Hennepin County officials unveiled a plan Thursday to reduce the spread of HIV, starting with outreach to residents who have the infection but are not receiving treatment.

Last year, 168 county residents were diagnosed with the virus that causes AIDS — a number that has been fairly constant for nearly two decades.

"Our goals are both ambitious and achievable," said Hennepin County Board Chair Jan Callison. "We can turn the corner on this."

The county hopes to reduce the annual number of new HIV infections by 5 percent by 2018.

One key will be a new effort to contact those who are infected but are not receiving treatment. An estimated 40 percent of the 4,300 county residents with HIV are not receiving care for the infection, despite treatment advances that can suppress the virus and dramatically decrease chances of passing it on to others. That figure includes many who have been diagnosed, as well as many who do not know they are carrying the infection.

"We have powerful tools to prevent the spread of HIV," said Dr. Nicholas Vogenthaler, an HIV physician at Hennepin County Medical Center and clinical director of the county's Red Door clinic.

Under the plan, the county aims to keep 80 percent of those infected with HIV in a treatment program, with 70 percent of those infected having suppressed virus levels.

It also hopes to double the number of people on PrEP, otherwise known as pre-exposure prophylaxis, a daily pill that can reduce the risk of contracting the HIV infection by 92 percent.

"We really want to focus resources on high impact interventions," said Jonathan Hanft, coordinator of the Hennepin County Ryan White program.

About 55 percent of all Minnesotans with HIV live in Hennepin County.

"The more people in care the more cases we can prevent," said Paul Allwood, an assistant commissioner at the Minnesota Health Department. "If you can turn the curve in Hennepin County we believe we can turn the curve statewide."