They call it the winter vomiting disease, and California officials are warning that it’s on the rise.

Already, the state has confirmed 32 outbreaks since Oct. 1 — far more than the nine cases reported last year at this time — and health officials are urging Californians to wash their hands frequently to guard against infection.

Caused by the highly contagious pathogen known as norovirus, the illness spreads rapidly in closed and crowded environments, such as hospitals, nursing homes, day-care centers, schools, cruise ships and restaurants.

It typically causes abdominal pain, nausea, diarrhea and vomiting — conditions that can be very serious for young children and older adults.


See more of our top stories on Facebook >>

“One of the most important things you can do to avoid norovirus and other illnesses this holiday season is to wash your hands frequently with soap and running water for at least 20 seconds,” said Karen Smith, California Department of Public Health director and state public health officer. “This is especially important after using the bathroom, changing diapers, and before preparing or eating food.”

The virus can spread through direct contact with an infected person; by consuming infected foods or liquids; or by touching a contaminated surface and then touching one’s mouth, health officials say.

Dr. William Schaffner, infectious diseases specialist at Vanderbilt University School of Medicine, said that once viral particles enter the body, they latch on to the mucosal cells that line the intestines and disrupt their ability to absorb vital fluids.


“And voom, then out it comes as diarrhea,” Schaffner said. “It causes an extremely unpleasant illness.”

In the recent California outbreaks, the majority of cases have occurred at nursing homes and other long-term care facilities, with the remainder affecting schools and event centers, health officials said. Symptoms usually begin 12 to 48 hours after exposure and last one to three days.

“It’s very readily transmissible,” Schaffner said. “That also contributes to the nursing home outbreaks, because those people are all confined and so they get repeated exposure to people who are sick or who are going to be sick or have recovered from sickness and are still capable of transmitting the virus.”

Schaffner speculated that this year’s uptick in documented cases might be the result of greater awareness.


“I will bet they’re looking much harder for it and therefore just defining these outbreaks better,” Schaffner said. “If a lot of these are indeed nursing home outbreaks, that’s probably increased awareness by nursing home physicians and nursing home administrators and increased readiness to call on public health for outbreak investigations.”

In the United States, norovirus is the most common cause of gastroenteritis and is responsible for about 20 million illnesses each year. Between 570 and 800 deaths are reported annually, health officials said.

The illness occurs more frequently in the winter and is so distinctively associated with vomiting that it was given the nickname “winter vomiting disease,” Schaffner said. However, it has also been called the “cruise ship virus.”

One of California’s first outbreaks this year occurred in May, when several patrons and employees at the Sky Room, an upscale Long Beach restaurant, fell ill. The business closed for four days to sanitize the restaurant and bar.


The disease struck again in August at a Ventura County Chipotle restaurant, where an outbreak was believed responsible for sickening more than 60 customers. Managers were forced to shut down the restaurant, throw out the remaining food and disinfect all surfaces.

Most recently, a norovirus outbreak may have sickened as many at 50 students at Chapman University. The gastrointestinal illness was first reported Dec. 2 by several students and grew rapidly.

The Orange County Health Care Agency investigated the cause of the outbreak and one source could have been the school’s only cafeteria, the agency said. The cafeteria was closed and disinfected, the campus was swept down, and the bathrooms and common areas were also cleaned.

In addition to washing hands after every bathroom visit, health officials urged Californians to wash fruits and vegetables before eating them. Officials also said residents should clean and disinfect food preparation equipment and surfaces, and thoroughly cook all meats, fish and poultry.


Unfortunately, one means of trying to prevent illness that many Californians have adopted in recent years will not fend off the virus.

“Hand sanitizers,” Smith said, “are not effective against norovirus.”

Follow me on Twitter @brittny_mejia

brittny.mejia@latimes.com


ALSO

Winter weather could complicate motorists’ holiday travel

San Diego police say 400-pound bearded woman stabbed man

Police search for clues after gunmen fire on undercover officers