(CNN) Seven people in San Diego have died in the last two months from a flesh-eating bacteria associated with black tar heroin use, according to health officials.

Nine people who injected the drug were admitted to hospitals in San Diego County with severe myonecrosis between October 2 and November 24, the San Diego County Health and Human Services Agency announced in a news release Wednesday.

The patients ranged in age from 19 to 57 years old, the statement said. Only two survived.

Myonecrosis is a severe soft tissue infection that destroys the muscle. Symptoms often include severe pain near the injection site, swelling, fever, blisters and pale skin that changes to dark red or purple.

Another rare illness associated with black tar heroin injection was reported in San Diego County in October, the statement said. It was the county's first confirmed case this year of wound botulism -- a serious illness that attacks the body's nerves. Seven cases were reported last year and three in 2017.

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