INDIANAPOLIS (AP) _ Health officials say more than 40 people are now participating in a needle-exchange program aimed at containing an HIV outbreak among intravenous drug users in southern Indiana.

Scott County Health Department public health nurse Brittany Combs said Tuesday that 43 people are participating in the program targeting the needle-sharing that's behind the outbreak.

Gov. Mike Pence authorized the limited needle-exchange program solely for the rural county about 30 miles north of Louisville, Kentucky.

Combs says the needle-exchange participants have received more than 1,500 clean needles and have returned nearly 560 used ones.

Those include four people who received clean needles Monday from mobile health workers making their first foray onto the streets of Austin under the program.

That Scott County city of about 4,500 residents is the outbreak's epicenter.