Norovirus

Norovirus, also known as Norwalk virus and sometimes referred to as the winter vomiting disease, is the most common cause of gastroenteritis.^[1][6] Infection is characterized by non-bloody diarrhea, vomiting, and stomach pain.^[2][3] Fever or headaches may also occur.^[2] Symptoms usually develop 12 to 48 hours after being exposed, and recovery typically occurs within one to three days.^[2] Complications are uncommon, but may include dehydration, especially in the young, the old, and those with other health problems.^[2]

The virus is usually spread by the fecal–oral route.^[3] This may be through contaminated food or water or person-to-person contact.^[3] It may also spread via contaminated surfaces or through air from the vomit of an infected person.^[3] Risk factors include unsanitary food preparation and sharing close quarters.^[3] Diagnosis is generally based on symptoms.^[3] Confirmatory testing is not usually available but may be performed by public health agencies during outbreaks.^[3]

Prevention involves proper hand washing and disinfection of contaminated surfaces.^[4] There is no vaccine or specific treatment for norovirus.^[4][5] Management involves supportive care such as drinking sufficient fluids or intravenous fluids.^[5] Oral rehydration solutions are the preferred fluids to drink, although other drinks without caffeine or alcohol can help.^[5] Hand sanitizers based on alcohols tend to be ineffective against noroviruses due to their being non-enveloped, although some virus genotypes are more susceptible.^[8]

Norovirus results in about 685 million cases of disease and 200,000 deaths globally a year.^[6][7] It is common both in the developed and developing world.^[3][9] Those under the age of five are most often affected, and in this group it results in about 50,000 deaths in the developing world.^[6] Norovirus infections occur more commonly during winter months.^[6] It often occurs in outbreaks, especially among those living in close quarters.^[3] In the United States, it is the cause of about half of all foodborne disease outbreaks.^[3] The virus is named after the city of Norwalk, Ohio, in the United States, where an outbreak occurred in 1968.^[10]