Mostly from IV drug use, if previous accounts I've read are correct. So? Diagnose them, and throw them in a locked facility to rot. Who cares?!?!?! In other news, Indianans have identified at least 72 worthless wastes of DNA, and pending 7 more. Will there be 100 more? Only if Indiana doesn't take the right corrective action (hint: declaring a SoE is not it).
Heroin.