Four residents of the state veterans home in Minneapolis died last weekend and more than a dozen employees reportedly called in sick from a suspected outbreak or norovirus, the Minneapolis Star Tribune reported.
The veterans' home said it put a temporary hold on any new admissions.
Norovirus causes vomiting, diarrhea and cramps and each year causes up to 70,000 hospitalizations and 800 deaths, but it is not related to influenza, which is an upper respiratory virus.
Last week, 125 veterans and a couple of dozen veteran's home staff were sickened with what was reported as norovirus, while a veterans facility in Boise, Idaho, was quarantined and norovirus was confirmed, the Star Tribune reported.
WRC-TV in Washington, D.C. reported an Alexandria, Va., elementary school was closed Friday, after more than 200 students and 30 staff fell ill due to possible norovirus. An Asheville, N.C., elementary school reported more than 150 students and several staff reported with symptoms typical of stomach flu.
All school districts and daycare facilities in Muskegon County in Michigan were sent a letter from the health department Wednesday warning students and employees who suffered nausea, vomiting and diarrhea must remain out of school at least 48 hours after their symptoms subsided, the Muskegon Chronicle reported. The week before more than 460 students in county schools and day cares were suspected to have norovirus.
More than 200 patients and staff were sickened with suspected norovirus at the Southern Oregon Rehabilitation Center and Clinics based in White City, Ore., but the virus seems to be on the wane. However, 17 people were treated in a hospital for dehydration.
Since it only takes a few particles of the norovirus to infect someone, CNN asked the U.S. Navy how it managed to keep its staff healthy.
The U.S. Navy told CNN it managed to prevent any major outbreaks of contagious diseases because it takes any outbreak of sickness seriously.
Capt. Jim McGovern, commanding officer on the USS Iwo Jima, said aboard his ship docked in Norfolk, Va., any crew member who feels ill must report to sick bay and be isolated from others to keep it from spreading if it is contagious.
Even if a sailor doesn't want to go be treated, the supervisor will make him or her be isolated if they have a contagious disease and make sure they do not have contact with the general population of the ship and stay away from where food is served, McGovern said.
Members of the Navy are also required to help keep the ship clean every day.
In addition, kitchens are constantly cleaned, inspected and tested to prevent foodborne illnesses several times a day, Jakeila Owens, Iwo Jima culinary specialist, told CNN.
McGovern said about 3,200 sailors and marines fill the amphibious assault ship at deployment and even a small outbreak of sickness would "devastate our operational capability."