Contagious Stomach Bug Spreads Across California

CALIFORNIA — If it seems like everyone's catching the "stomach bug" lately, chances are it's probably norovirus: Cases of the virus have spiked in recent weeks and continue to climb in California and the western U.S., according to the Centers for Disease Control and Prevention.

Norovirus, often called food poisoning or the stomach flu, is a contagious virus that causes vomiting and diarrhea. It spreads easily from person to person and from contaminated food and surfaces. Hand sanitizer is usually ineffective in killing the virus, according to the California Department of Public Health.

After gradually increasing late last year, the three-week average positivity rate for norovirus tests in the Western U.S. have largely held steady at around 12 percent since the last week in December, according to CDC Data released Thursday.

Last year, the three-week average followed a similar pattern before peaking at the end of April, when it nearly reached 17 percent.

Other parts of the country have lower rates, including around 10 percent in the Midwest and 9.5 percent in the South. In the Northeast, the three-week average reached 13.9 percent in recent weeks.

California health officials say norovirus outbreaks are common and can happen at any time, but most often occur between November and April.

Earlier this year, a norovirus outbreak linked to raw oysters sickened more than 100 people across Southern California. The FDA narrowed the oysters down to batches caught in Baja California, Mexico, but the outbreak prompted health officials in California to warn people to avoid eating any oysters until the outbreak was contained.

Norovirus can contaminate food that's grown or washed in contaminated water or if it's prepared by someone who is infected with the virus, state health officials said. It's the No. 1 cause of foodborne illness in the U.S., according to the CDC.

Additionally, it spreads very easily from person to person — through direct contact between two people — and can survive for weeks on surfaces and objects, according to health officials.

Outbreaks frequently occur in healthcare settings, schools, daycares and cruise ships, health officials said.

State health officials offered these tips to avoid the spread of norovirus:

• Practice good hand washing techniques using soap and water — hand sanitizers are usually not effective against norovirus.
• Thoroughly wash fruits and vegetables.
• Cook shellfish thoroughly.
• If you're sick, stay home: Isolate for at least two days after you feel better.
• Do not prepare food or care for others when you're sick with norovirus or have diarrhea
• Clean and disinfect contaminated surfaces or objects with a bleach solution in order to kill norovirus