Norovirus is a nasty little virus that causes tons of misery every winter. It is an RNA virus that infects the gastrointestinal tract causing violent vomiting and diarrhea. About 12 to 48 hours after being infected, rapid symptom onset will lay you flat for about a day. Even better, immunity to this virus fades in a few months and you are susceptible to a new attack. A particularly nasty strain of norovirus has been circulating in my area and my family came down with it just this weekend. The virus is highly contagious, with only 10 virus particles ingested in the mouth being able to cause disease. Much to my surprise, neither my son nor I became ill. This got me wondering why? Follow the link to learn the answer to this story.

A quick search on pubmed for norovirus human resistance brought up a slate of articles. A review by Jose Flores and Pablo C. Okhuysen indicated that about 20% of the white population has a mutation in the FUT2 enzyme that is involved in creating carbohydrate structures on the surface of our cells. They thus cannot form the normal receptor that many strains of norovirus attach to for cellular invasion. These individuals are resistant to attack by norovirus. However, it is possible for them to contract illness if inoculated with large amounts of virus, presumably by an alternative pathway, or by certain strains that use a different receptor. Could my son and I be resistant to this strain? It is possible. It is also possible that we just got lucky this time.

The article goes on to discuss other enteric pathogens, many of whom use similar receptors, suggesting that individuals with mutant FUT2 enzymes, may also be resistant to other forms of gastroenteritis.