Giardia
One of the issues that’s been bubbling around in my mind about Tramping New Zealand is my thoughts about water filtering in the New Zealand backcountry.
Years ago, I wrote a perhaps controversial webpage that suggested it was pointless to filter water from mountain streams. I felt the real hotspots were at huts. But I just made assertions and never spent the time to substantiate them.
AI has helped me find the evidence that my hunch is, in fact, right.
It comes down to overseas experience being applied to the very different New Zealand conditions. Europe has herds of cows grazing on alpine pasture, and North America has beavers building dams and contaminating slow-moving water, as well as bears doing what they do adjacent to streams when they go fishing. These large mammals each produce billions of pathogens a day that get into water catchments. Overseas, this is a real issue.
New Zealand has few large animals and steep, fast-flowing streams with lots of turbulence to disperse the rare microbes that find their way to the water.
The real dangers for contamination come from another source.
People.
Due to the generally damp conditions and the large number of recreational huts in the backcountry, tramping in New Zealand means you don’t necessarily have to carry a tent. So, people congregate at huts, use the only longdrop, and touch the tap at a solitary water tank.
Infection spreads by moving pathogens from the inside toilet latch to the water tank tap to the hut door handle, to the kitchen bench, and generally spreading around. An alternative pathway is by walking through infected animal droppings, and then touching your boots, whence it goes everywhere. Most people don’t know that while alcohol-based hand sanitiser is effective on E. coli and a few fragile pathogens, it is not effective at all on Giardia, norovirus, or Cryptosporidium.
What works?
Soap. A 20-second minimum scrub of your hands. Washing the pathogens off under running water is what is required.
Basic hand hygiene, rather than filtering some of the purest water in the world and thinking that will protect you.