By Dr. Gus Benner
In 1968, an elementary school in the small Ohio town of Norwalk experienced an outbreak of diarrhea. This was severe enough that it came to the attention of public-health authorities, and resulted in the discovery of the virus causing the disease, named the Norwalk virus. (Remember the origin of Lyme Disease, in Old Lyme, Connecticut? Maybe your town, too, could become famous if enough people got sick.)
Fast-forward to November 2006. A cruise ship in the Caribbean also experienced an outbreak of diarrhea, with some 400 people being affected. They had to disinfect the entire ship. It made the headlines and was due to the same virus, recently renamed the Norovirus, more accurately a group of viruses in the same genus.
Have we learned much in 40 years?
Could this hit your multi-day backpack or paddling trip?
The disease here is gastroenteritis, specifically viral gastroenteritis. The most common agent is Norovirus, but there are a few others, e.g. Rotavirus and adenovirus. Incubation is usually 1-2 days. Usual symptoms are nausea, vomiting, and diarrhea, with some abdominal cramping. Although it can be quite severe, it is usually short term, 3-5 days. There is no specific treatment, recovery is predictable, and the major management is fluid replacement. (These symptoms can mean something else, too. Check this note.)
Gastroenteritis agents are transmitted by food, undercooked fish and shellfish, and the yucky-sounding fecal-oral route. A food source is really due to a person -- usually a food handler -- and often a major outbreak can be traced to a single person. Clearly a food handler with diarrhea should not return to work until free of symptoms 24-48 hours.
The fecal-oral route simply refers to the universal but hard-to-acknowledge fact that we touch ourselves, and we touch others, and we touch common objects (doorknobs) that others touch. The culprit here is our hands.
Hand-washing is certainly the backbone of personal hygiene. As I briefly review the literature, most studies are concerned with bacteria, but anti-virus activity has also been addressed. Plain soap is good, and much better than plain water or no washing at all. In a wilderness setting, we just need to use biodegradable soaps and be well away from waterways.
Alcohol-based cleansers (ethanol or isopropanol) are more effective against both bacteria and viruses, and are the current recommendation. A small bottle of an alcohol-based gel that is used without water is a reasonable addition to the commissary equipment, for each person on the crew to use a squirt before preparing food. I found at an outdoor door supply store a hand sanitizer that seemed quite convenient, containing Benzyl Ammonium Chloride. This is good for some bacteria but not all, and probably less effective overall than alcohol.
Another concern is disinfecting dishes and tableware used by more than one person. The most effective agent here is chlorine, as in sodium hypochlorite (plain bleach) or perhaps stronger chlorine preparations used as pool shock in hot tubs. A formula for bleach is to use ¼ cup bleach in one gallon (1 tablespoon in a quart) as a final rinse or soak. It should remain in contact with the item for at least 10 minutes, or simply let the item air dry without wiping or water rinse. Chlorine evaporates, so taste is not a problem.
Have we learned much in 40 years?
Just listen to what our mothers said: "Wash your hands!"
NOTE: The primary symptoms of gastroenteritis are vomiting and diarrhea -- basically emptying the gastrointestinal tract -- and there may be associated cramping abdominal pain. This contrasts with the patient who has primarily abdominal pain, with some nausea and maybe a loose stool. This presents a whole different set of diagnostic possibilities, some of which require evacuation and surgery. And although I am focusing here on viral gastroenteritis, mainly because it is common and dramatic, there are obviously many other bacterial and toxic causes of gastrointestinal upset. The details get too complex to deal with here, however.