MARIN COUNTY, Calif. (KRON) — Norovirus—often referred to as the stomach flu or the stomach bug—is very contagious is at a seasonal high nationwide, according to the Center for Disease Control.

Now, local officials are now warning of an upcoming outbreak.

Outbreaks of the virus are common, especially during this time of year. Norovirus is highly contagious and spreads quickly from person to person through contaminated foods, surface, hands or water and can be transmitted for days—even after a person is feeling better.

The CDC says we’re at a 13 percent positivity rate in the western region.

Ross Valley School District is asking parents to keep kids home if they see symptoms.

“There is zero cases in the Ross Valley School District,” Marci Trahan, superintendent of Ross Valley School District told KRON4. “The county health department has seen an uptick of potential virus of the Norovirus in the wastewater and so they were just letting us know when with the midwinter break coming up, they just wanted us to share the information with our families and staff.”

Norovirus outbreaks on the rise in Contra Costa County

The biggest symptoms are vomiting and diarrhea. It can be accompanied by nausea, abdominal cramps, body aches, headaches and low-grade fevers.

Most are better within one to three days, but the illness can last up to week.

Ross Valley School District says if your child has vomiting or diarrhea, they must stay home for 24 hours. And if they do test positive for the virus, they need stay home for 2 days after their last symptom.

Officials say to remember to wash your hands, rinse fruits and vegetables, cook shellfish thoroughly and avoid preparing food for others if you are sick.