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#120078 - 08/30/09 01:06 PM Re: leptospirosis filter [Re: Dryer]
Fiddleback Offline

Registered: 06/22/04
Posts: 478
Loc: Northern Rockies
All collies are dogs but not all dogs are collies. We'll have to agree to disagree on the word usage of "sodium hypochlorite." grin

The takeaway from below is; 1)ClO2 is more effective than chlorine and its 'bleach' version, 2)while new to backpackers, ClO2 is time tested and, 3) the same can be said for UV treatment.

The water that emanates from water utilities is used/approved for irrigation, human consumption, dumping into surface waters or a combination of all three. Different standards/regulations are involved for the different uses. Municipal water providers generally use a multi-step process which includes sedimentation, biologic breakdown of the waste, filtration and chemical treatment. UV treatment is also being added.

As for municipal utilities trending to the use of chlorine dioxide:

U.S. municipal water systems started using chlorine dioxide in the mid-40’s (Treatment of Drinking Water with Chlorine Dioxide, The start time in Europe was about the same. But ClO2 is not without its own problems to include cost, handling safety, and by-products. Still, because of chlorine’s more troublesome human health issues and the subsequent changes in water quality regulations/standards, utilities have turned to ClO2 (ibid). “It is recognized as a superior water disinfectant alternative to chlorine and has become increasingly popular as a water purification treatment. Chlorine is being phased out due to growing concerns over its carcinogenic by-products, principally trihalomethanes (THMs)…In the U.S., the Safe Drinking Water Act and its subsequent amendments over the last 20 years have required dramatic improvments in the quality of municipal drinking water. These stringent new requirements have increased the use of chlorine dioxide in the U.S. while decreasing the use of chlorine as a water treatment chemical.” (Chlorine Dioxide – Water Treatment Technical Report: Chlorine Dioxide as a Water Purification Product and Safe Water Treatment Chemical, More than 15 years ago, the trend was well established, “Approximately 700 to 900 public water systems use chlorine dioxide to treat potable water (Hoehn, 1992).” (EPA Guidance Manual, April 1999 Alternative Disinfectants and Oxidants, 4.pdf) That trend continues despite the moribund character of utilities. Here in Missoula County, our less-than-stellar (and often, less-than-compliant) wastewater treatment plant has, I think , adopted ClO2 treatment. I know that was the plan which also included the addition of UV treatment and that addition has been accomplished. Virtually all the sources here and others I saw specified giardia when referring to the higher effectiveness of ClO2.

"...inalienable rights...include the right to a clean and healthful environment..." Montana Constitution

#120091 - 08/30/09 09:02 PM Re: leptospirosis filter [Re: Dryer]
Rick_D Offline

Registered: 01/06/02
Posts: 2802
Loc: NorCal
So far I've only found a U.S. reference to Niagara Falls, New York as using ClO2 municipal treatment. I presume there are others but it's clear that it hasn't been widely adopted. In California, several very large systems have switched to chloramine, which is much more stable and persistent in the distribution system than chlorine, but presents its own set of problem byproducts, plus it's quite toxic to aquatic life. And it's green.



#120100 - 08/31/09 09:47 AM Re: leptospirosis filter [Re: Dryer]
ringtail Offline

Registered: 08/22/02
Posts: 2296
Loc: Colorado Rockies
My municipal water is safe after sand filtering. The chlorine is added to keep it potable in the tranmission system. Water in the system, especially fire hydrants, can get stagnant
"In theory, theory and practice are the same. In practice, they are not."
Yogi Berra

#151892 - 06/25/11 09:49 PM Re: leptospirosis filter [Re: mantashrimpman]
mantashrimpman Offline

Registered: 08/26/09
Posts: 4
Loc: honolulu
haha ok guys so the consensus for me not to contract leptospirosis on my next backpacking trip would be to chemically treat the water? kalalau valley in kauai is known for having problems with lepto and i was looking for a way to filter without having to make the water taste bad with chemicals. But if there is no other way, drinking water that doesn't taste spectacular is still better than getting flu like symptoms 11.2 miles away from my car.

#151959 - 06/27/11 01:54 PM Re: leptospirosis filter [Re: mantashrimpman]
Heather-ak Offline

Registered: 07/11/10
Posts: 597
Loc: Fairbanks, AK

Boiling water
The bacteria (and almost all other pathogens likely to be found in rivers and lakes) are killed by boiling the water for a few minutes - so this works best on small volumes that you wanted hot to begin with. Boiling is the first choice for camping trips and also means that food cooked at or above boiling point (such as meat) will also be rendered safe in the process. It of course needs a power source, but it doesn't involve chemcials so is acceptable to people wanting the least impact on their diet. Boiling is not an option for a general household water supply, but of course makes boiling water for hot drinks safe.

Iodine tablets
Water purification tablets that use iodine are very effective too, and don't need a heat source, but can leave a taste that some people find unpleasant. They are however easy to use and light to carry, so are ideal for long hikes and expeditions to remote areas. It's not an option for large volumes or a household supply.

UV sterilisers
These are also very effective against leptospira (and most other pathogens), and can be bought on all scales. Permanent systems for processing flowing water in a domestic house are available, but can be expensive and use electricity. Portable devices for camping and backpacking are also available, resembling a small flashlight or pen, and these can be used to sterilise a single cup of water - but need batteries. The advantage of using UV is that there are no chemicals involved, and the electricity required is less than for boiling the same volume. It does require the sample to be transparent though, so can't be used on things like milk.

Water not used for drinking - such as swimming pools and ornamental features, can be protected by adding dissolved chlorine. In commercial pools this is a complex engineering process, but for private pools it's usually added in the form of tablets. It's important to keep the chlorine levels high enough to be effective but not too high, so testing kits (using color-changing paper) are available. Leptospirosis is killed by the concentrations of chlorine used in commercial pools and most private ones, assuming the owner follows the instructions on the packet!

Filtration - does not work!
Leptospira are incredibly small - they can pass through the pores in water filters, even those that claim to remove bacteria. They will pass easily through filters with a pore size of more than 0.2 micron, including membrane and charcoal types. High-pressure laboratory filters with a pore size of less than 0.1 micron will block them, but the typical hand-held water filters used by hikers, pool filters and the fitted cannisters used in some domestic kitchen applicanes are useless at removing leptospires - they are often used to separate leptospires from other bacteria when preparing samples for research, as the leptospires pass through but other bacteria don't!

#151967 - 06/27/11 03:17 PM Re: leptospirosis filter [Re: Heather-ak]
OregonMouse Online   content

Registered: 02/03/06
Posts: 6489
Loc: Gateway to Columbia Gorge
Originally Posted By Heather-ak

Iodine tablets
Water purification tablets that use iodine are very effective too, and don't need a heat source, but can leave a taste that some people find unpleasant. They are however easy to use and light to carry, so are ideal for long hikes and expeditions to remote areas. It's not an option for large volumes or a household supply.

OK, time for my periodic rant about iodine. My own experience is that after a month of use (only on weekends) I developed an all-over rash consisting of deep lesions (lichen planus) that left permanent scars. To this day I still cannot eat anything with even trace amounts of iodine. That means no seafood, no food prepared with iodized salt (which means most restaurants and most food prepared in peoples' homes are out), nothing with added iodine. Until very recently, it meant I could never have an angiogram (there are now alternatives available).

I found that this allergy or sensitization or whatever you want to call to iodine it is not at all uncommon. I wouldn't wish this condition on my worst enemy!

Per the Centers for Disease Control:
Iodine has physiologic activity (it is used by the thyroid), so WHO recommends limiting iodine water disinfection to a few weeks of emergency use. It is not recommended in persons with unstable thyroid disease, known iodine allergy, or pregnancy (because of the potential effect on the fetal thyroid).

More from the CDC (same article as above):
some common waterborne parasites such as Cryptosporidium, are poorly inactivated by halogen [iodine and chlorine bleach/sodium hypochlorite] disinfection, even at practical extended contact times.

I strongly recommend never using iodine! Chlorine dioxide tablets are much safer, kill all bacteria and viruses, and kill protozoans given sufficient contact time. Used in conjunction with a filter of 1.0 microns or smaller, chlorine dioxide plus flitration is by far the safest method other than boiling.

IMHO, any source that recommends using iodine for water disinfection and doesn't even mention chlorine dioxide is very poorly informed.

Edited by OregonMouse (06/27/11 03:23 PM)
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey

#151972 - 06/27/11 04:02 PM Re: leptospirosis filter [Re: OregonMouse]
Rick_D Offline

Registered: 01/06/02
Posts: 2802
Loc: NorCal
Can't stand the stuff (iodine) myself--smells like an emergency room, not something I want to drink.

For peace of mind, i'll recommend either UV or one of these:

Sawyer 0.02 µm filter


#158382 - 12/07/11 03:17 AM Re: leptospirosis filter [Re: Rick_D]
mantashrimpman Offline

Registered: 08/26/09
Posts: 4
Loc: honolulu
what about the msr miox? will this purifier be effective against the leptospirosis virus?

#158385 - 12/07/11 08:52 AM Re: leptospirosis filter [Re: mantashrimpman]
Paulo Offline

Registered: 01/27/11
Posts: 158
Loc: Normally Pacific Northwest
Sawyer does a virus filter!
Without a doubt, the hardest thing of all in a survival situation is to cook without the benefit of seasonings and flavourings. - Ray Mears

#158419 - 12/07/11 07:43 PM Re: leptospirosis filter [Re: mantashrimpman]
CamperMom Offline

Registered: 01/04/02
Posts: 1201
Loc: Eastern MA, USA
I hadn't even heard of leptospirosis and just did a quick read. It is present in animal populations, infecting small numbers at a time. It seems to more common in tropical areas, but with the modern world's convergent paths, it has spread. There have now been human cases reported in Massachusetts. Oh, happy days!

As I said, I just did a quick read. Leptospires are spirochetes, not a viruses, in case anyone really cares. I think in my 40+ year old textbooks, they may have been written up as not bacteria, Maybe because of the flagella, like protozoans have. I see they are classified as a spiral bacteria. Besides Leptospirosis, spirochetes are responsible for Lyme disease and Syphillus. Yea!

I think I am going to continue to treat water collected along the trail...


#158440 - 12/08/11 10:55 AM Re: leptospirosis filter [Re: mantashrimpman]
Steadman Offline

Registered: 09/17/09
Posts: 511
Loc: Virginia

Oh, that sounds like a great trip. When I move home again, I want to do that hike.

Everything proposed will work to keep leptospirosis out of your drinking water.

- A backpacking filter will work.

- Chemicals (bleach, chlorine dioxide tablets, and iodine) will work if you follow the directions and mind the amount of exposure time of the chemicals to the water.

- Boiling your water will work.

- A UV purifier will work.

If you really want to be cautious, combining two methods (filtering and then using chemicals is the most common combination) will work but you will have to carry more stuff.

Leptospirosis is a problem in all fresh water in Hawaii. If you ever went swimming at the swimming hole off the Dupont trail in Tantalus, or jumped off of Mauanawili Falls, you risked exposure. The good news is that you live in Hawaii, and the docs know what leptospirois symptoms look like.



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