Mickey most likely contracted hepatitis through his iv drug use. (Intravenous drugs). The most of drugs which are used among iv users are;
Opiates, Heroin, Cocaine, Prescription drugs.
IV drugs can cause fatal health complications, for example,
increased risk of blood-borne disease
Abscesses
Infections
Increased chance of overdose
Collapsed veins
Some of the signs of iv drug use are;
Track marks on arms.
wearing of the long sleeve in warm weather.
Swollen feet and hands.