Island health officials expect to see more flu-like illnesses over the next few weeks following a spike in flu activity in 21 mainland states — especially California, Nevada and Arizona.

Hawaii’s flu “season” lasts year-round but traditionally is linked to wintertime flu outbreaks on the mainland, which are transported to the islands by visitors and returning residents, said Dr. Sarah Park, state epidemiologist and chief of the Disease Outbreak Control Division for the state Health Department.

“We’re hearing that quite a few states are having their flu season and we’re definitely monitoring the situation,” Park said. “When you look at our trends here in Hawaii compared to the mainland, every year we tend to see an uptick in respiratory disease activity a month or so later because we tend to lag behind the mainland.”

Among 21 states dealing with flu symptoms, the U.S. Centers for Disease Control and Prevention says, Arizona, California and Nevada are among the hardest hit, according to the Associated Press.

On its website, the CDC says that “influenza activity is rising in the U.S. at this time. Outpatient visits for influenza-like-illness are above the national baseline. Activity is expected to increase further in the coming weeks.”

“They’re having a not-so-good flu season,” Park said. “It’ll be heading this way at some point, probably in a month or so.”

Locally, the number of island patients complaining of flu-like symptoms in the last week of 2016 increased nearly 4 percent from the week before.

And positive tests for the influenza virus across the islands rose more than 29 percent from the week before.

Park continued to urge people to get a flu vaccine and, just as important, practice good hygiene and stay home if sick.

“Don’t go to work, don’t go to school,” Park said. “People are patting themselves on the back for not going to school or work when they have flu-like symptoms, then they run an errand. So don’t go shopping either, because you’re just sharing your germs. When we say stay home when you’re sick, stay home.”

“In Hawaii,” Park said, “we attract travelers from all over the world. So diseases come to us and they can spread if we don’t do our part to protect our community by washing hands and staying home. And get vaccinated. If we can all do it as a community together, maybe we won’t see as heavy activity as they’re seeing on the mainland.”