Northern Westchester Hospital Center has confirmed five cases of hepatitis C among more than 1,200 former surgery patients who were encouraged to get screened.

Officials say former hospital technician Kristen Diane Parker has hepatitis C and admitted to stealing syringes, injecting herself and putting the equipment back for patient use while she worked at a Colorado hospital. It is unclear if Parker also used syringes while working at Northern Westchester from October 2007 to February 2008.

Hospital officials say at least three of the five people who tested positive had hepatitis C prior to when Parker worked at the hospital. They say it is still unclear if she spread the disease to any former patients.