Cholera cure? You're wearing it

The solution to one of the world's biggest killers has come from an absurdly simple source - the sari. Peter Coles reports

For developing countries, the problem with diseases is rarely that of identifying them. It's not even discovering a cure. It's finding the money to pay for that cure, and to make the changes in infrastructure that will prevent the disease maintaining an epidemic, or endemic, status.

Cholera is a case in point. In Britain, this once-feared disease is now almost unknown, banished by the separation of sewage and supply lines after its cause - polluted water - was identified in Victorian times. But that required a huge investment in our sewerage system. In countries such as Bangladesh and parts of South America, the disease remains an ever-present danger.

There, the idea of vaccination is uneconomic. The present vaccine has, in any case, only a 50 to 60 per cent effectiveness in reducing clinical illness for a maximum of six months, and primarily in the first two months after vaccination. It has also been shown to be of no benefit in controlling the spread of disease.

Instead, it needs a bit of lateral thinking to find a solution. Amazingly, it seems that a team of scientists, led by Rita Colwell from the University of Maryland, in the United States, and the International Centre for Diarrhoeal Disease Research in Dhaka, Bangladesh, has achieved the ultimate: a cost- free method of preventing the disease. The answer: clothing - saris, to be precise. Anyone who wears a sari, or knows someone who does, has the required technology to provide water that is virtually guaranteed not to lead to cholera, at any time.

The route to their solution requires an understanding of the microorganism and processes that leads to cholera. The bacteria that cause it - known as vibrios - are drunk along with contaminated water. Once in the gut, they release a toxin which causes severe diarrhoea and vomiting. This leads to the sufferer becoming severely dehydrated and, in many cases, it causes death.

Professor Colwell and her colleagues made a study of the biology of the bacterium. They found that the bacteria normally live in the gut of tiny plankton-like organisms known as copepods. Each copepod carries thousands of cholera bacteria; drinking only a handful of these, carried in dirty water, could cause the disease. And that happens with regularity. Plankton blooms occur in spring and autumn in Bangladesh, and each bloom is invariably followed by an outbreak of cholera.

Sterilising the water by boiling seems an obvious preventative measure - but it fails the economic test. Wood for fuel is too scarce in Bangladesh.

The scientists therefore turned their thinking around. Rather than killing the copepods and bacteria once they are in the water that the person intends to drink, why not find a way to remove them before drinking? Tests of water samples from Bangladesh showed that filtering out the copepods would remove the bacteria.

In fact, they discovered that filtering water through four layers of sari material reduced the number of cholera vibrios by more than 99 per cent - dramatically reducing the chances of consuming a dose large enough to cause cholera. Four layers of cloth turned out to be the optimum number: more led to clogging of the filter but no improvement in efficiency. "This method should save many lives," says Professor Colwell. This is especially true after the plankton blooms, when the risk of an epidemic is highest.

Sari material is just as good as - or better than - other materials for filtration. This was important, say the team, as it can be found in every household in Bangladesh. "This means that it is affordable even to the poorest of the poor."

But won't the sari material become contaminated? Again, the economic argument is no problem. Decontaminating the material is free: two hours in direct sunlight (a commodity not in short supply in the tropics) is sufficient to kill off the bacteria trapped in the material. In the monsoon seasons, cheap disinfectants can do the trick.

Preliminary field trials will begin next year to ensure that villagers will use the method correctly. This will be followed by a two-year study to compare the incidence of cholera between several villages using the new technique and those that do not. If, as expected, it is a success, then the method will be publicised throughout Bangladesh.

It might seem surprising that such a simple, effective remedy has never been produced by the techniques that have produced so much other folk wisdom. Yet it is clear that an understanding of cholera's particular biology is required, along with some way of measuring the effectiveness of the filtration technique. And because it would not work during monsoon (because the decontamination would often fail) it would be the sort of experiment in folk wisdom which would quickly fall into disrepute.

Thus, although the procedure is a simple one, it has taken many years of research to produce. Because the tiny bacteria are attached to the much larger plankton, they can be filtered out - but no one realised this until the Maryland team's work.

All the hard work should soon pay off. As Professor Colwell comments: "If this simple and direct approach can reduce the number of cholera cases - and especially death caused by cholera vibrio - then we will be very pleased to have made a contribution to the improvement of the health and welfare of our fellow human beings."

It's just that it's not often you can do this by using somebody's clothes.

Suggested Topics
Start your day with The Independent, sign up for daily news emails
ebooksAn introduction to the ground rules of British democracy
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Client Manager

£27000 - £35000 per annum: Recruitment Genius: A growing, successful, friendly...

Recruitment Genius: Property Negotiator - OTE £20,000+

£16000 - £25000 per annum: Recruitment Genius: This family owned, independent ...

Recruitment Genius: Sales Administrator - Spanish Speaking

£17000 - £21000 per annum: Recruitment Genius: This is a fantastic opportunity...

Recruitment Genius: Sales Administrator - German Speaking

£17000 - £23000 per annum: Recruitment Genius: This is a fantastic opportunity...

Day In a Page

The Greek referendum exposes a gaping hole at the heart of the European Union – its distinct lack of any genuine popular legitimacy

Gaping hole at the heart of the European Union

Treatment of Greece has shown up a lack of genuine legitimacy
Number of young homeless in Britain 'more than three times the official figures'

'Everything changed when I went to the hostel'

Number of young homeless people in Britain is 'more than three times the official figures'
Compton Cricket Club

Compton Cricket Club

Portraits of LA cricketers from notorious suburb to be displayed in London
London now the global money-laundering centre for the drug trade, says crime expert

Wlecome to London, drug money-laundering centre for the world

'Mexico is its heart and London is its head'
The Buddhist temple minutes from Centre Court that helps a winner keep on winning

The Buddhist temple minutes from Centre Court

It helps a winner keep on winning
Is this the future of flying: battery-powered planes made of plastic, and without flight decks?

Is this the future of flying?

Battery-powered planes made of plastic, and without flight decks
Isis are barbarians – but the Caliphate is a dream at the heart of all Muslim traditions

Isis are barbarians

but the Caliphate is an ancient Muslim ideal
The Brink's-Mat curse strikes again: three tons of stolen gold that brought only grief

Curse of Brink's Mat strikes again

Death of John 'Goldfinger' Palmer the latest killing related to 1983 heist
Greece debt crisis: 'The ministers talk to us about miracles' – why Greeks are cynical ahead of the bailout referendum

'The ministers talk to us about miracles'

Why Greeks are cynical ahead of the bailout referendum
Call of the wild: How science is learning to decode the way animals communicate

Call of the wild

How science is learning to decode the way animals communicate
Greece debt crisis: What happened to democracy when it’s a case of 'Vote Yes or else'?

'The economic collapse has happened. What is at risk now is democracy...'

If it doesn’t work in Europe, how is it supposed to work in India or the Middle East, asks Robert Fisk
The science of swearing: What lies behind the use of four-letter words?

The science of swearing

What lies behind the use of four-letter words?
The Real Stories of Migrant Britain: Clive fled from Zimbabwe - now it won't have him back

The Real Stories of Migrant Britain

Clive fled from Zimbabwe - now it won’t have him back
Africa on the menu: Three foodie friends want to popularise dishes from the continent

Africa on the menu

Three foodie friends want to popularise dishes from the hot new continent
Donna Karan is stepping down after 30 years - so who will fill the DKNY creator's boots?

Who will fill Donna Karan's boots?

The designer is stepping down as Chief Designer of DKNY after 30 years. Alexander Fury looks back at the career of 'America's Chanel'