The Rate at Which Contagions Grow

When an immigrant comes carrying a terrible disease, it's almost 100% susceptible. Then the immigrant starts to mingle with the population. For a while, the epidemic grows. Eventually it doesn't have enough susceptible. It falls below the recovery rate. If this doesn't be clear or not, then the epidemic tails off and slowly declines asymptotic to zero. I think that same model applies to narrative epidemics. The phrase go viral refers to memes or stories on the internet or photographs. When you say go viral, that means go into an epidemic. They're describing an important model.