Ebola moved around in the 80s, we just were to busy to notice until 2014. Perhaps a different less lethal strain went off the radar until the carriers could no longer carry it. A strain with a lethal outcome in individuals with older or weaker immune systems? We lost track of Ebola in the 80s and it did move around. Multiple locations with confirmed antibodies for Ebola have been found.
https://theconversation.com/africas-missing-ebola-outbreaks-80301
https://www.smithsonianmag.com/science-nature/living-bacteria-are-riding-earths-air-currents-180957734/
Hope not airborn …☠☠ worse than black death if so well see