Norovirus, sometimes referred to as the winter vomiting bug in the UK and Ireland, is the most common cause of viral gastroenteritis in humans. It affects people of all ages. The virus is transmitted by fecally contaminated food or water, by person-to-person contact, and via aerosolization of vomited virus and subsequent contamination of surfaces. Annually, norovirus is associated with 906,000 outpatient visits in industrialized countries, with 64,200 inpatient hospitalizations. In developing countries, it is associated with 1.1 million hospitalizations, with an estimated 218,000 deaths. Norovirus infection is characterized by nausea, vomiting, watery diarrhea, abdominal pain, and in some cases, loss of taste. A person usually develops symptoms of gastroenteritis 12 to 48 hours after being exposed to norovirus. General lethargy, weakness, muscle aches, headaches, and low-grade fevers may occur. The disease is usually self-limiting, and severe illness is rare. Although having norovirus can be unpleasant, it is not usually dangerous and most who contract it make a full recovery within two to three days. On surfaces, norovirus is rapidly inactivated by either sufficient heating or by chlorine-based disinfectants and polyquaternary amines, but the virus is less susceptible to alcohols and detergents.