POUGHKEEPSIE – The norovirus infection, similar to that which people contract on cruise ships, has struck Dutchess County, hitting people by the hundreds with a 24 hour stomach flu, County Health Commissioner Michael Caldwell said Thursday.

The exact cause is unknown, but he said with people swimming in lakes and at summer camps, cleanliness is the order of the day to prevent it from spreading even more.

“This is a pretty virulent bug, nobody has been hospitalized and nobody is very ill,” he said. “It is something that we would prefer to prevent.”

Norovirus is very contagious and persons can become infected by having direct contact with an ill person, eating or drinking contaminated food or liquids, and/or by touching contaminated surfaces and then placing their hand in their mouth.

Symptoms of the bug include vomiting and/or diarrhea, nausea, malaise or stomach cramps.

The Health Department recommends washing hands thoroughly and frequently, especially after going to the bathroom and before handing food; using gloves when cleaning diarrhea or vomit, and wearing masks when cleaning up vomit. People with symptoms should not attend school or handle food, do not share personal items, avoid drinking untested water and cook shellfish thoroughly before eating.