How about we use these observations to play the game:
Measles: mild, common, with a short latency and little mutability
Ebola: high severity, low prevalence, short latency, medium-high mutability; flu: moderate severity, high prevalence, and short latency.
Hantavirus: strong symptoms, uncommon, long incubation period, limited genetic diversity
COVID-19: frequency is high, latency is short, and…