By way of comparison the mortality rate of the Spanish Flu was 2.5%. That's two and half percent. On average 2 and 1/2 people out of every 100 would die.
With the current strain of Ebola 70 out of every 100 die WITH treatment. Ninety out of a hundred are dying without treatment.
Spanish Flu infected 28% of Americans. If Ebola infects 28% of Americans today that would mean about 89 million people catch Ebola. If 70% of them died, that would mean that about 62.5 million people would be dead in the US alone. That's somewhere around 1/5 of all Americans would be dead if Ebola spread to just 28% of the population.
And it would be fast. The hospitals and medical staff would be hit hard, and hit first.
Consider that 70% of medical personnel would be hit.
Your death rate increases significantly if no one is left to treat the sick. Heart attacks, strokes, accidents...the mortality rate for everything else will skyrocket.
Your 62 million could easily pop up to nearly 100 million pretty darned soon.
I doubt the country could make it through a Spanish Flu mortality event these days. That would be somewhere in the neighborhood of 7.5-10 million dead in one season.
When urban areas start to rack up numbers, how long will the first responders stay on the job? The guys picking up trash? The power plant crews? Transit workers?