Noroviruses are a type of single-stranded, positive-sense RNA viruses belonging to the family Caliciviridae.
They are highly contagious viruses whose main routes of transmission are: person-to-person contact and through contaminated food/water (in the U.S. is estimated that they account for 50% of gastrointestinal outbreaks by food poisoning). They often cause large outbreaks in closed communities in a variety of environments such as hospitals, nursing homes, schools, kindergarten, restaurants, cruise etc where, once the virus has been introduced, the infection spreads very quickly.
Although Noroviruses can be detected throughout the year, it has been clearly observed that there is a seasonal prevalence with peaks during autumn and winter.
Noroviruses are grouped into five Genogroups (GI to GV), of which GI and GII are involved in most acute cases of viral gastroenteritis in humans, being the main cause of epidemic gastroenteritis (Vomiting, watery diarrhea and abdominal cramps). Symptoms such as malaise, nausea, fever or fatigue.
The incubation period of the disease occurs between 12 and 48 hours, whereas the infection can last between 12 and 60 hours. People such as children, patients of an advanced or chronic age, are the main affected.