Shot or Mugged? Wrong, the biggest danger is from TB

It was supposed to be a routine check-up at which the worst possibility was to be asked to cough by a doctor with chilly hands. So it was surprising to hear the note of urgency in the nurse's voice. "Could Mr Reeves come this way at once?"

I had been looking forward to reading my Glendale News-Press (headline: "Glendale Agog Over Marcia Clark's New Hair-do"). The room was full of bandaged, bored people. Why pick on me?

"Let's have a look at your forearm," she said. She peered at the same red blot that I had casually shown the receptionist when I arrived. "Yup," she said, "She was right. TB positive."

When I moved to Los Angeles more than three years ago, I brought certain expectations, mostly the consequence of watching bad television. I knew people could be shot at random, especially if they strayed into gang- occupied areas; I should not have been surprised to be mugged, or burgled.

What I had not anticipated was encountering a disease which (in my ill-informed view) was largely the preserve of 19th-century Romantic poets and, in the US at least, 20th-century down-and-outs. It was my fault: for too long I had tempted fate by scoffing at Californian friends for worrying obsessively about their iron intake, their personal training regimes ...

The nurse was quick to put matters in proportion. "You don't actually have TB," she said, "It's an airborne disease, and this skin test just means you have been exposed to it, that it's somewhere in your system, and that there's an outside chance you could develop it."

There was a choice: it could be treated by a drug, but this could damage the liver and had even, in rare cases, led to death. More to the point, the course took at least six months, during which all alcohol was banned. Or one could do nothing, and hope to be among the 90-95 per cent who test "TB positive" but never get the disease. After a chest x-ray, which found nothing, the latter course was adopted.

No one knows precisely how many in the US are "TB positive". Not everyone is screened and the test is not always accurate (especially among those who have had the BCG vaccination in Britain). But a tentative estimate is about 10 per cent - a figure that rises to 50 per cent among the homeless, the incarcerated, and some immigrant groups. TB is everywhere.

Until the past two years, it has been spreading like wildfire, particularly among the homeless and impoverished in metropolitan areas such as Los Angeles and New York. Latest figures (for 1993) from the Centre for Disease Control and Prevention show there were 25,287 full-blown TB cases in America - a figure that has risen by 20 per cent in the past decade, after a long period of steady decline.

Medical experts cite many reasons - the emergence of the HIV virus, global air travel, the growth of a deprived underclass, drug abuse, and immigration.

But health authorities have a still greater reason for concern. While most TB cases can usually be cured (except among Aids sufferers), these do not include emerging drug resistant varieties.

Some of these can conquer as many as 11 types of drugs, either killing their victims or dooming them to life in isolation. So far only 1.6 per cent of California cases have been classified multi-drug resistant.

Just now Americans are particularly attuned to the risk of large-scale epidemics. Two years ago, an intestinal parasite, cryptosporidium, infected 403,000 people in Milwaukee, the largest attack of waterborne illness in US history. Americans have watched with horror as cholera has re-established itself among their Hispanic neighbours.

The topic, the subject of a forthcoming White House conference, is high on the national agenda - The Hot Zone, Richard Preston's book about the spread of a deadly African virus is a best-seller. Even Hollywood has taken it up, with Dustin Hoffman's The Outbreak.

But it is serious. At a panel on infectious diseases in Washington last month, the Nobel-prize winning biologist Joshua Lederberg asked: "Will we get them, before the bugs get us?" He was in deadly earnest.