Giardia Outbreak

[Andy F]

Mitchell,

Sorry to hear about your bad experience.

Would you mind detailing how long you waited to drink the water after putting the chlorine dioxide pills in and an estimate of how cold and cloudy the water was?

[mitchell Keil]

To those who are not doctors on this thread: Flagyl IS an antibotic. It's generic name is metronidazole and it is used to treat anaerobic bacterial infections, ameobic and protozoan parasites of which giardia is one. The course my doc prescribed is a 7 day course 12 hours apart for each dose taken with food. It has not left me feeling worse than dead.(In fact I have felt just fine taking it.) I take massive doses of acidolphilus to counteract the effects on the flora in my intestinal tract. I have been told by him that in mild cases, which mine appears to be (since I appear to have had a period of time in which I felt fine and was symptom free,)that I can look to a complete recovery and no relapses in the future. I guess time will tell.

And I have heard that it can be contracted by the simple act of washing my face and getting it into my eyes or nose. Remember, it only takes a couple of cysts to contract the infection.

So a word to the wise: treat your water as I have done and if washing in stream water treat it, too. In fact treat all water you encounter including so called "safe" potable water from the taps in campgrounds and at trailheads such as one finds in the Sierras.

And finally, I did start this thread to find out if anyone has seen an uptick in the incidence of giardia in their area as I have and as confirmed by vets I have spoken to in Orange county, Riverside county and Marin county.

And to answer those who wish to know how I treat my water and how long it took to get the symptoms after exposure.

I use the chlorine dioxine pills and have done so since they came out about 5+ years ago. I use one pill per liter and usually wait 15 minutes to 20 minutes before drinking. I also drop a elixir electrolyte tab in at the same time. If the water is really cold, i wait 30 minuutes. I rarely find the water I use to be cloudy or silty.
I will be using the pills from now on in my wash basin and in the water I use to wash my face in.

By my best estimate I contracted the infection about 7 days before I showed any symptoms. I have been told by the doc that I could carry it for anywhere from 24 hours to a month before showing symptoms. It often depends on the vector load one ingests and/or one's natural level of resistence or general health.

[John S.]

This thread seems to be fear mongering over a case of Giardia that is not proven to be from the backcountry.

[Stephan Doyle]

I must need to start filtering my water at work and home, too. No reason to frighten people about "potable" water.

[Randy Cain]

John: "This thread seems to be fear mongering over a case of Giardia that is not proven to be from the backcountry"

Without a RECENT water sample from every single source drank from on any given trip, how could anyone ever prove that giardia was obtained from the backcountry? I doubt most cases are ever proven in such manner but rather treated empirically based on symptoms & suspicion initially and possibly confirmed with stool specimens after the fact. When you describe the symptoms to a doctor, they will inevitably ask you if you have travelled to a foreign country, drank water from a potentially suspicious source, etc. If you tell them that you just returned from a backpacking trip a week ago (incubation period ~ 1-2 weeks usually) and drank from streams, unless there has been a surge of other patients in the area presenting with similar symptoms that would be a clue that the municipal supply is contaminated (ex: 1993 Cryptosporidum outbreak), the doc will suspect that the backcountry water is the culprit. But proof? None whatsoever. So I don't think it's really fear mongering to assume that the source was the backcountry water, when it seems to be the most likely cause, especially since the time to symptom onset falls into the typical incubation period. Just my thinking anyway. :)

[Mary D]

"I use one pill per liter and usually wait 15 minutes to 20 minutes before drinking. I also drop a elixir electrolyte tab in at the same time. If the water is really cold, i wait 30 minuutes."

What temperature was the water? It's quite possible that your wait time for protozoan cysts such as giardia may not be sufficient. Here's a table from the EPA for chlorine dioxide tablets:
http://www.equipped.com/graphics/MP1ChartB299H141.gif
Here's the gist of the table (also found in many other places, such as the Katadyn website and Wilderness First Aid texts):

Cysts Clear water, 20*C [68*F]: 30 minutes // Turbid water, 4*C [39*F]: 4 hours

It would be nice if the EPA would furnish a few intermediate numbers for estimating contact time for conditions between the two! For those of us who backpack in the high mountains, water from springs is likely to be in the 30s F but is usually clear. It's obvious that the 4 hour wait time on the package is the absolute worst case scenario. I once asked Katadyn if they had any intermediate numbers, and they said no, implying, although not actually saying, that the EPA wouldn't let them release such numbers anyway. This leaves us all up a creek (bad pun, I know) on contact time, unless we want always to assume that worst scenario!

Anyway, it is possible that your stream water was cold enough to require a longer contact time, since it was probably colder than 68*F.

It's also possible that the electrolyte tablet might reduce the effectiveness of the chlorine dioxide tablet because it in effect increases the turbidity of the water. You might consider waiting to add the electrolyte tablet until the chlorine dioxide tablet has been in the water for the appropriate treatment time (whatever that is, but probably longer than your 20-30 minutes). I'm inferring (i.e. slightly educated guess) on this one, though.

Without sampling your water source specifically for giardia (normal water tests are for coliform bacteria), specifically at the time you ingested it, we'll never know for sure!

As for the dog outbreaks–we'll probably never know, either. However, if you've ever watched two dogs greet each other, you can easily guess one possible contamination source! In my dog's case, the backcountry exposure was either 4 weeks or 3-4 days before the symptoms, neither of which fits the incubation period. However, he was at the beach, where he has a habit of lapping ocean water, about 10 days prior to symptoms. He also got acquainted with quite a few dogs during that period. Again, we'll never know for sure.

I do assume that my backcountry water sources may be contaminated, so I filter (heavier but faster and better tasting). You never know what's upstream–I've found both live and dead animals, several different times. Even if only 20% of my sources (generally lakes and streams rather than springs) are contaminated, that's more than I want to risk.

Maybe a dog with giardiasis was in the water upstream of where you got your water?? Now that's really in the realm of pure speculation!

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[Kevin Lutz]

Just camped at Devore myself. I always treat that water (UV) because it's not exactly the Sierra and lots of joggers/day hikers (with pets)go through especially on weekends. With that kind of human exposure I would not be surprised if the stream is contaminated. I still don't treat water much in isolated places.

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[John S.]

Hi Randy. My comment was a bit too general..yes. Some of what I saw Mary D has commented on, there seeming to be holes in Mitchell's treatment technique (only 15 minute waits, adding other tablets at the same time as treatment tablets). The other thing is that he said nobody should drink from campsite potable water spigots without treating? Now that seems a bit over the top from a single case of "possible" giardia from the water source he is suspicious of. Sorry for being too general or otherwise inflammatory ; ).

I've never heard, nor can easily find, info on transmission of Giardia through the eyeball. Get an article reference if possible. Getting water in nose (then swallowed) or mouth could certainly get one sick. The CDC website says it can take as little as 10 cysts.

[Inaki Diaz de Etura]

Mitchell, according to your advise we wouldn't be able to swim in the lakes/rivers, neither probably raft, canoe or kayak. In all honesty, nature doesn't work that way. I know this is a tricky issue with few real info and lots of noise but I'd advise you to do some honest research on the real dangers so you can take useful actions and not only placebos. And please don't add up to the noise, there's already enough of it.

[mitchell Keil]

You know one of the reason I left BPL was that the posters get entirely too focused on their own agendas and opinions. That has resurfaced with this thread.

I did have Giardia despite the posts that seem to question that (My course of treatment is finally over today). Really, you are a doctor and examined me to know that I didn't?

My comment about potable sources is certainly a real possibility and only applies to the spigots that we see at TH. Do you really know if it has not been compromised? Haven't you noticed the conditions of the ground around these spigots. Who knows what someone may have left on the spigot itself when they washed their dishes there or cleaned fish there (despite that you are not supposed to). I know they are supposed to be tested but does anyone know how often? And does anyone care to bet on the piping integrity after a winter? And does anyone care to guess how the federal and state budget cuts are affecting the ability of the forest service to monitor these sources?

Although I can't be 100% certain that I got giardia from the particular stream I camped by, I can be almost certain since I did not use any other water than from this source and had not been out for more than a month prior to this hike and had not treated any water to drink in more than 2 months (using only water from home for hikes). That pretty much limits my exposure vector don't you think?

Perhaps I could increase the time to drink after dropping a pill into the container and perhaps it does compromise effectiveness by also dropping in a hydration tab. But I have been doing this for 5 years without a problem. And I have seen nothing in the literature that would indicate that the hydration tabs which do not cloud the water have any adverse effect. If time to effectiveness is a problem then perhaps I should switch to a SteriPen approach. Waiting more than 30 minutes for the pills to work is a bit more than I want to wait, and if it is even longer for cold water, what's the point of using them? How religiously do any of you who use the pills wait the full 30 minutes or much longer for cold water? Let's get real on this.

Since it takes so few cysts to create a real health problem why not err on the conservative side and treat all water you drink? If you swim, raft, kyak or tube in wilderness water, what risks do you run? I don't know. How you limit your exposure to water borne vectors is your business and perhaps it is just a risk one runs to enjoy the natural wonders of our country. But it is a risk however quantified.

My initial question has only been addressed by a very few posters. I wonder why.

[Stephan Doyle]

http://www.sierranaturenotes.com/naturenotes/Giardia.htm

An interesting quote: "Recall that San Francisco water can contain a concentration of 0.12 cysts per liter,24 a figure now seen to be higher than that measured anywhere in the Sierra. San Francisco city officials go to great lengths to assure their citizens that the water is safe to drink, and if true—as it most assuredly must be—this comparison alone is quite revealing."

To the OP, you were the one that started with your own "agendas and opinions." Based on scientific data, there is no need for you to push this obsessive fear of (even potable) water. Offer up your experience, share what happened to you, but don't get upset when others defend how safe backcountry water typically is when caution is exercised. There are many more (likely) possibilities than you alluded to.

[Tad Englund]

Mitchell, I don't know or care how your were infected, but I do care that you did get infected.
What a literal pain in the butt!
Thanks for sharing.

Tad

[Jerry Adams]

Yeah, thanks for the info Mitchel

Even though there's no clear scientific answer. Very confusing that you tested positive for Giardia yet treated all your water.

[Stephen Barber]

"Waiting more than 30 minutes for the pills to work is a bit more than I want to wait, and if it is even longer for cold water, what's the point of using them? How religiously do any of you who use the pills wait the full 30 minutes or much longer for cold water? "

That's a big reason why many folks use Steripen or filtering instead of chemicals.

Back in the old days when I used iodine to treat my water, I always carried two Nalgenes. Bottle A, my drinking bottle, had water which had been treated more than 30 minutes before, at the next to the last water source. Bottle B, the treatment bottle, had fresh water from the last water source plus iodine. Hopefully Bottle A was about empty when I got to the next water source, where I refilled it and added iodine, and Bottles A and B would switch roles. That way I always had warm, nasty tasting – but clean – water to drink!

I love my Steripen!!!!

[Nick Gatel]

I try to plan my water sources just in time. Once there, I cook a meal which boils some of the water and chemicals go into the rest. Other times, I will be drinking the last of my water at the source, and there is time to wait for the rest to work with the pills.

Never owned a filter or other heavy mechanism that might malfunction :)

[Greg F]

Did you drink any non municipal water supplies in the last month. I got crpyto when i was a kid from farm well water that was contaminated and was just using a sand filter.

I am debating quiting treating water, i certainly dont hit the required wait times for clo2 tablets. Might just get a sawyer squeeze for lakes.

[Jeremy and Angela]

It would be nice if the EPA would furnish a few intermediate numbers for estimating contact time for conditions between the two! For those of us who backpack in the high mountains, water from springs is likely to be in the 30s F but is usually clear. It's obvious that the 4 hour wait time on the package is the absolute worst case scenario.

A good rule of thumb for chlorine dioxide (ClO2) would be to double the time for each 10° C decrease in temperature. As the Katadyn chart suggests 30 minutes for clear water at 68° F, that would indicate a one hour treatment time for 50° F water. This assumes, of course, that there is no padding that built into that 30 minute time.

Note also that ClO2 will also react with organic matter in water, lessening its effectiveness.

Ref: (relevant content starts around page 646)
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA449339

[Mary D]

If you can't or won't wait for the chlorine dioxide pills to do their job (those cysts are hard to kill!), I strongly recommend using another method. Giardia cysts are less resistant to chemicals than cryptosporidium cysts, but not much. There is a good reason for those long wait times, as you've recently discovered the hard way. See Jeremy's link just above.

Not all filters are heavy and clunky. My homemade gravity filter (using a Katadyn Hiker Pro replacement filter and vaguely based on the now defunct ULA Amigo Pro) weighs 6.6 ounces, which is far less than the weight of an extra liter of water undergoing chemical disinfection. During a 5-minute break I can filter a liter of water, drink half of it, and carry only the other half liter. The water tastes better, too! Of course this weight comparison is valid only where there are frequent water sources, but that's mostly the case where I backpack. If you normally go all or most of the day without water sources and have to carry two liters anyway, the weight advantage of course goes to the chemicals.

For more info on various MYOG gravity filters, go here–there are several versions:
http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=8994
Mine is the one that starts well down on page 2, in the post by Cola Vaughan. (Cola, if you're reading this, thank you!) No moving parts to break and no pumping.

I haven't used the Sawyer squeeze filter but have heard good things about it. It weighs half as much as my gravity filter system, so I plan to check it out.

[Jeff J]

is that my 9 oz gravity filter is completely justified. Also, doubles as my hydration bladder.

I agree with Mary (and others) above. If one does not wait the necessary time for chemical treatment to work, why use any treatment at all? May as well forgo the 2 oz of chemicals and tiny vials. This is BPL after all.

-Jeff

[Bob Gross]

"If one does not wait the necessary time for chemical treatment to work, why use any treatment at all?"

You can do the chemical treatment and then rush the wait time. It still may be effective, but you are taking a much bigger risk. It is all a compromise.

FWIW, I use a gravity filter with a 2L Platypus above and another 2L Platypus below. Then, if I want to reduce risk further, like if the water looks bad, then I have a small amount of chemicals to use for overnight wait.

–B.G.–

[john hansford]

Thank you Jeremy for that reference. I have been wading through it, and although dated 2006, it contains a lot of current devices.

Interestingly, it scores Aqua Mira lower than Micropur despite both being based on ClO2, although both are deemed adequate (pages C-71, E-59-3, E-60-3). However, they use the products as instructed by the manufacturers, and a 30 min wait time is specified for AM, but 4 hrs for Micropur, despite similar concentrations of ClO2 being produced. I wonder whether Micropur would compare as well as AM with only a 30 min wait? Probably the test will never get done (or Katadyn will never tell us). For cryptosporidium it says wait 4.5 hrs with AM if <10'C.

[Jeremy and Angela]

There's a specific discussion of both Micropur (p 488) and Aqua Mira Drops (p 494); It appears that the main differences were that test data was available for Micropur, and that the manufacturer instructions for the drops specified only 30 minute disinfection time (that's why crypto wasn't checked off in the charts). They do note in the discussion that the drops are likely effective against crypto if you extend the wait time to 4.5 hours, similar to with Micropur.

(So, it looks like more of a "paperwork" difference.)

[James Marco]

Filtering, chemical treatments, UV treatment, or boiling.
All have good points and bad points.

Chemicals (chlorine dioxide, iodine, bleach to name a few) don't work on all everything. They are all based on some statistical measurment. Even following directions you can become infected. They DO NOT WORK on some tapeworms.

Filters dont work on everything. Again, ststistically based unless you get a good fine filter, then they are too slow for any camping.

Boiling works on anything except chemical contaminants. It *may* make these worse and adds to fuel usage.

UV is supposed to scramble DNA, again statistical.

So, really, you just rely on your body to deal with the large amount of bacteria and parasites present in any water. I would not worry too much about it. Use whatever you like and do the best you can.

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