Scourge of Mankind for at least 5,000 years

Signs of the disease have been found in an Egyptian mummy dating back to 3,400BC.

It is caused by bacteria and thrives in places where people are poor, ill-nourished and crowded together. Although a cure was found more than half a century ago, it remains the third-biggest killer in the world.

The TB bacillus, mycobacterium tuberculosis, most commonly affects the lungs and lymph glands, but only the respiratory form is contagious.

The disease is spread through the air through coughs or sneezes. Those in close contact with a sufferer are most at risk, but the bacteria can remain active for several hours in confined warm places.

In most people, a healthy immune system will fight the infection by walling off the bacteria into tiny capsules called tubercules. About five per cent of people with latent infection go on to have active TB within two years. Another five per cent develop the disease at some point within their lifetime.

Symptoms include coughing, fatigue, night sweats, unexplained weight loss and fever. If left untreated, cavities may form in the lungs. These can cause bleeding or can become infected with other bacteria, leading to abscesses. Other complications can include holes forming between nearby airways in the lungs and blocked airways within the lungs.

TB has a romantic image, formed through its associations with 19th-century poets, artists, writers and musicians.

Among those to die of the disease - which was often called phthisis or consumption - were Chekov, Chopin, Kafka, Keats, Robert Louis Stevenson, the Bronts and D H Lawrence.

The first sanatorium was built in the 1850s, where patients could rest, get plenty of fresh air and good food. Some were sent to Bournemouth and other seaside resorts, while others went abroad for the change of climate or clean mountain air.

Sanatoria remained in widespread use throughout Europe and the United States until after World War Two, when a new antibiotic called streptomycin provided the first cure for TB and paved the way for other drug treatments.

Before antibiotics, the death rate for TB was around 50 per cent, but after the war, the rate was brought down to around two per cent in western industrialised countries.

But the disease remains a huge problem in the poorer countries of Africa, Asia and Latin America. The World Health Organisation estimates that of the eight million people who become infected each year, 95 per cent live in developing countries. Two to three million die annually.

Those most at risk of developing the active disease are people with weakened immune systems, including those with HIV, and people who do not have access to proper health care, including the homeless.

Health officials are worried about the increasing incidence of TB in western Europe, particularly as antibiotic-resistant strains have been emerging.

In London, the rate of 32 cases per 100,000 population is among the highest in the European Union, perhaps because the capital acts as a honeypot for immigrants.

Among people from the Indian sub-continent, the rate of TB is nearly 40 per cent higher than it is among the white population, while the incidence among asylum seekers is 22 per cent higher than the national average.

Here in the south-west region, there were 229 cases of TB in the year 2000, a 15.1 per cent rise since 1999. In this country, schoolchildren are usually offered a BCG inoculation in their teens to increase their immunity to TB.