FWIW
THe initial Zombie attacks were attributed to drug use. A popular street drug that physically resembles bath salts (but are chemically more unpredictable than meth) has been associated with people hallucinating, becoming violent, and due to soaring body temperature, stripping off their clothes. Of course...this could just be a zombie cover story...
Toxicology reports indicate that the face eating zombie was NOT on any drugs. Including bath salts...