A cheap drink of salt, sugar and water transformed the fight against cholera.
Cholera and other diarrhoeal diseases kill largely by draining the body of water and salt. For decades the answer was an intravenous drip. Then researchers found that the gut keeps absorbing salt and water even during severe diarrhoea, as long as sugar comes along too. The treatment could simply be drunk.
The trick lies in how the gut absorbs sodium. Cells lining the intestine carry sodium inside by pairing it with glucose through a transport protein called SGLT1, and water follows. Without glucose, much of that sodium is not taken up. In the early 1960s Robert K. Crane described this sodium–glucose co-transport, and because the intestinal lining appears undamaged in cholera, researchers reasoned the mechanism might keep working during the illness. Earlier efforts had faltered, including one solution that was too concentrated and aimed at stopping the diarrhoea rather than replacing lost fluid.
In 1967 and 1968, Norbert Hirschhorn and Nathaniel Pierce showed that people with severe cholera can absorb enough glucose, salt and water to stay hydrated. In 1968 David Nalin and Richard Cash, working with Rafiqul Islam and Majid Molla, reported that giving adults with cholera an oral solution matched to their losses cut the need for intravenous fluid by 80 per cent.
The real test came in 1971. The Bangladesh Liberation War drove millions into refugee camps, cholera broke out, and intravenous fluid ran out. Dilip Mahalanabis, a physician working in Calcutta, had an oral solution prepared and handed to families and carers to give. More than 3,000 cholera patients were treated this way, and deaths among them were reported at 3.6 per cent, against 30 per cent among those given intravenous fluid. In 1980 the World Health Organization launched a global programme, and in Bangladesh the organisation BRAC sent teams from village to village teaching mothers to make a solution from household ingredients. National surveys now find almost 90 per cent of Bangladeshi children with severe diarrhoea receive oral rehydration fluids.
Estimates suggest oral rehydration therapy can lower the risk of death from diarrhoea by up to 93 per cent, and it is on the WHO's list of essential medicines. It does not shorten the illness; it keeps people alive while the illness runs its course, and severe dehydration still needs urgent intravenous treatment. Yet as of 2015 only about four in ten children with diarrhoea worldwide received it, a reminder that even the simplest tools have to reach people to work.
Source: Wikipedia — Oral rehydration therapy · Text summarised from Wikipedia (CC BY-SA 4.0)
