Norovirus In CA: 5 Things To Know

CALIFORNIA — Health authorities urged Californians to avoid eating raw or undercooked oysters from British Columbia, Canada, this week after a spate of norovirus cases.

COVID-19 cases continued to fall, but norovirus cases have ticked up, according to data from the Centers for Disease Control and Prevention.

The dreaded norovirus is often referred to as a "stomach flu," but officials said it is not related to influenza. The sticky bug causes severe vomiting and diarrhea and can affect anyone of any age.

From August 2021 to March 10, 2022, at least 448 known cases of norovirus were reported in the U.S., according to the CDC.

Norovirus is the most common cause of gastroenteritis in the nation. It triggers an estimated 19 million to 21 million cases of illness every year. About 56,000 to 71,000 people were hospitalized with the virus each year, and 570 to 800 people died from the virus every year in the U.S., according to the CDC.

Here's what's going on in the Golden State.

1. There Are Dozens Of Cases In California

Statewide, at least 34 people became ill after eating oysters at nine restaurants throughout the state, the California Department of Public Health reported this week. Outbreaks were also reported in other states.

Canada reported 279 cases of norovirus and similar illnesses linked to consumption of British Columbia oysters.

"Although multiple oyster recalls associated with British Columbia have been posted by CDPH, additional illness has been reported in California residents linked to oysters from British Columbia that have not been recalled," officials wrote in a statement. "CDPH staff continue to investigate and share updates with state and federal partners, which may lead to recall of more oysters."

2. It's Highly Contagious

It is strongly advised for residents to avoid eating raw or undercooked oysters sourced from British Columbia, and it may also be wise to avoid those who are sick.

Norovirus is highly contagious and can be spread easily from person to person or through contaminated surfaces.

The bug can spread rapidly because of the billions of microscopic virus particles that can remain on surfaces and in food or water. It takes only a few of the particles to infect someone.

People can contract norovirus in the following instances, according to the state Department of Public Health.

• Coming into contact with a sick person while caring for them, sharing food or eating utensils or changing diapers of a sick child.
• Eating food or drinking liquid that contains the virus, such as food touched by an ill person or undercooked shellfish from contaminated waters.
• Touching contaminated surfaces or objects and then touching one's mouth or food before washing hands.
• Sharing toilet facilities with a sick person.
• Cleaning up vomit or diarrhea from an infected person without protective gear, such as gloves, masks and gowns.

Cases could also be rising because of lifted mask mandates, said Dr. Robert Atmar, a professor of medicine and infectious disease expert at Baylor College of Medicine in Houston, according to NBC News.

"The concentration of virus in stool samples is pretty high, so it doesn’t take much microscopic contamination to infect people," Atmar told NBC News.

3. It's Foodborne Illness

Norovirus can spread easily from person to person, but outbreaks typically arise from the consumption of undercooked shellfish and oysters.

"Avoid eating raw and undercooked shellfish, including oysters, to reduce your risk of illness," Dr. Tomás J. Aragón, state public health officer and director of the state public health department, said in a statement.

"If you do eat shellfish, cook it until it reaches an internal temperature of at least 145°F. Quick steaming isn't sufficient to kill norovirus," he advised.

4. Symptoms Usually Arise Quickly

Symptoms of the illness typically appear 12 to 48 hours after exposure to a sick person or after consuming raw or undercooked shellfish, including oysters, according to the department.

Common symptoms include vomiting, diarrhea, nausea and stomach cramps. Those who develop symptoms were advised to reach out to health care providers.

Typically, someone is contagious as soon as she starts feeling ill and can remain contagious until a few days after symptoms let up. An ill person may also be contagious for two weeks or longer after feeling better, according to the state.

For more information see department's norovirus webpage.

5. How To Prevent Infection

The best way to avoid coming down with the stomach bug is to keep up good hand hygiene.

Californians should wash their hands with soap and water for about 20 seconds, especially before preparing food.

Surfaces should also be decontaminated often with diluted bleach.

A person can also contract novovirus more than once since there are many strains and mutations of the virus, according to the public health department.