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Acute gastroenteritis outbreak in Norwalk, Ohio
October 1968: An outbreak of acute gastroenteritis takes place in an elementary
school in Norwalk, Ohio. During a 2-day period, 50% of the students and
teachers (116/232) developed a gastrointestinal illness, and there was
a secondary attack rate of 32% among contacts of primary cases. Lab
tests did not reveal an etiological agent.
LID searches for viral agent of gastroenteritis
1969-1972: The Laboratory of Infectious Diseases (LID) at the National Institutes
of Health (NIH) embarks on an intense search for a non-bacterial
(viral) etiological agent of acute gastroenteritis.
Norwalk Virus is discovered
June 1972: The 27-nm virus-like particle is discovered by the use of immune
electron microscopy, from an infectious stool filtrate derived from an
outbreak of gastroenteritis in an elementary school in Norwalk, Ohio.
It is described as a “small round-structured virus” (SRSV).
CDC creates Vessel Sanitation Program
1975: the CDC creates the Vessel Sanitation Program (VSP) to minimize the
risk for gastrointestinal disease among passengers and crew aboard
ships by assisting the cruise ship industry in developing and
implementing comprehensive environmental health programs. Today, the
VSP is an important organization in the surveillance and prevention of
norovirus outbreaks.
Sapporo virus first detected
October 1977: Sapporo virus is first detected during a gastroenteritis outbreak in a home for infants in Sapporo, Japan. It is distinguished by its typical surface morphology.
Hepatitis E virus added to Caliciviridae
1988: Hepatitis E virus is only provisionally classified as a member of Caliciviridae. The virus was first isolated in the 1950's.
Norovirus classified in Caliciviridae
1990: The norovirus genome is finally cloned and sequenced, allowing its classification in the Caliciviridae family.
Sapovirus genus identified as genetically distinct
1992: Sapoviruses are officially identified as genetically distinct from noroviruses.
This is accomplished through the cloning and initial genetic
characterization of a genome of human calicivirus with “classical”
morphology and comparison with the cloned genome of Sapporo/82/Japan.
International outbreak of single Norovirus strain
1995-1996: “95/96-US” strain of ‘Norwalk-like viruses” cause 60 outbreaks in geographically distant locations within the US and are identified in an additional 7 countries on 5 continents during the same period.
Hepatitis E virus removed from Caliciviridae
1998: Hepatitis E is removed from Caliciviridae family, after genomic sequencing reveals phylogenetic differences in the non-structural regions of the virus genome.
Major norovirus outbreak on Mediterranean cruise
November 2003: Spanish authorities close the border with the British colony of Gibraltar before the arrival of a virus-stricken cruise ship carrying some 2,000 passengers. More than 400 passengers on the ship fell ill with a norovirus after the ship left Southampton, England, for a Mediterranean voyage on Oct. 20.
Major norovirus outbreak hits United Kingdom
Winter 2007: In the largest norovirus outbreak of the UK in five years, thousands contract viral infection. 100,000 people contract virus per week.