Why Rockwell is Wrong about Giardia

[Colter]

I really want to request this thread get locked unless someone comes up with a reason not to..
Russ

Why do you feel it's so important to shut down a thread that is relative to the high Sierra, a thread in which others want to participate, and a thread that is purely optional to read? You were trying to stop it from the beginning.

[rlown]

well.. we have at least 4 threads on water treatment. and they haven't been tickled for a while. Is that a good start?

we read the thread.. but does it mesh into the overall site knowledge.. no. unless it's merged by admin or otherwise.

[RoguePhotonic]

I have to seriously doubt that several backpackers come in a week in Mammoth with Giardia. It takes allot longer than most people spend on a single trip to take effect. Also that level of infection would prompt serious investigation into the problem.

[Colter]

I have to seriously doubt that several backpackers come in a week in Mammoth with Giardia. It takes allot longer than most people spend on a single trip to take effect. Also that level of infection would prompt serious investigation into the problem.

Why would a Dr. publicly go on record and say it if it wasn't true? Not only that, but I was one of those patients and I know of several other people who were, also. It's one of the most "popular" places for PCT hikers to get treated for giardia, and they, as often as not, get sick in the middle of nowhere.

Also, those cases wouldn't be investigated unless it was an outbreak: A disease outbreak is the occurrence of cases of disease in excess of what would normally be expected in a defined community, geographical area or season. Giardia is common, it happens every year, so a few backpackers a week wouldn't be an outbreak. Plus, giardia usually isn't reported at all. In that quoted physician's county (Modoc) no cases were OFFICIALLY reported in 2008-2010. Including my case.

[rlown]

ok.. everyone.. just let colter answer the question.. what do you want from this thread?

[sparky]

Just because people get giardia doesn't mean they got it from their drinking water.

If 1/3 of samples from sierra water have giardia than I am obviously immune. Yay!

This is getting silly

[Colter]

ok.. everyone.. just let colter answer the question.. what do you want from this thread?

In 2010 I switched from treating water to not treating water, specifically because of the Rockwell paper. I got giardia within a few weeks in the High Sierra. I was so sick it took me much of a day to make it four miles back to a road. When I got back I looked at the Rockwell paper and found out that the science was riddled with huge flaws. I also found out there were lots of other hikers reporting getting giardia in the Sierras.

I've likely read every thread on the topic in this forum and most of the threads from the past few years on most of the other backpacking forums as well. I started chasing down peer reviewed papers and looking at all manner of studies and surveys. I ordered a book on giardia and was just talking to water treatment experts in California today.

Despite what you might think I have learned a lot and there are other people who are interested in something beyond the usual exchange of anecdotes and opinion. It's an interest of mine and I think it can help other people make more rational risk assessments. This forum seemed like one of the very best places to discuss it. Perhaps I was wrong.

Sparky, you are absolutely correct that not everyone who gets giardia during/after backpacking got it from drinking water, but many of them have, no doubt about it. You might well be more or less immune, or just lucky to this point. Even in verified waterborne giardia epidemics large numbers of people are asymptomatic.

As I've said before, it's rational to not treat, or treat, if you've looked at the best information and made a reasonable risk assessment. I'm not trying to force my risk assessment onto anyone else.

[ERIC]

I'll allow this to go on for a little longer. Keep the topic civil, and it stays open as long as new information is presented. Same arguments over and over again gets locked on grounds of being unproductive.

I encourage you all to be polite in your arguments, yet thick-skinned enough to recognize respectful jabs. Don't take things too seriously.

[RoguePhotonic]

Any speculation on why a doctor would lie if they did would just be counter productive.

Now we might be able to narrow it down when you say the PCT hikers come through and have it. Is it only the PCT hikers or is there a large amount of other general backpackers? You might be able to narrow it down where they are getting it. Probably some where in the Southern Sierra where there are allot of cows.

[dave54]

Some time ago I read several papers on giardia in mountain areas (do not recall the specific papers), but I remember one significant (to me) thing when I reviewed the methodology of the studies.

The papers that claimed low concentrations in the water samples were taken in the early summer, where the samples that showed higher concentrations were taken in the late summer to fall. This is entirely logical to me. Early summer would have higher flows of colder and cleaner water from fresh snowmelt. Later in the summer/fall water flows would be warmer, slower, and exposed to the elements/contamination for several months. None of the papers addressed the seasonality of the sampling and how that could effect the results.

If anyone in the research field is reading this a new opportunity for a study is presented: take samples from the same point in a stream over the course of a year and compare the sample results.

I also recall a study on water quality in Oregon, and E.coli. Where cattle had grazed the E. coli was higher, as expected. But additional research showed the E.coli was predominantly a human strain, not bovine.