By: Paul

Paul — Wed, 11 Aug 2010 02:34:00 +0000

What about cool dry weather assists norovirus outbreaks? If I had to throw out a grabbag of possibilities to investigate, I’d nominate 1) cold weather keeps people indoors where fomite contact and recirculated air (aerosol contact with vomitus or toilet flush aerosol) contact are increased, but then what does “dry” have to do with anything; 2) maybe humidity helps break down the protein coat so that they last longer in dry environments; 3) maybe cool and dry is a proxy factor for behavior that tends to spread the virus such as staying indoors or less handwashing. Cool dry hands feel clean, with warm hands in humid weather your hands feel oilier. I would not however think that the weather had anything to do with immunity suppression. From what I’ve heard, the ancient superstition that drafts or chill air cause disease in virtue of their temperature is just that, and that many studies have shown that any winter increase in the common cold is not from suppressed immunity but more people in closer contact indoors in the winter; subjecting people to drafts, cold water, etc. does not increase the number of colds, influenza etc. (“influenza” I hear derives from “influence”, meaning “inflow”, i.e., the old idea that disease comes in on a draft). Anyway is there any good research on why norovirus is a “winter” vomiting disease and specifically why “cool, dry” conditions correlate with outbreaks, as opposed to simply “cool”?

Comments on: Predicting norovirus epidemics

By: Paul