An outbreak of Norwalk-like virus gastroenteritis in an aged-care residential hostel.

Norwalk-like viruses are members of the calicivirus family, first discovered in 1972 following an outbreak of gastroenteritis in Norwalk, Ohio, and more recently renamed Norovirus. They are a common cause of outbreaks of gastroenteritis in institutions throughout the winter months. The faecal–oral route is the primary method of transmission; however, airborne spread from vomitus and fomites (objects or places where infection survives apart from the host’s body) has also been reported. The infection typically presents with acute projectile vomiting, watery diarrhoea, and nausea. These symptoms usually resolve within 72 hours. High concentrations of Norwalk-like virus (NLV) are found in infected faeces and vomitus, and as only small amounts of virus are required to cause infection, this contributes to the ease of transmission.