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(THE CONVERSATION) Many Americans now know that, over the past decade, opioid addiction and deaths from opioid overdose in the U.S. have skyrocketed.

But we don’t hear as often about the other epidemics intertwined with this public health crisis. In rural Scott County, Indiana, for example, prescription opioid injections have been linked to overlapping outbreaks of HIV and the hepatitis C virus.

This is a “syndemic”: multiple diseases feeding off of one another, compounding a commu...