FEARS HAVE been raised about the risks involved in travelling to Asia because of a new and virulent strain of cholera sweeping through eastern India and Bangladesh. Vibrio cholerae 0139 has affected 60,000 people and killed nearly 1,000. Experts fear it could become a pandemic and spread to other parts of the subcontinent and beyond.

'Because it's a new strain there's a lack of immunity,' says Dr Peter Barrett, consultant to the Medical Advisory Service for Travellers Abroad (Masta). The cholera vaccine is less than 50 per cent effective against normal cholera, and gives no protection at all against the new variant.

'Few Western visitors come into contact with the insanitary slums where cholera thrives,' says Dr Barrett, 'but it's important to be aware of

the dangers.' The greatest risk is from contaminated food and water. Ideally you should sterilise water by boiling it. If this is impracticable use an iodine-resin purifier, or drink bottled water - but check that the seal is intact. Avoid ice.

Dr Barrett offers succinct advice about food: 'If you're not sure about it, don't eat it.' Be especially wary of shellfish and salads.

As we reported last month, Masta has launched a telephone service: dial 0891 224 100, detail the countries to be visited and the dates of arrival in each, and it will dispatch a personalised health brief by the next first-class post. Each health brief gives advice on immunisations and malaria tablets; prevalent diseases and the latest health situation in the countries to be visited.

The cost of this service is the cost of the call - 36p a minute cheap rate, 48p a minute at other times - making the average about pounds 2 (not pounds 5 by post and pounds 7 by fax, as previously indicated).