Scientists predict that up to a half a billion people will be infected with TB in the next 50 years if present rates continue.
And they say that growing numbers are developing multi-drug resistant forms which can cost $250,000 (pounds 170,000) per patient to treat, compared with less than $100 for non-resistant forms, and are often incurable.
"Not only has TB returned, it has upstaged its own horrible legacy," said Dr Hiroshi Nakajima, director-general of the WHO.
Paul Nunn, chief of research for the WHO's global TB programme, said the threat was far worse than that posed by the possible link between mad cow disease and Creutzfeldt-Jakob disease. While the UK population should be legitimately concerned about CJD, he said, the scare should be put in perspective.
"The Government's report states there are 10 cases of CJD which may be linked to mad cow disease. There are 3 million deaths a year from TB. That is a rather larger number."
Increased travel to and from countries where TB is endemic and control is poor; migration; political upheavals, with the accompanying collapse of public health infrastructure; and the growth of homelessness and poverty, are responsible for the re-emergence of the disease in the developed world.
Outbreaks of multi-drug- resistant TB have now been reported recently in London, Milan, New York City, Chicago, Atlanta, Paris, Estonia, and cities in India, Thailand, South Africa, and Pakistan.
Mass screening - chest X-rays were a useful public health weapon against TB until the 1950s - is once again being made available by charities, such as Crisis, to high-risk groups such as the homeless.
Speaking at a press conference in London yesterday, Dr Arata Kochi, director of the WHO's global programme, said that many politicians were "still behaving as if TB did not exist" despite the alarming figures.
"The bad news is the TB epidemic is moving faster than we are. The frightening extent of the spread of TB has yet to be understood by many leaders. Governments in wealthy and developing countries alike are still not responding to the warnings that their people are at serious risk . . . Other diseases - such as flesh-eating bacteria, plague, and the Ebola virus - have captivated the public's attention, and are higher on the public policy agenda than TB."
Dr John Moore-Gillion, chairman of the British Lung Foundation, said that TB in London had risen by 50 per cent since 1987, and there were now "an extra 8,000 unexpected new cases" in Britain. "Cases of multi- drug-resistant TB occur in scores, not thousands or hundreds of thousands. Will we see more? If we let our guard down, then yes we will," he said.
Better surveillance, improved diagnostic testing and more powerful drugs, were urgently needed, Dr Moore-Gillon said. "We need greater public, professional, and political awareness. Predictions made in the 1950s that TB would be eradicated from developed countries and there would be great progress in the Third World in controlling it, were horribly and devastatingly wrong."Reuse content