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View Full Version : Viruses - legitimate worry or non-issue



Big Hill
09-02-2016, 14:25
Newb warning....:D

I recently purchased a Sawyer squeeze after reading a ton of reviews. This weekend is the first hike long enough where I will have a legitimate need for it. I'll be using it on the AT near the rollercoaster (NoVa).

Should I be concerned that it doesn't filter out viruses and consider using chemical as well ot is the Sawyer enough. I really don't know as much about this as I should...other then I know I am not interested in drinking from the source....

bigcranky
09-02-2016, 14:29
Viruses are generally not an issue in the US. Lots of hikers use the Sawyer Squeeze (including us) and it works fine.

If I were traveling out of the country I might take chemical treatment depending on where I was going, but not here.

DuneElliot
09-02-2016, 14:39
Not a concern...very rarely will a virus be an issue, and then only when someone with Noro virus (the only waterborne virus occasionally found in the US) has pooped improperly upstream. The chances are slim to none that you will encounter it...look at the statistics; I've never heard of it affecting AT hikers. There was one place in AZ/CA/UT that recommended chem treatment of the water but only because they had confirmation of an incident of Norovirus in the water.

HooKooDooKu
09-02-2016, 14:41
Yea, viruses are generally not an issue in the U.S. back country.
But it's still a good idea to obtain your water from a flowing sources when possible rather than from stagnant pools.

Bubbabuzz
09-02-2016, 14:56
I have no hesitation using my Sawyer filter in running streams on and around the A.T. I've used the mini and full sized Sawyer.

dudeijuststarted
09-02-2016, 15:13
Plenty of flowing water in the RollerCoaster. Have fun in there you lucky son-of-a-gun.

P.S. Keep an eye out for hidden campsites. There's an awesome "island" tucked away by a very heavy flowing stream / waterfall.

Offshore
09-02-2016, 15:16
The old adage that viruses are not an issue in the US really needs to be rethought. If you are hiking a busy trail such as the AT with other humans that may not follow best practices for "waste management", your potential exposure to viruses may not be as unlikely as the conventional wisdom would have you believe.

dudeijuststarted
09-02-2016, 15:38
The old adage that viruses are not an issue in the US really needs to be rethought. If you are hiking a busy trail such as the AT with other humans that may not follow best practices for "waste management", your potential exposure to viruses may not be as unlikely as the conventional wisdom would have you believe.

I can recall at least one really bad situation in the 100 mile. OP should be good in VA though, as long as they adhere to other posters "no stagnant pools" advice. Good point though, always gotta wonder what's comin'.

Another Kevin
09-04-2016, 19:59
The old adage that viruses are not an issue in the US really needs to be rethought. If you are hiking a busy trail such as the AT with other humans that may not follow best practices for "waste management", your potential exposure to viruses may not be as unlikely as the conventional wisdom would have you believe.

That assessment is based not so much on "might you contract a viral infection" as "might you contract a life-threatening viral infection." The US has very little poliovirus, coronavirus, or hepatitis A in the population, so it's vanishingly unlikely that you'd encounter them in the field. BK virus and JC virus (the commonest polyomaviruses) are generally not dangerous, or indeed even noticeable, to immunocompetent people (if you're HIV positive, a transplant recipient, or a chemotherapy patient, the balance shifts). That means that the worst you're likely to get from contaminated water would be norovirus, coxsackievirus, or rotavirus. While those can all have you wretchedly ill for a few days, they're unlikely to be dangerous to an otherwise healthy adult.

You're much more likely to get any of the above infections from contaminated hands than from contaminated water, so wash your @#$%! hands and don't let other hikers handle your food (or eat food they've touched). That's far more important than anything you can do in the way of water treatment. Don't believe anyone who tells you that the occasional dab of hand sanitizer is enough. Bring soap. (I also don't begrudge the extra weight of a bucket and a piece of Sham-Wow that serves me for a towel.)

Lauriep
09-05-2016, 09:43
Norovirus can be a concern on the Appalachian Trail or in crowded overnight facilities frequented by hikers near the A.T.

Typically norovirus occurs only when and where there is very heavy overnight hiker traffic with poor hygiene and inadequate Leave No Trace practices being employed.

Outbreaks of norovirus, or ("stomach bug" when not confirmed) have been reported on the Appalachian Trail in recent years, disproportionately occuring in the northbound thru-hiker bubble in the South. Most often hikers have gotten sick between Hot Springs and south of the Virginia border. Testing itinerant backpackers is challenging, but the year of the biggest outbreak (2014) a high percentage (or almost all, I can't remember now) of the hikers with stomach bug symptoms (both projectile vomiting and diarrhea are the signature ones) tested by the Tennessee Dept. of Health had norovirus. There was also an outbreak in northern New Hampshire/southern Maine a several years back (reportedly when the nobo and sobo bubbles were colliding). There was also an confirmed outbreak in central Virginia, long enough ago that the term "Norwalk virus" was used by the health dept. There may have been other outbreaks.

Here's the language about norovirus from the ATC website:


Norovirus, a highly contagious stomach virus, is transmitted by contact with an infected person, contaminated food or water, or contaminated surfaces, and it is easily spread on parts of the A.T. that experience crowded conditions. Norovirus causes your stomach and/or intestines to become inflamed, which leads to stomach pain, nausea, and diarrhea.

The virus has a 12- to 48-hour incubation period and lasts 24 to 60 hours. Infected hikers may be contagious for three days to two weeks after recovery. Outbreaks occur more often where people share facilities for sleeping, dining, showering, and toileting; the virus can spread rapidly in crowded shelters and hostels; and sanitation is key for avoiding and spreading norovirus.

Take the following steps to prevent contracting and spreading the illness:


Do not eat out of the same food bag, share utensils, or drink from other hikers' water bottles.
Wash your hands with biodegradable soap (200 feet from water sources) before eating or preparing food and after toileting.
Be aware that alcohol-based sanitizer may be ineffective against norovirus.
Treat all water. To learn best how to treat your water, click here (http://www.cdc.gov/healthywater/pdf/drinking/Backcountry_Water_Treatment.pdf) for information from the CDC.
Follow Leave No Trace guidelines for disposing of human waste.
For important prevention tips and information about how to report norovirus on the Appalachian Trail, click here (http://www.appalachiantrail.org/docs/default-source/Hiking-Basics/poster-prevent-norovirus-2016-(2-12-2016).pdf?sfvrsn=0).
For more information, click here (http://www.cdc.gov/norovirus/).


The CDC advises that a combination of filtration and chemical treatment is the most effect method of treating water in the backcountry (other than boiling). Here's a page with good information: A Guide to Drinking Water Treatment and Sanitation for Backcountry & Travel Use (http://www.cdc.gov/healthywater/pdf/drinking/Backcountry_Water_Treatment.pdf). (Highlighting this link again here, in case you missed it above).

Or you can go straight to the Backcountry Water Treatment Chart (http://www.cdc.gov/healthywater/pdf/drinking/Backcountry_Water_Treatment.pdf) that rates effectiveness of different methods.

Laurie P.
ATC

Offshore
09-05-2016, 09:59
That assessment is based not so much on "might you contract a viral infection" as "might you contract a life-threatening viral infection." The US has very little poliovirus, coronavirus, or hepatitis A in the population, so it's vanishingly unlikely that you'd encounter them in the field. BK virus and JC virus (the commonest polyomaviruses) are generally not dangerous, or indeed even noticeable, to immunocompetent people (if you're HIV positive, a transplant recipient, or a chemotherapy patient, the balance shifts). That means that the worst you're likely to get from contaminated water would be norovirus, coxsackievirus, or rotavirus. While those can all have you wretchedly ill for a few days, they're unlikely to be dangerous to an otherwise healthy adult.

Nope - you are attempting to set best practices based on your own risk tolerance - which is fine for yourself, but irresponsible to extrapolate to the trail user population as a whole. (Kind of like those self-proclaimed experts that say sleeping with their food in bear country is fine because they never had a problem themselves.) The adage is based on whether a virus is present in untreated water and if you stand a significant risk of contracting it through exposure to untreated water. As you said in your own post, a virus' potential for harm is a function of the virus itself and the medical/physiological characteristics person exposed to it. Besides, I don't need to die from a virus to have it ruin a trip. You don't need to be afraid out there, but you don't need to be foolish, either.
as

Another Kevin
09-05-2016, 12:16
Nope - you are attempting to set best practices based on your own risk tolerance - which is fine for yourself, but irresponsible to extrapolate to the trail user population as a whole. (Kind of like those self-proclaimed experts that say sleeping with their food in bear country is fine because they never had a problem themselves.) The adage is based on whether a virus is present in untreated water and if you stand a significant risk of contracting it through exposure to untreated water. As you said in your own post, a virus' potential for harm is a function of the virus itself and the medical/physiological characteristics person exposed to it. Besides, I don't need to die from a virus to have it ruin a trip. You don't need to be afraid out there, but you don't need to be foolish, either.
as

I think you misunderstand me. We may be in 'violent agreement' here. I always treat water, generally with chlorine dioxide, which is quite effective against viruses, and moderately effective against protozoa given adequate contact time. (Protozoal disease would ruin a trip only if it's a longer trip than I ordinarily take, because of its long incubation period.)

If there's no risk of the filter freezing, I'm willing to use filtration instead, trading near 100% elimination of protozoa for the risk of viral infection. In real winter, I mostly resort to boiling. If I'm going to have to melt my drinking water anyway, I might as well boil it.

I'd go back to Aqua Mira in the thru-hiker bubble, but I'd try to avoid the bubble in any case. Most of that is personal preference - I'm Out There to escape crowds. Still there's likely to be aerosolized norovirus about the shelters, hostels and campsites, and most surfaces that hikers handle (wood piles, outhouse doors, register books, that tree branch you use to pull yourself up the streambank) are likely to be contaminated during an outbreak. I'll say that there's elevated risk from the water sources when there's an outbreak going on, but stand by my contention that hand washing is even more important.

In any case, it's important to treat water with something, to knock out nasties like Shigella, which is pretty common and quite unpleasant indeed.

For broad effectiveness against both protozoa and viruses, you'd really need to use both a chemical method and a mechanical method, or else use UV. I don't trust the Steripen - I've seen too many malfunction in the field. Very few hikers routinely use two methods of water disinfection. With frequent hand washing and the use of at least one method, the risks are already pretty low.

In any case, the most important disinfectant is soap and water. There was at least one retrospective study that polled AT hikers close to a norovirus outbreak about their sanitary technique and their GI outcomes. Self-reported frequent hand washing was the strongest correlate with rate of infection.