After the holiday season and an uptick in travel, California is seeing a rise in respiratory illnesses, prompting health experts to talk of a potential “quad-demic.” The term refers to the simultaneous spread of four major viruses: COVID-19,

Norovirus, which causes sudden vomiting and diarrhea, has seen a surge in recent weeks. It spreads quickly and can run through an entire family.

Flu season is here in California, but other illnesses are in full swing in the Golden State. Here are the symptoms and how long you're contagious.

Dr. Marlene Wolfe, the Co-principal investigator with WastewaterSCAN said there is increased detection of norovirus at California's wastewater testing sites.

Many respiratory viruses, including Influenza, RSV and COVID-19, can cause cold-like symptoms,” state health officials said.

Norovirus is a very contagious virus causing vomiting and diarrhea. It's not related to the flu despite being commonly referred to as 'stomach flu.'

Although the number of norovirus outbreaks was slightly higher across the nation based on more than a dozen states participating in NoroSTAT, California’s total number is less than last year so fae.

The Pasadena Public Health Department said they will support the American Red Cross and onsite medical teams following a Norovirus outbreak at the city's evacuation center.

Three people have tested positive for norovirus amid a cluster of 28, the Pasadena Public Health Department said on Friday.

An infectious-disease doctor said that as more people gathered for the holidays, they created prime conditions for norovirus to spread.

Norovirus, commonly known as the “stomach bug” or “winter vomiting disease,” causes acute gastroenteritis, or an inflammation of the stomach or intestines. The stubborn virus is one of the most common causes of vomiting, diarrhea and stomach cramps, according to the California Department of Public Health.