - Crime by Computer   https://archive.org/details/dr_dobbs_journal_vol_05_201803/page/n89/mode/2up - Programming Pastimes and Pleasures