New strain of cholera puts world at risk

SCIENTISTS believe that the world is facing a new cholera epidemic, possibly the biggest this century.

A strain resistant to all known vaccines has appeared in Asia and has already claimed thousands of lives. In the next three years it could spread into Africa, the Middle East and the Mediterranean.

In 1992 more than 500,000 cases of cholera were reported worldwide. But this year the figure could double, and within two years the number of cholera fatalities may increase tenfold.

Although first detected in Madras, southern India, last November, the bacterium is known in laboratories around the world as Bengal cholera, because its impact there has been most devastating. The six other cholera epidemics this century all originated in the Ganges delta. Scientists claim this new strain could be the most virulent yet.

It is still a mystery how and where Vibrio cholerae 0139 came into being. Dr Balkrish Nair, a Calcutta toxicologist and head of research at the National Institute of Cholera and Enteric Disease, discovered the bacterium. 'It's extremely toxic, hardier than all other cholera bacteria and it spreads very rapidly,' he said. 'The chances of those characteristics coming together in one kind of cholera organism were probably a trillion to one, but it's happened.'

Three weeks ago the World Health Organisation warned South Asian countries to be on the alert for the bacteria, but it has already appeared in Nepal and Bangladesh, claiming thousands of lives.

Malaysia and Japan have had isolated cases, and Japanese health authorities found cholera inside a seafood consignment from Bangladesh. One international medical specialist in Delhi said: 'We're worried that it could become a new, worldwide epidemic.'

Cholera is caught from contaminated food and water. The bacteria lives in water, but can only reproduce itself inside human intestines. It has festered, multiplying and mutating, in the swamps of the Ganges river delta since the 12th century and is now a significant killer in developing countries that have poor sanitation.

Cholera is deadly because its onset is relatively mild. Often mistaken for food poisoning, it causes severe diarrhoea and death from dehydration within nine hours, six for children.

Calcutta's teeming slums, where open sewers and stagnant ponds are used for bathing and washing by millions of poor, have been hardest hit by the cholera outbreak. Over 22,000 cases were reported last month in one city hospital, the Infectious Disease Hospital. It reached a peak of 500 cases a day, when cholera victims arrived on rickshaws with friends running alongside holding intra-venous drips.

'There was so little space we were putting four patients to a bed,' said Dr B K Das, hospital superintendent.

Dr Nair said Bengal cholera could spread out from India along traditional epidemic routes: scything across Asia and into Africa, and eventually moving into the Middle East and the Mediterranean countries. 'It will take another two to three years to reach its peak, but it will travel far,' said Dr Nair.

In an earlier epidemic, in 1991, cholera spread across South America from the Pacific coast of Peru. Peru alone had registered 231,600 cases, nearly 2,300 of them fatal.

India's time of cholera, page 12