Harnessing the sun to kill Cholera

This is my final post for today, I've been digging the Inet relentlessly for the whole day!
But this one is a good one- It's possible to sterilize water from bio-infectants, by putting it in plastic bottles in the sun.
Ofcourse plastic bottles are not very healthy after they've been in the sun, it's a known fact. But on the other hand, it's better than no defence against Cholera, which is many times the case.
Just note that the water is probably better disinfected when they're clear, cause otherwise the dirt/algea/whatever blocks the sun UV rays from entering.
Glass is not a solution- as it filters UV rays.
Leaving an open container is probably a possible solution as well, but then it's open for contaminants coming from the outside, and care should be taken for animals etc. not taking a sip or dipping inside.

http://news.bbc.co.uk/2/hi/africa/4786216.stm

Colloidal Silver

Info about Colloidal Silver, Which, mixed in water, can kill the bacteria and microorganisms residing in it, such as Vibrio Cholerae.
There are also Do it yourself instructions at the lower part of the page, using Batteries and silver wire (but where do you get a silver wire??)

A call for Mindstorming- Affordable Cholera prevention!

Filtering Cholera with old sari- the original article
A great article, that probably saved a lot of life,

http://www.pnas.org/content/100/3/1051.full

I hope to spread and use this knowledge in Zimbabwe, to help the locals avoid Cholera by using affordable and common matereals.
Anyone with an Idea how to improve this method is VERY invited to comment and share his/her ideas here.
Has anyone an idea how to harnass Ultra Violet (UV) rays for aid in annihilation of the bacteria?
I thought about somehow using the sun, but have yet to find a cheap and affordable method for resourceless places like many poor areas in Zimbabwe and elsewhere in the world.

UV filteration project for contaminated wells in Mexico

A great project, very inspiring!

http://www.niparaja.org/cubetauv/english/index.htm

Solar Disinfection

Solar Disinfection

A very simple and inexpensive solar disinfection process consists of simply filling clear plastic bottles with source water. The bottles are then placed on a sunlight-reflecting surface such as aluminum or corrugated iron sheets, possibly on a roof. These bottles are exposed to direct sunlight for anywhere from one hour to two days, depending on the conditions. The Sun’s rays work to kill microorganisms in water by irradiation with ultraviolet (UV)-A rays and also by raising water temperature to 50 degrees Celsius or higher.

Solar disinfection, does not, of course, treat chemical water quality problems such as arsenic, heavy metals, pesticides, etc. It also requires relatively clear water, because suspended materials and the natural color in water block the UV rays. Bottles larger than one or two liters should not be used, which limits the quantity of water that can be treated. And it is not recommended for days of continuous rainfall. However, it has potential to greatly reduce incidences of diarrhea and dysentery, and to minimize the terrible public health toll that they exact worldwide.

http://www.drinking-water.org/html/en/Treatment/Membrane-Processes-technologies.html#tech1

Optimal method of cloth filtering

Optimum effect

The researchers found the optimum filtering effect when the sari fabric was folded so that the water passed through four layers of cloth. In laboratory tests, this removed more than 99 per cent of the cholera-causing bacteria, Vibrio cholerae. The bacteria themselves are tiny, but they cling to plankton that are too big to squeeze through the pores of the fabric.

The study showed that in practice this filtering reduces infections. The rate of new cholera cases in the 27 villages asked to filter water through saris was half that seen before the trial. And many of the cholera cases detected were traced to visits to communities not participating in the project.

Old clothes were more effective filters than new, because the fibres had slightly unravelled and this made the holes smaller. The cloth filters cut cholera cases as effectively as more expensive nylon filters designed to trap worm larvae, supplied by the World Health Organization.

Also encouraging, says Colwell, was the villagers' response to the educational program. Once they were shown the bugs swimming around in the untreated water, they quickly realised the importance of filtering.

Precious fuel

However, Robert Quick of the US Centres for Disease Control and Protection told New Scientist: "Our concern is that it won't eliminate all contamination and people will still be at risk. We would recommend that people clean the water with chemicals, or boil it."

He has worked with the World Health Organization to develop the "safe water system", under trial in 15 countries. Filtering is only the first step of their system.

But in the regions of Bangladesh where the NSF has been working, disinfecting chemicals are hard to come by and there is so little wood that dried cow-dung is their only fuel, too precious to waste boiling water. Under such circumstances filtering water through old clothes "is, of course, better than nothing" says Quick.

Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0237386100)

http://www.newscientist.com/article/dn3258-old-clothes-filter-out-cholera.html

A research about filtering out Cholera with cloth

Forcing water through a simple filter made from the cloth of old saris can reduce cholera cases by about half, according to a study of rural villages in Bangladesh where cholera is a major health problem.

Researchers suggest that the sari filters may also reduce other gastrointestinal illness.

The study, appearing this week in The Proceedings of the National Academy of Sciences, compared the effects of filtering pond or river water through modern nylon mesh and through old, much-washed sari cloth and found that the sari solution was better.

''Sari cloth is cheaper, and we found that it is much more effective than the nylon mesh,'' said Dr. Rita R. Colwell, a professor of microbiology at the University of Maryland at College Park, an author of the study. ''The nylon costs only a few dollars a year, but a few dollars can be a week's wages in these Bangladesh villages.''

Dr. Colwell said researchers had discovered in laboratory studies that most of the cholera bacteria in ponds, rivers and other standing water was attached to the gut of a copepod, (pronounced KO-puh-pod), a type of tiny zooplankton found in standing water.

When people drink unfiltered water, she said, they swallow the copepods and introduce cholera bacteria into their systems. As the germ multiplies, it releases a toxin that causes extreme diarrhea and cramping.

Filtering the copepod, Dr. Colwell said, reduced the cholera rate by at least half. She said there was also evidence that other germs were removed because women in the villages with sari-filtered water said there was less diarrhea and other digestive problems.

In modern hospitals, cholera is easily controlled, but without treatment it kills 50 to 80 percent of those infected. It is most lethal for children under 5 and for the elderly.

Dr. Colwell noted that the rural Bangladesh villages where the filter system was tested are many hours from good medical care.

Dr. John Mekalanos, a cholera expert at the Harvard Medical School, said Dr. Colwell and her co-authors ''have made a major contribution to the control of cholera'' by demonstrating an easy way for rural third world people to protect themselves from a major health problem.

''It could make a big difference in the region and elsewhere in the world,'' Dr. Mekalanos said.

http://query.nytimes.com/gst/fullpage.html?sec=health&res=9902E6D61531F937A25752C0A9659C8B63