AUGUSTA  — The number of reported cases of hepatitis A in Maine climbed by dozens last year, public health authorities said Thursday.

The Maine Center for Disease Control and Prevention said reported cases of the disease rose from nine in 2018 to 45 last year. A dozen of those cases were linked to a food-borne outbreak in Aroostook County during the summer. Kennebec County also accounted for 12 cases and six were in York County.

The primary means of transmission of the virus in the U.S. is person-to-person, Maine CDC said. Thirty states in the U.S., including neighboring New Hampshire and Vermont, have reported outbreaks of hepatitis A. Maine CDC said the outbreaks are primarily among people who use drugs or are experiencing homelessness.