What is the other half?
Plague first came to the United States in the 1850's. The rail companies were importing Chinese Coolies to work on the transcontinental railway.
There was a small plague outbreak in San Francisco's Chinatown district. An alert doctor spotted the outbreak almost immediately, and appealed to the city council to institute a quarantine and rat catching program.
The town fathers refused to believe there was plague in their fair city.
They screwed around long enough for it to infect the local ground squirrel population where there was no hope stopping it from spreading. Thanks to their inaction, one can be exposed to plague anywhere in the western US.
Any parallels one wishes to draw with a more recent "gay plague" are left to the reader as an exercise.
Those who do not learn the lessons of the past...