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Norovirus is easy to contract, just it can exist hard to recover from. Getty Images
  • A norovirus outbreak shut down an entire Colorado school district right before Thanksgiving.
  • Experts say norovirus is highly contagious and hard to shake.
  • Tips on how to avoid the illness include thoroughly washing hands and staying away from people who are ill.

Dozens of schools in western Colorado are finally reopening this week later on a suspected norovirus outbreak.

On its Facebook page, the Mesa County Valley School District 51 assured the community that its school buildings and buses had been thoroughly disinfected.

Students at the initial schoolhouse began getting sick around November. 14. Then other schools began falling like dominoes.

A week earlier Thanksgiving, officials quickly closed all 46 schools in the district to try to reduce the spread of the outbreak among its 22,000 students.

This is the time of year we hear more about norovirus. And the illness tin be barbarous.

"When you accept norovirus, the very dramatic symptom people have is oft tearing vomiting that hits you pretty suddenly," said Amesh Adalja, Dr., a spokesperson for the Infectious Diseases Order of America and a senior scholar at the Johns Hopkins Academy Middle for Health Security in Baltimore, Maryland.

"You take nausea, vomiting, and diarrhea, and it normally lasts 24 to 48 hours," he told Healthline. "It tin can be a pretty grueling 24 to 48 hours."

The Centers for Affliction Control and Prevention (CDC) reports the virus sickens millions of people each twelvemonth. The very young, older people, and those with other illnesses are nearly vulnerable to severe dehydration.

Each twelvemonth, every bit many as 71,000 people are hospitalized. Between 500 and 800 die.

"What'south very striking about norovirus is that it's very highly infectious. And if you're exposed to information technology, there's a very high likelihood you lot could exist infected by information technology, even if you're in good health," Adalja said.

Experts say that when someone is ill with norovirus, they have large amounts of the virus in them, although it only takes a little to make y'all ill.

"We know that people who have the virus shed information technology in very big numbers in their fecal material. We're talking millions to billions of virus particles in a gram," said Lee-Ann Jaykus, PhD, a professor in the department of food, bioprocessing, and nutrition sciences at N Carolina Land University.

"It probably doesn't take more than than 100 particles to make you ill," she told Healthline.

Jaykus says scientists know the virus is passed from person to person. That happens when an infected person doesn't wash their hands later on using the bathroom.

The surfaces they touch can become contaminated. If the infected person is a food handler, they tin pass the virus onto your nutrient.

They besides know that when an infected person vomits, that surface volition be contaminated.

Merely more than recently, researchers learned that norovirus may also be transmitted in the air from the repeated vomiting.

"A lot of times this is what nosotros call projectile vomiting, very forceful and severe, literally across the room," Jaykus explained. "Some of that vomitus gets aerosolized, and information technology has norovirus in it."

To study how this happens, Jaykus and a team of researchers really congenital a vomiting machine to exam how norovirus spreads. The machine false human airsickness.

The squad used a surrogate virus, which wouldn't make anybody sick. And then they measured the airborne virus particles.

The scientists published the findings of their study in the PLOS 1 journal in 2015.

"You lot tin can discover it. The numbers are non equally high as in fecal material, just information technology'south at that place," Jaykus added. "What happens is some of the virus gets aerosolized, people breathe it in. Information technology hits the mucous membranes, goes into the tummy, and the infection process starts."

And in one case information technology starts spreading through a community, the virus is hard to get rid of.

"This detail virus is extraordinarily resistant to the sanitizers and disinfectants that nosotros usually apply at regulated concentrations and contact times," Jaykus said.

"It'south also incredibly persistent. If I were to put norovirus on a surface in forepart of me right now, it would probably remain capable of causing infection for a calendar month, maybe more," she added.

Jaykus notes in that location'south no norovirus vaccine notwithstanding, although some are being developed.

"The real mode to protect yourself is to wash your hands a lot. If you meet somebody vomiting, go the other way. And if you're on a prowl ship, tell somebody," she said.

The CDC has put together some tips to help yous keep norovirus from spreading:

  • Practice good handwashing for at least 20 seconds. Alcohol-based hand sanitizer solitary won't exercise.
  • Wash your fruits and vegetables. Cook seafood thoroughly.
  • If you're sick, don't cook or care for others for at least ii to three days after you recover.
  • Clean contaminated surfaces showtime, so disinfect them. Use a chlorine bleach solution with a concentration of 1,000 to 5,000 ppm (v to 25 tablespoons of household bleach [5.25 percent] per gallon of h2o) or other disinfectant registered as constructive against norovirus past the Environmental Protection Agency.
  • Launder your laundry thoroughly.