# 4370
If you’ve ever been stricken by Norovirus then you know that for the first 12 hours you are afraid you may die, and for the second 12 hours you are terrified that you won’t.
Known in the UK as the Winter Vomiting virus, Norwalk-like (genus Norovirus, family Caliciviridae) viruses are part of a family of single strand RNA viruses that cause acute gastroenteritis in humans.
They are infamous for spreading rapidly through cruise ships, hotels, hospitals, schools and long-term care facilities. While the symptoms may be dramatic and miserable (vomiting, diarrhea, stomach pains, etc), it generally runs its course in 24-48 hours, rarely resulting in death.
Immunity to the virus is generally short-lived and incomplete, and reinfection several times over a person’s lifetime is common. Some people appear more prone to infection than others, with the virus having a greater affinity for blood type O.
For reasons that are less than clear, Norovirus outbreaks exhibit high seasonality, occurring most often in the winter months.
Which brings us to an interesting article today from the CanWest News service that may shed some light on this mystery. No firm conclusions, mind you. But an interesting theory . . .
Virus may incubate in icy lakes: researchers; Norwalk affects millions annually
Monday, February 22nd, 2010 | 12:41 am
Canwest News Service
Norwalk virus, a gut-wrenching fixture of Canadian winters whose source and seasonal nature have long been a mystery, may originate in drinking water drawn from lakes whose cool winter temperatures keep the microbe nicely preserved, suggests a new study.
University of Toronto researchers, comparing Norwalk outbreaks to river water flow and lake temperatures, theorize that a near-endless "feedback loop" sends the virus from human waste to surface waters, then to water treatment plants that are unable to eliminate the bug, and finally back into household faucets.
The theory, if proven, raises the question of whether tap water should be treated with ultraviolet exposure, virtually the only way to kill the hardy viruses, the researchers say.
