Diarrhea in the news

September 23, 2018

Even if you are not interested in the spread of intestinal infection, you probably haven’t missed all the discussion of major outbreaks in the US over the past several weeks.  We aren’t talking about the developing world here—diarrheal illnesses have been a scourge in those areas for centuries—the problem is becoming more and more common in our country.

The culprits in these outbreaks vary, but include all the usual suspects:  Giardia (unusual, actually), norovirus, and E. coli, for example.  For all, the mechanism of spread is the same:  traces of the feces of an infected human spread the bug through a community.  Sometimes, the food itself is directly contaminated during processing.  The recent recognition of the parasite Cyclospora in US cilantro is an example of this (https://www.foodsafetynews.com/2018/09/fda-commissioner-says-science-will-answer-cyclospora-questions/).  Other times, surfaces are contaminated by someone who failed to practice proper hygiene after using a toilet and unwitting passersby pick up traces and contaminate themselves.  About 300 people were recently sickened by norovirus at a McDonalds in Brevard, North Carolina by this mechanism (https://www.foodsafetynews.com/2018/08/restaurant-food-safety-is-an-oxymoron/). Salmonella was implicated in a similar outbreak at a Mexican restaurant in Fort Collins, CO (https://www.foodsafetynews.com/2018/09/colorado-restaurant-goes-out-of-business-following-salmonella-outbreak/).

The one thing about which you haven’t been reading much is intestinal infection spread by contaminated water.  Although this mechanism certainly does occur, it is actually a very inefficient mechanism of spreading infection and is rarely reported in the US.  When it is reported, it is generally consequent to engineering or maintenance problems in public water or sanitation systems.  Although the outdoor community frets unceasingly about the dangers of wilderness waters, a point I have been making for decades continues to be true:  documented spread of intestinal infection from North American wilderness waters is virtually unheard of.  When it comes to the problem of intestinal infection in the United States, direct personal spread is the only important mechanism of transmission.

Although this concept has slowly been making its way into outdoor education curricula of late, we still have a long ways to go.  Too many outdoor educators continue to whine incessantly about the need for treatment of backcountry water, while giving nary a nod to the importance of personal hygiene.  Yet, evidence of the importance of this continues to grow.  Consider, for example, a recent publication demonstrating direct transmission of norovirus among Colorado River rafters (https://www.ncbi.nlm.nih.gov/pubmed/25890859).  In days past, folks might have blamed the river itself rather than the dirty hands of the rafters!

The Adirondacks, sadly, have continued to be an epicenter of water-related nonsense.  Recently, the magazine of the Adirondack Forty-Sixers, Adirondack Peeks, published an absurd piece on water quality by an “expert” who clearly understood nothing about water borne illness. In nearly three pages of commentary on the risks of intestinal infection in the Adirondacks, there was not a single mention of group hygiene and handwashing.  Inexplicably, the piece was accompanied by commentary from a physician (a gastroenterologist, no less) without a single mention of personal hygiene.  Yet, I am sure that this physician, in her professional life, recognizes the prime importance of handwashing.

I have pretty much given up on urging folks to ditch their water purification systems for most treks.  This has seemed to become far too ingrained to change.  At the very least, however, can we just encourage people to add soap or gel sanitizer to their equipment lists?