A flesh-eating bacteria, linked to the use of black tar heroin, has killed at least seven people in San Diego County in the past two months.
Southern California health authorities have since issued a new warning.
Thirteen people in Southern California have also been diagnosed with wound botulism since September, which also may be tied to black tar heroin.
Agencies are trying to figure out the source of the heroin.
Flesh-eating bacteria linked to heroin kills 7 in San Diego County