Norovirus is nearly impossible to stop

In a very specific and mostly benign way, it’s starting to look a lot like Spring 2020; disinfection. back.

“Bleach is my friend right now,” said Annette Cameron, a pediatrician at Yale School of Medicine who spent the first half of this week spraying and pouring the powerful chemical all over the house. It’s one of the few tools she has to fight norovirus, the nasty intestinal pathogen her 15-year-old son was recently shedding.

Right now, a group of people in the Northern Hemisphere are in a similar predicament. In recent weeks, norovirus has broken out in several countries, including the United Kingdom, Canada and the United States. Last week, Britain’s Health Safety Agency announced that laboratory reports of the virus had reached a level 66 percent higher than is typical for this time of year. Britons aged 65 and over have been hit particularly hard, falling ill at a rate “not seen for more than a decade”.

Americans themselves may be in for a rough ride, Caitlin Rivers, an infectious disease epidemiologist at Johns Hopkins University, told me, given how closely US epidemiological patterns tend to follow Britain’s. right now,” said Nihal Altan-Bonet, a norovirus researcher at the National Institutes of Health. In his own practice, Cameron saw a steady increase in the incidence of vomiting and diarrhea among his patients. (Other pathogens can also cause gastrointestinal symptoms, but norovirus is the most common cause of foodborne illness in the United States.)

To be clear, this is more of a nuisance than a public health crisis. In most people, norovirus causes, at most, a few miserable days of GI discomfort, which can include vomiting, diarrhea, and fever, and then resolves on its own; The key is to stay hydrated and avoid spreading it to vulnerable people: young children, the elderly, the immunocompromised. The US records fewer than 1,000 deaths per year out of millions of documented cases. In other high-income countries, severe consequences are also very rare, although the virus is much more deadly in parts of the world with limited access to sanitation and drinking water.

However, fighting norovirus is not easy, as many parents can attest. The trigger, which forces the body to remove infectious material from both ends of the digestive tract, is seriously gross and disappointingly resistant. Even the old COVID standby, hand sanitizer, doesn’t work against it — the virus is encased in a tough protein shell that makes it insensitive to alcohol. Some have estimated that ingesting 18 infectious units of the virus could be enough to make someone sick, “and typically what’s shed is in the billions,” said Megan Baldridge, a virologist at Washington University in St. Louis and immunologist. In an extreme case, one gram of feces, which is about the size of a jelly bean, can contain 5.5 billion infectious doses, enough to flush the entire population of Eurasia.

Unlike the flu and RSV, two other pathogens that have reemerged in recent months, norovirus primarily targets the gut and spreads particularly well when people ingest viral particles that have been shed in someone else’s vomit or feces. (Despite its “stomach flu” nickname, norovirus is not a flu virus.) But direct contact with these substances or food or water contaminated with them may not even be necessary; Sometimes people vomit so hard that the virus becomes aerosolized; Toilets, especially those without lids, can send plumes of infection from hell like an air dragon. And Altan-Bonnet’s team found that saliva may be an underappreciated reservoir for norovirus, at least in lab animals. If saliva detection involves people, talking, singing and laughing nearby can also be risky.

Once released into the environment, norovirus particles can remain on surfaces for several days, making frequent hand washing and surface disinfection key measures to prevent spread, said Ibukun Kalu, a pediatric infectious disease specialist at Duke University. Handshakes and shared meals tend to be disgusting during an outbreak, as are frequently touched items such as utensils, doorknobs, and telephones. A 2012 study identified a woven plastic grocery bag as the source of a small flare-up among a group of teenage soccer players. the bag had just been sitting in the bathroom one of the girls was using when she got sick the night before.

Once the chain of norovirus transmission starts, it can be very difficult to break. The virus can be spread before symptoms start and then for more than a week after they disappear. To make matters worse, immunity to the virus tends to be short-lived, lasting only a few months, even against a genetically identical strain, Baldridge said.

Day care facilities, cruise ships, schools, restaurants, military training camps, prisons, and long-term care facilities can be common places for norovirus to spread. “I’ve done research with the Navy, and it just goes like wildfire,” often sickening more than half the people on the tightly packed ships, said Robert Frank, director of the Vaccine Research Center at Cincinnati Children’s Hospital. Households are also very susceptible to spread. Once the virus arrives, the whole family is almost certain to be infected. Baldridge, who has two young children, told me her family has dealt with at least four bouts of norovirus in the past few years.

(Pause for irony: Despite the fact that norovirus is contagious, scientists didn’t succeed in developing it in labs until just a few years ago, after nearly half a century of research. When researchers design trials to test, say, new vaccines, they still have to give volunteers norovirus, which extracted from the patient’s stool, a startling practice that has been around for over 50 years.)

The spread of norovirus is not necessarily a foregone conclusion. Some people are lucky. for example, approximately 20 percent of the European population is genetically resistant to common norovirus strains. “Then you can hope,” said Frank. For the rest of us, it’s about hygiene. Altan-Bonnet recommends diligent hand washing as well as wearing a mask to protect against the droplet-borne virus. Sick people should isolate themselves if they can. “And keep your saliva to yourself,” he told me.

Rivers and Cameron have both been able to stop the virus in their homes in the past; Cameron may be out again this week. The family strictly washed their hands with hot water and soap, wore disposable gloves when touching common surfaces, and took advantage of the virus’s sensitivity to harsh chemicals and heat. When her son fell to the floor, Cameron sprayed it with bleach. when she vomited on her blanket, she blasted it twice on the sanitizer in the washing machine, then put it through the dryer on super high heat. Now days after their son’s illness ended, Cameron and her husband appear to have escaped unscathed.

Norovirus is nothing new, and this won’t be the last time it strikes. In many ways, “it’s back to basics,” says Samina Bumbra, medical director of infection prevention at Riley Children’s Hospital. After three years of COVID, the world has learned to think of infections in terms of the respiratory tract. “We need to recalculate,” Bumbra told me, “and remember there are other things.”

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