BISMARCK, N.D. (AP) - North Dakota has more than 500 confirmed cases of the flu, state health officials say.

Health officials said the the 518 confirmed cases is up from the 256 reported last week.

Michelle Feist, the state influenza surveillance coordinator, said it's the time of the year when the number of cases picks up, and it might continue for weeks.

"It's never too late to get vaccinated, even if we're experiencing a peak level of activity, it's still beneficial to get the vaccine. The season does run from October through May," Feist said. "Even if you make it through the peak season, there is still time for the virus to be circulated," Fiest said.

Cass County leads the state with 109 confirmed cases, followed by Stutsman County with 65. Stark County has 47 cases and Burleigh and Grand Forks counties, each reported 44 reported cases.

More than 2,100 flu cases were confirmed in North Dakota during the last flu season, which peaked in March.