Norovirus is very common and is a kind of virus that causes "stomach flu" in humans. You most likely have been infected with it sometime in your life. The "stomach flu" is usually indicated by nausea, vomiting and diarrhea and is similar to the symptoms of food poisoning.
Norovirus has a very short incubation period of twelve hours to two days after the first exposure. It spreads from person to person with ease. The patient is contagious from the moment they start feeling ill until up to two weeks from the onset of symptoms. An important part of preventing new cases is for the infected person and their care givers to wash or sanitize their hands regularly.
Touching a surface that has been contaminated, such as a door handle or elevator button and then touching any of your mucus membranes will transfer this virus. Sharing drinks or utensils with an infected person is another common method of transfer. Sewage pipe damage resulting in contaminated drinking water is another way Norovirus can be transferred.
You may experience a mild fever. This kind of illness usually does not last very long and patients are only afflicted for one to two days. Dehydration can become a problem if the patient cannot retain enough fluids to replace the ones they are losing through vomiting and diarrhea. If the patient becomes dehydrated you may want to seek medical attention.
If you have Norovirus you should not go to school or work while you are exhibiting symptoms, as this virus is highly contagious. It cannot be treated with antibiotics and there is no vaccine yet developed that works against it. Cases have occasionally stemmed from under cooked oysters.