Three weeks ago a young man came to see us with what he thought was a trivial complaint. He hadn't lost his cough after a bad dose of the flu in January, but he thought that was just normal. Plenty of his friends had the same trouble, and the advice he had seen about it on TV and in the papers was that it would take time to get better.

So far, so good. He had done the right thing. But things didn't get better. He started to sweat really heavily at night. His twice-weekly five-a-side football games were making him much more breathless than before. And his mum was getting worried about how pale and how thin he was. She checked his weight - and he found he had lost half a stone. She chased him to the surgery - and we were glad that she did.

Because we noticed small flecks of blood in his spit. And we heard sounds in his chest that shouldn't have been there. His X-ray and sputum tests confirmed he had tuberculosis.

The diagnosis, to be honest, surprised us. If this case history had happened 50 years ago, TB would have been top of the diagnostic list, because every doctor saw dozens of cases each year, and was familiar with the symptoms. But in 1999, when the disease is supposed to have been beaten, and most practices have not seen a case for years, TB hardly crosses our minds as a possibility. That must change, because it looks as if we are going to see more cases.

Happily, our young patient's story is ending well. His TB germ is susceptible to the modern anti-tuberculous drugs, and he is already feeling much better. He will be completely cured, though he will have to be under his doctor's care for a year or more.

Making the diagnosis was only the beginning of the problem. How had he caught the disease? Tuberculosis is spread by close contact between people who spend a lot of time together. As a rule of thumb that means everyone sharing the same household, or anyone that spends four or more hours a day in a relatively confined space, such as a small office, with the patient. So far we have drawn a blank with our patient's contacts, but we are still looking.

Many of those who get tuberculosis are older people who had the disease when young, and whose poor state of health allows infections that have been dormant for years to arise again. But it hits people of any age, including schoolchildren and students. And it isn't always a chest illness. It can affect the lymph glands inside the abdomen, giving repeated attacks of pain and diarrhoea that are often very difficult to diagnose unless the suspicion is there. It can also affect the kidneys, so that the first sign is a form of kidney failure. But most of these TB sufferers share that feeling of being tired, listlessness, and the loss of weight with those whose problem is in the chest.

What really matters about TB is that the infection is treated properly. That means giving the cocktail of different drugs that together will kill the germ so that it can't become resistant to them.

However, that may soon change. The experts are worried about steeply rising numbers of cases of drug-resistant TB in Eastern Europe, Africa and Asia, where anti-TB treatments have not been properly supervised, or where people have "economised" by giving only one drug at a time. Communities where many people regularly visit Asia must be particularly vigilant against a chesty illness that comes on shortly after returning.

The long-term problem, however, can only be solved by supporting efforts to get economic and medical aid into the countries where it is rife - before it spreads to us. Tuberculosis is still the biggest killer of all the infectious diseases, killing more people world-wide than malaria and AIDS added together. It is easy to cure. All that's needed is the will and money to tackle it.

Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.