One of the major effects of any epidemic/pandemic is fear and that often leads to panic. People start doing strange things when they deal with the unknown. Many people will simply leave the area (spreading the disease), others will hunker down, buy guns and ammo and prepare like the end is at hand.
I am pretty sure there would have been a lockdown of sorts, but given the mobility of people in the US, it would not have been particularly effective. Unfortunately, as we have seen emotions tend to win and knowledge at the beginning of an epidemic may be very limited.