A rise in HIV cases in King County has prompted a warning from the public health department.

On Thursday afternoon, Seattle and King County Public Health Officer Dr. Jeff Duchin held a press conference concerning a possible outbreak. He reported that since February, eight people in North Seattle have contracted HIV.

The eight people are heterosexual and homeless, have used injected drugs, and a few have had sex for either drugs or money.

This increases the number of HIV cases among heterosexuals who inject drugs in King County to 19. Last year at this time, it was 10.

Duchin said this is concerning because HIV is not common among heterosexuals who used injectable drugs. Since this population does not have good access to health care, clean needles and condoms, it means there is a big risk of the virus spreading.

"If HIV begins to spread in a new population among persons who inject drugs, who do not have other risk factors for HIV, there can be a large outbreak potentially," said Duchin.

"There's a large number of susceptible people who are practicing risky behaviors that can promote the spread of HIV. And up to now, HIV has not really been circulating in that community."

Duchin says those eight people are now receiving treatment and are being monitored.

In a statement, the Public Health Department reports it is increasing its outreach and testing programs, and making more needles accessible.

The department should be releasing more information next week as it continues to investigate the outbreak.