From the start of the HIV outbreak here, health officials emphasized that nothing set Scott County apart from many other rural communities where opioid drug use had become an epidemic. This could happen anywhere, people were told. Many people here had viewed HIV as a big-city disease, something that might afflict people in San Francisco or New York. But Austin is a small city of about 4,000 people 40 miles north of Louisville, Ky.

Then in February 2015, the first 30 cases of HIV were reported. By mid-March, the number had climbed to 55. State health officials, the governor and the federal Centers for Disease Control and Prevention were looking for answers. Few public health crises have unfolded so rapidly. FULL REPORT