Re: Norwalk Virus in the Valley

A friend just returned yesterday from a week camping in Upper Pines. He said one of his kids came down with the Norwalk virus while there and passed it around the family during the week. Has anyone else heard about this?

- Dave

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dagr47
A friend just returned yesterday from a week camping in Upper Pines. He said one of his kids came down with the Norwalk virus while there and passed it around the family during the week. Has anyone else heard about this?

Somebody drank straight out of the Merced?

How was this diagnosed?

Years ago, I heard a few people made snide reference to the "Curry Hurries" (Yosemite Park & Curry Co.), but I never had any problem with the employee meals. Chlorine bleach will kill the norovirus, and I've known campers that made absolute certain they they included Chlorox to add to their dishwashing effort.

I sure hope it doesn't upset a bunch of vacations, though.

Here's an info site:

http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-qa.htm

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Old Dude

As far as "campers that made absolute certain they they included Chlorox to add to their dishwashing effort",
I've been camping there for years in just about every Valley campground, and never used bleach in my dishwater,
and have never gotten ill. The tap water is very pure there.
I would point out this is the summer, it's very hot there right now, and children love to splash around and play in
the Merced. If he or she swallowed a little river water, that might possibly explain how they contracted it...

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PineCone
The tap water is very pure there.

That's because it is chlorinated.

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I would point out this is the summer, it's very hot there right now, and children love to splash around and play in
the Merced. If he or she swallowed a little river water, that might possibly explain how they contracted it...

That would be my first guess.

Chlorinated huh? Sure doesn't taste like it! Maybe it's the great ambiance of the place that makes it taste so good to me!

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PineCone
Chlorinated huh? Sure doesn't taste like it!

It tastes like it to me.

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Maybe it's the great ambiance of the place that makes it taste so good to me!

The chlorination isn't real heavy. That might help.

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dagr47
A friend just returned yesterday from a week camping in Upper Pines. He said one of his kids came down with the Norwalk virus while there and passed it around the family during the week. Has anyone else heard about this?

- Dave

When did the first symptoms occur in relation to arriving in the valley. Most likely acquired outside the park or from a fecal-oral route (poor hygene in toilet facilities).

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The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan

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Frank Furter

When did the first symptoms occur in relation to arriving in the valley. Most likely acquired outside the park or from a fecal-oral route (poor hygene in toilet facilities).

This is a pretty common scenario...go camping, get sick, blame the water. Much easier than finding the real cause.

Most likely it's a case of poor sanitation, possibly contaminating something they ate, and has nothing to do with drinking water or washing dishes. Having the whole family get it only reinforces the likelihood of it being a food contaminant.

I've been drinking from the Merced for some time, never had any issues with it, nor have other family members. Wouldn't even think of carrying chlorine with me to wash dishes. In fact, personally I'd be more suspicious that repeated ingestion of chlorine (a poison, btw) is a more likely source of problems over the long haul, than 'smart' drinking of river water.

A little swallowed water while playing in the Merced? I surf in the ocean water near Morro Bay several times a week, and in that environment it's nearly impossible to avoid occasional swallowing of a bit of ocean water. The abundance of seagulls, pelicans, cormorants and others in the area assure that the water is not by any means "clean", yet I've never had any issue with that either. While there are some cautionary times right after a rain, where water from land, complete with dog and cattle fecal matter would be washed in via the drains, under normal circumstances the bird contamination is apparently not severe enough to cause problems.

So why would the Merced, which doesn't go through cattle country or have farms washing their effluent down into it, be so severely polluted? The answer is, it's not.

As a kid, I drank from Colorado rivers as a normal thing. Later we were swept into "California paranoia" of if you even touched river water, you practically needed a bath in Lysol. Happily, that's nothing more than paranoia, and if you drink using due care, the likelihood of a problem is extremely remote...maybe no more than the likelihood that the guy in the food concession touched the inside of your cup with his contaminated finger, and maybe less.

It's also possible that the extreme sanitary practices we've become accustomed to actually contribute to our vulnerability. Use of antibacterial soaps and cleaning products could affect our body's ability to naturally deal with minor things that normally wouldn't bother us. The camping environment, with many of these practices inconvenient or unavailable, is very likely to provide contaminated food or just hand/mouth transfer of contamination. Then they remember the propaganda and blame the water, when it has nothing to do with it.

Obviously though, you have to use water with common sense. A farm or livestock upstream, stagnant water, or anything suspicious looking would be something to avoid, but the Merced water, at least upstream of the Curry bridge, looks and tastes great.

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Gary
Yosemite Photo Galleries: http://www.pbase.com/roberthouse/yo

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Sierrafan
I've been drinking from the Merced for some time, never had any issues with it

I've heard claims like that quite often over the years. But many water born illnesses take a week or two to show symptoms and by that time you would never equate them with the water you drank. Many giardia infections are asymptomatic. While it may not have been the water that caused the OP's family to get sick (we don't even know if it was really norovirus or how this was diagnosed) it still is a very bad idea to be drinking water from the Merced without treating or filtering it first.

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eeek
I've heard claims like that quite often over the years. But many water born illnesses take a week or two to show symptoms and by that time you would never equate them with the water you drank. Many giardia infections are asymptomatic. While it may not have been the water that caused the OP's family to get sick (we don't even know if it was really norovirus or how this was diagnosed) it still is a very bad idea to be drinking water from the Merced without treating or filtering it first.

That could (and had been) debated for endless loops. Since I know you have looked in at the Whitney board, I assume you've read Bob Rockwell's articles on it, which say things similar to this
http://www.adventureplus.org/latimes.htm

All that aside, it's a nice feeling to drink water the way we were built to do; we weren't built to drink chlorine, and don't have a filter built in to our teeth. I found it depressing for years to look at all those streams and rivers and think of them as practically poison...what a nice feeling to dip my cup in and take a drink of the icy cold water from the Merced, or other river, using the same common sense I was taught as a kid. I don't think it's a bad idea at all, but of course everyone needs to determine what suits them.

Since most of the gastric problems from backpacking or camping have an unproven cause, there is little proof either way; if someone says I got giardia from the water the day after we got to the campsite, people will just assume it to be true. And, even if they DID get true giardia, then the question becomes where did they get it. From a scientific or logical viewpoint, you just can't assume those things if you want the truth, you have to do the legwork. Which isn't easy, so it's easy to blame something and ignore whether it's fact or assumption.

I can say I never got sick from the Merced water, and maybe next time I will. And you can say you got sick every time you went to yosemite, and if you didn't drink the Merced water, blame it on washing a dish without using chlorine, but that has no more basis in fact than blaming the full moon. So you may only feel comfortable assuming everything needs to be sanitized, while I, being skeptical of doctors, pharmaceutical companies, scientists with preconceived notions, people with $$ to gain by water purification, and people who "heard" it's dangerous, may feel differently. We were built to drink water, so I would choose to assume that as long as it's in its natural state (which the Merced above the valley is), my body should be able to handle it fine, despite the presence of animals or birds in their natural environment, and even to some extent beyond that (look at what dogs drink).

And so far we're both right. You filter and sanitize and don't get sick. I drink from sources that common sense tells me are OK, and don't get sick. If you get sick tomorrow and I don't, that doesn't mean it's wrong to filter or sanitize, and vice versa.

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Gary
Yosemite Photo Galleries: http://www.pbase.com/roberthouse/yo

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Sierrafan

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eeek
I've heard claims like that quite often over the years. But many water born illnesses take a week or two to show symptoms and by that time you would never equate them with the water you drank. Many giardia infections are asymptomatic. While it may not have been the water that caused the OP's family to get sick (we don't even know if it was really norovirus or how this was diagnosed) it still is a very bad idea to be drinking water from the Merced without treating or filtering it first.

That could (and had been) debated for endless loops. Since I know you have looked in at the Whitney board, I assume you've read Bob Rockwell's articles on it, which say things similar to this
http://www.adventureplus.org/latimes.htm

All that aside, it's a nice feeling to drink water the way we were built to do; we weren't built to drink chlorine, and don't have a filter built in to our teeth. I found it depressing for years to look at all those streams and rivers and think of them as practically poison...what a nice feeling to dip my cup in and take a drink of the icy cold water from the Merced, or other river, using the same common sense I was taught as a kid. I don't think it's a bad idea at all, but of course everyone needs to determine what suits them.

Since most of the gastric problems from backpacking or camping have an unproven cause, there is little proof either way; if someone says I got giardia from the water the day after we got to the campsite, people will just assume it to be true. And, even if they DID get true giardia, then the question becomes where did they get it. From a scientific or logical viewpoint, you just can't assume those things if you want the truth, you have to do the legwork. Which isn't easy, so it's easy to blame something and ignore whether it's fact or assumption.

I can say I never got sick from the Merced water, and maybe next time I will. And you can say you got sick every time you went to yosemite, and if you didn't drink the Merced water, blame it on washing a dish without using chlorine, but that has no more basis in fact than blaming the full moon. So you may only feel comfortable assuming everything needs to be sanitized, while I, being skeptical of doctors, pharmaceutical companies, scientists with preconceived notions, people with $$ to gain by water purification, and people who "heard" it's dangerous, may feel differently. We were built to drink water, so I would choose to assume that as long as it's in its natural state (which the Merced above the valley is), my body should be able to handle it fine, despite the presence of animals or birds in their natural environment, and even to some extent beyond that (look at what dogs drink).

And so far we're both right. You filter and sanitize and don't get sick. I drink from sources that common sense tells me are OK, and don't get sick. If you get sick tomorrow and I don't, that doesn't mean it's wrong to filter or sanitize, and vice versa.

I would not suggest that both points of view are right. Because there is uncertainty in data and medical conclusions are not absolute, there is a tendancy to view health issues with a certain abandon and nihilism that suggests that all options are reasonable. Tuberculosis, polio and typhoid fever are all natural events. That does not justify arguments against making reasoned efforts to mitigate them. Many people, including myself have drunk water without filtering or chemically treating it. That does not mean that it was entirely safe to drink or entirely free of disease-- merely that the odds were in our favor and we won. My brother, following a family tradition of drinking from streams directly, acquired giardiasis that involved the loss of 20 pounds and many medical interventions before it was treated fully.
The Merced above the valley is not in a "natural state" given the presence of infected rodents, horses, and humans and the myriad diseases that can be encountered including crypto, hepatitis, e. coli, giardia, etc. Odds are that you will do fairly well drinking from fast moving clear water close to ice fields. However it is a risk much greater than any known effect of properly iodine or chlorine treated or filtered water. Best policy is to treat all surface water, even from the mountains. Even if there is a miniscule risk from treating water, it is worth that tiny risk to avoid more serious problems. One could argue that seatbelts are inherently dangerous because they can cause internal injuries during severe accidents-- nevertheless the overall benefit of seatbelts is clear.

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The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan



Edited 1 time(s). Last edit at 07/04/2009 09:42AM by Frank Furter.

Norwalk agent or norwalk virus is one of the most infectious viruses known. Infectious dose in 50% of people may be as little as 1 virion. Many diseases require hundreds, thousands or even millions of infectious particles to produce an infection.

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The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan