Norwalk Virus Outbreak

Norovirus (previously called “Norwalk-like viruses”) In My Town ...

Norovirus (previously called “Norwalk-like viruses”)[1], is an RNA virus of the Caliciviridae taxonomic family. The virus causes approximately 90% of epidemic non-bacterial outbreaks of gastroenteritis around the world,[2][3] and is responsible for 50% of all foodborne outbreaks of gastroenteritis in the US.[4] Norovirus affects people of all ages. The viruses are transmitted by faecally contaminated food or water and by person-to-person contact.[5]

After infection, immunity to norovirus is usually incomplete and temporary.[6] There is an inherited predisposition to infection, and individuals with blood type O are more often infected,[2][7] while blood types B and AB can confer partial protection against symptomatic infection.[8][9]

Outbreaks of norovirus disease often occur in closed or semi-closed communities, such as long-term care facilities, hospitals, prisons, dormitories, and cruise ships where once the virus has been introduced, the infection spreads very rapidly by either person-to-person transmission or through contaminated food.[10] Many norovirus outbreaks have been traced to food that was handled by one infected person.[11]

Norovirus is rapidly inactivated by chlorine-based disinfectants, but because the virus particle does not have a lipid envelope, it is less susceptible to alcohols and detergents.[12]

There are different genogroups of norovirus and the majority of noroviruses that infect humans are classified into genogroup G1 and G2.[13]

History The norovirus was originally called the Norwalk Virus. The name was shortened to the norovirus after receiving national attention for being identified in multiple cruise ship outbreaks. The Norwalk Virus was named after Norwalk, Ohio, where an outbreak of acute gastroenteritis occurred among a vast majority of children at Bronson Elementary School in November 1968. In 1972, immune electron microscopy on stored stool samples identified a virus, which was given the name Norwalk virus. Numerous outbreaks with similar symptoms have been reported since. The cloning and sequencing of the Norwalk virus genome showed that these viruses have a genomic organization consistent with viruses belonging to the family Caliciviridae.[14] The name norovirus (Norovirus for the genus) was approved by the International Committee on Taxonomy of Viruses in 2002. [15]

Common names of the illness caused by noroviruses are winter vomiting disease, viral gastroenteritis and acute non-bacterial gastroenteritis[5], also colloquially known as “stomach flu” — a broad name that can also refer to gastric inflammation caused by other viruses and bacteria.

Viral infections of humans, epidemiology and control

Viruses and human disease

Fields virology

International handbook of foodborne pathogens

Virology