Just Say No to Norovirus

Norovirus is a lovely little pathogen that makes the rounds every year.  It is extremely contagious, so much so that it frequently closes schools.  Formerly known as the Norwalk virus as it was named when identified in the early 1970s, it causes about 20% of acute gastroenteritis ("stomach flu") cases.  Norovirus is the leading cause of food-borne illness in the world and ranks fourth in deaths due to food poisoning.  This includes over 50,000 deaths of children each year, mostly in developing countries.  Like the common cold, norovirus comes in several genotypes that evolve over time so they can make you sick again.  Because nausea and vomiting weren't fun enough the first time.
This virus will sicken about 20 million people in the US this year, and 600-800 will die, primarily young children and the elderly. Fortunately, there is a lot we can do to protect ourselves.

The virus is passed in stool and vomit.  So if you get it, it's possible that you got someone else's bodily grossness into you somewhere along the way, probably by eating or drinking it.  Primary person-to-person transmission of the virus happens that way.  Probably because they didn't wash their hands after using the toilet.  Perhaps because you didn't wash yours after touching whatever they touched and before touching your face or mouth.  Or because you didn't wash yours well enough.

Secondary person-to-person transmission occurs by sharing food, drinks, or utensils.  If those were the only ways norovirus spread, thorough handwashing and not sharing food or drink would protect us.  However, water can also be contaminated with norovirus, and thus contaminate everything it contacts--ice, eggs, fruits, and salads.  Infected food handlers can pass it on to cooked foods.  And, unfortunately, norovirus also survives pretty well on doorknobs, stairway railings, and other surfaces for days to weeks.  That's why schools get closed down and disinfected during outbreaks.  There are also some recent studies indicating that norovirus may aerosolize during vomiting so that it can be passed by droplets in the air.  If that makes you feel any better.

Norovirus in the northern hemisphere is most common from November to April, with the peak season being December through February. Symptoms of a norovirus infection include nausea, vomiting, and abdominal cramps.  Diarrhea is less frequent.  There may be a low-grade fever.  Unlike a lot of other illnesses, the moment you contract norovirus, long before exhibiting symptoms, you are contagious to others. While the symptoms usually pass in one to two days, the patient is still contagious for at least three days and perhaps up to two weeks afterward.  But in American society, if you're feeling better, you had better be at work and school.  And spread the joy of this highly infectious virus further. 

Careful handwashing is the best way to prevent contracting a norovirus infection.  Hand sanitizers are of little efficacy because norovirus is a non-enveloped virus.  It's a tough little bugger.  You really need soap and water and vigorous, meticulous scrubbing for your hands and bleach and hot water for surfaces.

And now, because this is a food-borne illness, let's bring it back to food safety.  Once a person has caught norovirus, before the symptoms appear, that person is shedding norovirus and infecting people and contaminating food.  It's not a problem if the food is thoroughly cooked, like in canning.  But what if Grandma was exposed to norovirus on Monday morning, and then prepared some food for the freezer, to be eaten later?  Grandma gets sick Tuesday evening.  Everything Grandma touched, all that food, is contaminated.  Even if it's not eaten for months, because freezing temperatures don't affect norovirus.  It has to be cooked to be killed.

There are no vaccines for norovirus.  As far as natural remedies go, pomegranate juice may hasten recovery.   Blackberry root decoction is another good choice.

Links to related posts:
Food Poisoning Overview
Medicinal Uses of Blackberry
Hand Sanitizers
Proper Hand Washing Protocol 

For further reading:
https://www.medicinenet.com/norovirus_infection/article.htm
https://eportal.mountsinai.ca/Microbiology/faq/norwalkfaq.shtml#six
https://www.cdc.gov/norovirus/trends-outbreaks/burden-US.html
https://www.health.ny.gov/diseases/communicable/norwalk/fact_sheet.htm
https://www.who.int/foodsafety/areas_work/foodborne-diseases/infographics_global_en.pdf
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3168661/