With hepatitis C virus (HCV) rates spiraling out of control across the U.S. Appalachian region, a sheriff in East Tennessee has reported that almost all of the inmates in his county jail have tested positive for the liver disease, Knoxville’s WATE.com reports.

After drawing the blood of a few dozen inmates, medical staff at the Claiborne County jail found that an astounding 92 percent of the tests came back positive for HCV. After asking a couple of questions about risk factors, they found that injection drug use was to blame, and that makeshift jailhouse tattoos were further transmitting the virus.

Claiborne County Sheriff David Ray, who ordered the tests, said he is now working with the state health department to help curb the spread of HCV and get treatment into the jail. In the meantime, prison staff will test all 250 inmates.

Ray said the high rates of hep C aren’t just an issue for his prison population—they’re a major concern for the region as a whole. According to U.S. Centers for Disease Control and Prevention (CDC), there has been a 364 percent increase in HCV infections across Appalachia during the past five years.

Regional reports show the disease is mainly spreading in rural areas among people younger than 30, who started out abusing prescription pain pills and eventually moved on to injecting drugs.