America's Infrastructure begins to destablize.
Disaster / Destruction
As infect rates continue to rise the national guard is unable to maintain order in most of the remaining larger cities and most people begin to lose access to government aid, leaving millions without a reliable source of food and water.
Large cities never stood a chance, places like New York City and Los Angeles were overrun in days with most people in those locations either becoming infected or being evacuated by the National Guard. However now even the larger refugee camps are beginning to be overrun by either the infected or by large groups of organized criminals looking for supplies.