A group of evacuees of the California wildfire has been exposed to an outbreak of norovirus. The virus has broken out at a Butte County shelter, as reported by the Sacramento Bee, but exposure is suspected in a second shelter as well.

In total, 170 people are residing at the shelter where 15 to 20 people are believed to be infected. The sick evacuees have been quarantined away from the healthy ones to prevent further spread.

"They have separate restroom facilities and they are being cared for by public health nurses," said Lisa Almaguer, Butte County Public Health Department spokeswoman.

Even if you have never heard of the virus, chances are you have or will be infected at some point in your life. In fact, the infection is actually quite common around the world.

The United States sees an estimated 19 to 21 million cases of norovirus infection every year according to the Centers for Disease Control and Prevention. It is most likely to sicken people during the months of winter.

"Norovirus is not uncommon, especially this time of year, and it’s especially not uncommon for a shelter situation where you have hundreds of people living in very close quarters," Almaguer added.

Transmission can occur when you touch a sick person directly or come into contact with an object they have touched. In other words, close proximity and the sharing of resources is enough to facilitate the spread of the virus.  

This explains why the virus often strikes cruise ships, summer camps, daycare centers, and nursing homes. You might recall the norovirus also made headlines in 2016 when an outbreak occurred at the Republican National Convention in Cleveland.

Now, what exactly happens when you get sick? Typical symptoms of infection include nausea, diarrhea, vomiting, and body ache. The good news is that it is not dangerous in most cases. If you are a healthy adult, recovery can be expected after one to three days of feeling ill.

"It may last a little longer in children under five years of age or elderly people," noted Robert Atmar, M.D., a professor of infectious diseases at Baylor College of Medicine. For these age groups, there is a higher risk of dehydration and experiencing serious illness.

"For highly compromised patients, such as bone-marrow-transplant recipients or other organ-transplant recipients, it can cause chronic gastroenteritis that can be quite debilitating," Atmar added. "But that’s really an uncommon or infrequent problem. Most people get over it pretty readily."

As always, prioritize good hygiene if you are facing a possible exposure to the virus. Take the time to wash your hands as well as fruits and vegetables before consumption. Make sure to cook foods thoroughly and keep your surroundings and belongings as clean as possible.