The number of people infected in southeastern Indiana’s HIV outbreak has grown to at least 120, up by more than 20 in the last week alone, the state health department said Friday. Another 10 infections are awaiting confirmation.

The scale of the outbreak in the remote Scott County, home to around 25,000, caused alarm for health officials. The rapid growth in infections appeared to stem from the sharing of needles by intravenous drug users.

“This sharp increase in the number of HIV-positive cases demonstrates just how critical it is that we are able to locate and test people who have been exposed so that they can avoid spreading it to others and get medical treatment,” said State Health Commissioner Jerome Adams in a press release.

Indiana Governor Mike Pence declared a state of emergency last month, and the Centers of Disease Control and Prevention (CDC) sent staff to Indiana to investigate. More than 5,300 syringes have been provided to local residents after a needle exchange program began earlier this month.

“This community has been dealing with used syringes being tossed in yards and public areas for a long time, but I want to stress that it’s not safe to pick up syringes,” said Adams.

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Write to Justin Worland at justin.worland@time.com.