The virus, called the norovirus and also known as the “cruise ship illness” occurs mainly in areas where large groups of people live together. It can cause nausea, vomiting, diarrhea, a low fever, chills, headache, muscle aches and fatigue. It is not related to influenza and doesn’t carry the respiratory symptoms of the seasonal flu.

Symptoms usually last a day or two, but people can remain contagious for a week or more. The virus is spread through the fecal-oral route, such as fecally contaminated food or water, touching infected surfaces or having direct contact with an infected person, according to the Centers for Disease Control and Prevention.

“It’s very common,” said Alvina Chu, of the state health department’s division of outbreak investigation, adding there is usually an increase in the winter.

The city health department has confirmed one outbreak so far this year where 11 people became ill at a child and adolescent group facility, Herrera said. Three other outbreaks at nursing homes and an assisted living facility, are also possible, but haven’t been confirmed.

“We typically see it in winter months,” she said.

The Anne Arundel County Health Department also received reports of the virus this time of year, but there have been no reports to date, said spokeswoman Elin Jones.

There also haven’t been any outbreaks in Howard County, but there may be cases that aren’t reported because most patients don’t have samples tested to confirm the cause, said Health Officer Dr. Peter Beilenson.

“I am sure we have norovirus,” Beilenson said, “But it’s one of those viral infections of this time of year.”

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