I remember reading some years ago a worst case scenario for African Ebola was it reaching a large city... this fear was usually dismissed because people became sick in a debilitating fashion very quickly with earlier versions of the virus. They were not going to walking or riding to cities...
When this outbreak started one of the early reports was from a doctor who commented that people with the disease looked 'healthy' almost up until the point they died. That's a nightmare situation if the concern is the number of people that could be infected by one person. One person with the virus - in a bed - very sick and unable to move around much is safer than a person who can get up with the virus and spend a few days walking around town infecting hundreds...
A sick person in a bed is almost where it gets scary. Imagine Ebola in San Francisco's gay community. It's quite possible that it will spread earlier in the course of the disease with larger volumes of fluids exchanged, and only about 15% of gay men with HIV tell their hook-up partners that they are infected. Even fewer would mention that they have a fever or are feeling a little sore. How many would wait 90 days after recovery before putting strangers at risk? This could get out of control quickly in certain circles, and then Obama would finally care. The sad thing is that conservatives object to that risk and want it minimized, while the far left wants borders to stay open at any cost - America's enemies in the White House value new undocumented democrats more than they value the lives of gay Americans.