Tuberculosis is on the rise again. Poverty, overcrowding and the dismantling of TB services are to blame. Liz Hunt reports
In the rundown pubs and clubs of inner-city Liverpool lurks an unwelcome reminder of another time. It attacks the old and the young, and it thrives on poverty, overcrowding and ill health.

Tuberculosis is making its presence felt in this community living on the fringe, made up of men and women, predominantly white, many of whom have never worked and are unlikely ever to do so, and who move in and out of each other's lives with seemingly careless frequency.

At a city hospital one morning last week, Dr Peter Davies, a consultant chest physician, was pondering the problem of "Mac", a man in his sixties with an old face and a lithe body. Mac says he was a trapeze artist. He also says he has 14 children by eight women, which may be true; his nurse says: "He's a real charmer."

Mac has had infectious TB - with a racking cough and dramatic weight loss - for months. Yet it was detected only by chance. A TB nurse heard about his symptoms while visiting a former patient, a woman who now lives with one of Mac's sons. Eighteen months ago her TB was picked up when her then partner was diagnosed as having the disease. Both were treated successfully. "It is possible that she has relapsed but ..." Dr Davies shrugs. "There is a whole subculture in Liverpool and there is a lot of TB in it. He's just one example."

Liverpool is not the only city becoming reacquainted with TB. After decades of decline, the disease is resurgent, in developed and developing countries. Experts will meet at a special conference in Washington DC next week, organised by the Lancet, to discuss ways of making governments and the public "TB conscious". One of their aims is to reverse the dismantling of TB services in some Western countries that began in the Eighties with the non-reappointment of chest specialists and TB nurses as they retired, and the abandonment of TB immunisation in some schools.

Judging by current trends, TB will increase by 100 per cent in Africa and 50 per cent in South-east Asia over the next 10 years, according to World Health Organisation figures. HIV is a significant factor in this explosion; TB is a leading cause of death in Aids patients.

But it's not just HIV. In 20 of 27 countries formerly part of the Soviet Union, TB deaths are rising, too, as public health infrastructures break down. Denmark, France, Italy, the Netherlands, Sweden and the UK all are reporting rises, due in part to immigration from high-prevalence countries, and increasing poverty and homelessness.

In England and Wales, the rate of decline in TB notifications began to slow in 1985, reaching a low of 5,085 cases in 1987. Since then the trend has reversed, with 5,700 cases reported last year.

With around 100 new cases a year in Liverpool, checking the disease's spread is demanding of time and resources. TB is passed from one person to another in airborne droplets expelled in coughing or sneezing. Left untreated, someone with active TB can infect 10 to 15 people in a year. An outbreak at a social club in north Liverpool three years ago resulted in seven adults and one child becoming infected. The outbreak was detected by chance when two members of the same club turned up as out-patients on the same day, and the link was made. Four hundred people had to be called in for tests. In a parallel incident in the US, one man with a highly contagious form of pulmonary TB infected 41 others in a Minneapolis bar - and 14 became seriously ill.

In Mac's case, his contacts were spread around seven pubs, all within "staggering distance", says Ceridwen Williams, one of two TB nurses serving the city who co-ordinate the detective work. People who may have been exposed to infection had to be traced, given a Heaf skin test, which indicates exposure to the TB bacillus, and possibly a chest X-ray.

Mac's case also highlights how hard it is to treat the disease. He is no longer infectious but will need a six-month course of three antibiotics to rid his body of the bacterium. Mrs Williams can fit in a home visit only once a fortnight. She usually relies on a family member or neighbour who will watch a patient take their drugs every day.

In Mac's case that is not possible. He drinks eight to 18 pints a night and lives alone. If he is discharged now, what are the chances of him continuing to take the drugs? Mac is realistic. The drugs can react with alcohol and cause liver damage. Already under pressure to quit cigarettes, he knows he can't give up drinking, too. "I might as well pack up life itself," he says. "We'll have to keep him in until we've worked out what to do," says Dr Davies.

If drug treatment is incomplete, the consequences can be disastrous. The bacilli can survive and multiply in the lungs. They may then develop into highly dangerous, drug-resistant strains. The WHO says death rates for some strains of multi-drug resistant (MDR) tuberculosis are higher than for the deadly Ebola virus, which has emerged in Africa, as well as some cancers.

There have been numerous outbreaks of MDR tuberculosis in US cities but just a handful of cases in Britain - 42 last year. But the risk of an outbreak is growing. Last month, the Independent reported what is believed to be the first UK outbreak of MDR tuberculosis at the Chelsea and Westminster Hospital, London. An Aids patient may have infected four others and more than 50 people are being traced by 12 health authorities across the country.

One way that MDR tuberculosis may arrive in the country is through immigration. At a TB contact clinic at Sefton General Hospital the day after seeing Mac, Dr Davies saw a middle-aged man who had recently arrived from Bangladesh to join his family. He complained of a cough and his X-ray showed the characteristic hazy shadows over the upper lobes of the lungs. TB was diagnosed in India and he was prescribed drugs for two months. Dr Davies decided to admit him. "He's had two months' alleged treatment. We need to get him in to see if it is TB, and we've got to get specimens to see if he has drug-resistant strains." Mrs Williams has the task of screening the family of 10.

Three regions worst affected by TB are the South-east, West Midlands, and Yorkshire and Humberside. Their cities have large concentrations of ethnic minority groups. Yet immigration alone is unlikely to provide the explanation, nor does HIV appear to play an appreciable part in the increase. In fact, the Public Health Laboratory Service reports a particular rise in cases among young and middle-aged women living in cities. Dr Davies says social deprivation is the single most important factor.

A truer picture will emerge when results of the 1993 National Survey of Notifications of Tuberculosis in England and Wales are published later this year. The last survey was done in 1988, just as the number of cases was starting to rise. Until the new data is available, says Dr Davies, we remain in relative ignorance as to who are most at risk of the disease. And many of those detected will, like Mac, be picked up by chance. Names have been changed.