A norovirus is a virus that can cause acute viral gastroenteritis (commonly known as the "stomach flu"). These viruses are highly contagious and can survive extreme hot and cold temperatures -- they can even survive in water treated by chlorine. Because they are so contagious, it's important to practice good hygiene habits when recovering from an infection.
Noroviruses are a group of related RNA (ribonucleic acid) viruses that cause acute viral gastroenteritis (also known as the "stomach flu"). Norovirus was recently approved as the official genus name for the group of viruses provisionally described as "Norwalk-like viruses" (NLV). They are part of the genus Norovirus and the family Caliciviridae.
Noroviruses are named after the original strain, "Norwalk virus," which caused an outbreak of gastroenteritis in a school in Norwalk, Ohio, in 1968. Currently, there are at least four norovirus genogroups (GI, GII, GIII, and GIV), which, in turn, are divided into at least 20 genetic clusters.
Several other names have been used for these viruses in the past, including:
- Norwalk-like viruses (NLVs)
- Caliciviruses (because they belong to the virus family Caliciviridae)
- Small round structured viruses, or SRSVs (because of their appearance).
Noroviruses are relatively resistant to environmental challenge: They can survive freezing, temperatures as high as 140°F (60°C), and have even been associated with illness after being steamed in shellfish. Moreover, these viruses can survive in up to 10 ppm chlorine, well in excess of levels routinely present in public water systems.