Cleaning up the arovirus ‘cleaning up bug in California. Here comes a new difficulty

The dreaded norovirus — the “vomiting bug” that often causes stomach flu symptoms — is on the rise again in California, and doctors are warning that new viruses could make more people sick this season.

In LA County, the concentration of Norovirus has already increased in contaminated water, indicating the spread of the disease, the local Department of Health told the Los Angeles Times.

Noovirus rates are increasing throughout California, and the increase is not particularly noticeable in the San Francisco Bay Area and LA, according to the California Department of Health.

And the rate at which norovirus tests confirm infection rose nationally and in the Western US in the week ending Nov. 22, the national inspection rate was 11.69%, up from 8.66% two months earlier. In the West, it was worse: 14.08%, from 9.59%, according to the US Centers for Disease Control and Prevention.

Noovirus is highly contagious, and is America’s leading cause of vomiting and diarrhea, according to the CDC. Outbreaks usually occur in the cooler months between November and April.

Image courtesy of the recent emergence of a new norovirus strain – GII.17. Such developments could lead to more norovirus illnesses than usual, the CDC said.

“If your immune system isn’t used against the next thing, more people get infected,” said Dr. Peter Chin-Hong, an infectious disease specialist at UC San Francisco.

During the winter season of 2024-25, Gii.17 destroyed the previous strain of norovirus, gii.4, which was responsible for the outbreak of Norovirus a decade ago. The progenitor of GII.17 probably came from the underlying structure that caused the outbreak in Romania in 2021, according to CDC scientists.

Gii.17 was attacked in revealing the norovirus surgery at the end of winter and eventually accounted for 75 percent of the outbreaks of the disease nationally.

The emergence of pain combined with the worst year for Norovirus, one that began in early October 2024, broke earlier than in the sky, according to CDC scientists writing in developing infectious diseases.

In the previous three seasons, when Gii.4 was strong, there was norovirus activity, Chin-hong said.

Norovirus can cause a lot of trouble – as many parents well know. A Massachusetts elementary school was forced to cancel all classes Thursday and Friday due to a “high volume of stomach flu,” which was suspected to be caused by Norovirus.

More than 130 students at Roberts Elementary School in Medford, Mass. The company was recognized for making sanitary pads for school classrooms, doorknobs and kitchen appliances.

Some areas in California, however, have not seen significant norovirus activity so far this season. Nationwide, while levels of noonirus in wastewater are increasing, they remain low, the California Department of Health said.

There have been no confirmed norovirus outbreaks reported to the California Department of Health so far this year. Last year, it was 69.

Authorities do not predict how bad norovirus will be in a given year, as most outbreaks are not lab-confirmed, and outbreaks can affect a small or large population.

Between Aug. 1 and November 13, there were 153 publicly reported outbreaks nationwide, according to the CDC. At the same time last year, there were 235.

Cla has not reported an increase in the number of norovirus tests ordered, nor has it seen a significant increase in surprise test numbers. Chin-Hong said he similarly hasn’t seen a big increase at UC San Francisco.

“Things are still stable clinically in California, but I think it’s only a matter of time before we get here,” Chin-hong said.

In a typical year, norovirus causes 2.27 million clinic visits, mostly young children; 465,000 emergency department visits, 109,000 hospitalizations, and 900 deaths, mostly among adults age 65 and older.

People with persistent persistent vomiting, severe diarrhea and shortness of breath may need to seek medical treatment to stay hydrated.

“Children with hypothermia may cry with few or no tears while sleeping and may be unusually sleepy or fussy,” the CDC says. Sports drinks can help dehydrate the body, but over-the-counter dehydrators can help.

Children under five and adults 85 and older are more likely to need to visit an emergency room or clinic because of Norovirus, and should not hesitate to seek care, experts say.

“Everyone is at risk, but the people who worry about it, the ones we see in the hospital, are very young and very old,” said Chin-hong.

Those most at risk are children, because it doesn’t take much to cause serious problems. Newborns are at risk of Necrotizing Enterocolitis, a life-threatening inflammation of the intestines that only new babies have, according to the National Library of Medicine.

While healthy people usually clear the virus in one to three days, infected people may not continue to have diarrhea for a long time “because their immune system cannot neutralize the virus effectively,” said Chin-hong.

The main way people get norovirus is by accidentally drinking water or eating food contaminated with fecal matter, or by touching a contaminated area and putting their fingers in their mouths.

People usually develop symptoms 12 to 48 hours after being exposed to the virus.

Hand sanitizer isn’t effective against Norovirus — which means proper vaccination is essential, experts say.

People should lather their hands with soap and water for at least 20 seconds, including the backs of their hands, between their fingers and under their nails, before drying, the CDC said.

Another useful way to keep track of time is to sing the song “Happy Birthday” from start to finish twice, the CDC says. Chin-Hong says her favorite is the chorus of Kelly Clarkson’s “Since You’ve Been Gone.”

If you live with someone with Norovirus, “It’s best to clean surfaces and objects in contact,” says Chin-hong. Getting dirty is very easy. Even breathing in droplets of saliva from the food eaten by that other person can spread the infection.

Throw away food that may be contaminated with Norovirus, the CDC says. Noroviruses are very heat resistant and can survive temperatures as high as 145 degrees.

Noovirus is so contagious that even 10 virus particles are enough to cause infection. In contrast, it takes thousands of salmonella particles to become sick from this bacterium.

People are highly contagious when they’re sick with Norovirus — but they can still be infected even after they feel better, the CDC says.

The CDC advises staying at home for 48 hours after infection. Some studies have even shown that “you can still spread norovirus for two weeks or more after you feel better,” according to the CDC.

The CDC also recommends washing clothes in hot water.

Besides schools, other places where norovirus can spread quickly are cruise ships, day care centers and prisons, Chin-Hong said.

The latest norovirus outbreak on a cruise ship reported by the CDC is on the AIDADIVA, which sailed on November 10 from Germany. Of the 2,007 passengers on board, 4.8% reported being ill. The outbreak was first reported on Nov. 30 After leaving that month in Portland, England; Halifax, Canada; Boston; New York City; Charleston, SC; and Miami.

According to Cruisemapper, the ship was scheduled to make stops in Puerto Vallarta on Saturday, San Diego on Tuesday, Los Angeles on Tuesday, Santa Barbara on Thursday and San Francisco between December 19-21.