Contributed by Poyin Chen

California is currently experiencing an outbreak of Norovirus. This nasty little virus, also known as the winter vomiting disease, infects via contact with infected surfaces or people and wreaks havoc on the digestive system. Norovirus infections result in gastroenteritis as well as fever and body aches, but the infection is self limiting and usually clears up on its own in a few days.

Despite being resolved in a matter of days, Norovirus infections, as well as all other GI infections, leave a lasting impact on the microscopic communities within the gut. During the initial stages of the infection when the GI flood gates are open, everything is forcefully expelled from the GI tract. This mass exodus includes the established gut microbiome, resulting in a severe decrease in the total numbers of microbes in the GI tract. Reestablishment of the gut microbiome community diversity is a process that will take months and will not return to the preexisting community structure before infection.

While we can go back to the same dietary habits (and life as we know it) within a week of contracting a Norovirus infection, the dramatic and lasting changes to our gut microbiomes means that the metabolic profile of our gut will take time to rebuild [1]. Losing whole genera of bacteria means losing all of the metabolic capabilities these genera provided [2]. Many of these bacteria are able to break down molecules that we otherwise would not be able to digest on our own. Oligosaccharides that cannot be broken down by our digestive enzymes will remain intact throughout its passage through our gut.

Thankfully, the ubiquitous nature of bacteria means that ingesting bacteria on a daily, if not hourly basis is unavoidable. I, myself, like to help diversify my gut microbiome by giving my dog extra kisses and licking chocolate off of my fingers. Hey, it couldn’t hurt, right?*

*Disclaimer: It probably could hurt. That may have been how I got sick in the first place but I love my dog and my chocolate too much to stop.


  1. David LA, Materna AC, Friedman J, Campos-Baptista MI, Blackburn MC, Perrotta A, Erdman SE, Alm EJ: Host lifestyle affects human microbiota on daily timescales. Genome Biol 2014, 15:R89.
  2. Tremaroli V, Backhed F: Functional interactions between the gut microbiota and host metabolism. Nature 2012, 489:242-249.


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