ALL insomniacs, particularly those who are also depressives by nature, drop off to sleep just as the dawn chorus begins and the BBC World Service makes way for Radio 4. This year the dawn chorus seems to have started earlier than usual. It may be because of better street lighting or a warmer spring, but it confirms that when the Romans celebrated Lupercalia to mark the start of the mating season for birds, they chose the correct time. For the Lupercalia was transformed under later Christian influence into St Valentine’s Day and a celebration of various saintly acts rather than the sex life of the blackbird.

It is, therefore, appropriate that La Bohème is being staged by Francesca Zambello at the Royal Albert Hall. The opera should be interesting to the least musical of doctors as it captures so many of the features of tuberculosis in the decline of Mimi (sung by the sopranos Mary Plazas and Abbie Furmansky).

Mimi lived a full bohemian life while she continued to scatter the bacillus Mycobacterium tuberculosis as liberally as she distributed her sexual favours among her artistic friends and her rich benefactor. Although she was milking her charms for all they were worth, she still lived — when not with her ageing, rich lover — in an overcrowded, squalid, cold and damp garret.

The same environment has favoured the spread and growth of TB down the ages. Mimi’s breathlessness became more restricting as she continued to struggle up the stairs, and her coughing fits began to worry Rodolfo, one of her student lovers, whose desire for her was tempered by his fear of catching the bacillus.

La Bohème is an appropriate opera for the Valentine season, as it embodies a complex love story and torrid emotions while highlighting the strange Victorian belief that tuberculosis acted as an aphrodisiac.

In Rodolfo’s emotions there was conflict between his fear of TB and the appeal of the beautiful but wasting Mimi. The Pre-Raphaelites, and even the solid Victorian artist Sir Luke Fildes could never resist using a dying, beautiful waif as their models. The romantic myth that there is something ethereal and glorious about death from TB was not supported by reality. John Keats’s death in Rome, held up for centuries as a suitable end for a poet, was particularly unglamorous and much closer to the truth.

In the early 19th century tuberculosis brought premature death to one in four people and continued to be a serious public health problem until after the Second World War. It has always flourished in overcrowded conditions, particularly when the squalor that these produced was compounded by a poor diet, too much alcohol and all the other factors associated with social deprivation.

Fifty-five years ago a combination of improved living conditions, the introduction of antibiotics and the development of BCG immunisation made it seem that TB was being consigned to the history books and the memories of ageing doctors.

But not so — over the past few years there has been a resurgence of TB in this country, as well as in the rest of the world. The incidence of TB in the UK tripled between the late 1980s and early 1990s and has continued to rise. In the year 2000 there was a 10 per cent rise in one 12-month period in the number of cases recorded in London. Since 2000, the figures have continued to increase but the rise, for the time being, shows signs of levelling off.

Many of those with TB were born overseas. It affects 100 in 100,000 of those who have come to Britain from the Indian subcontinent, and 200 per 100,000 of those who originated in Africa.

TB is a bacterial infection usually spread by droplets, and hence usually attacks the lungs, but it can involve other parts of the body. TB meningitis was relatively common in the past, as was TB of the lymph glands, bones and kidneys. As with Mimi, pulmonary TB in patients shows, as it did then, with coughing and breathlessness, together with loss of weight, exceptionally severe fatigue and nights that are disturbed by heavy night sweats, as well as by coughing. The cough is often productive and the sputum may be bloodstained.

There is good news. This week Medical News Today reports that a new vaccine is about to start trials in the United States. It will be the first new vaccine for more than 60 years. The laboratory-made vaccine combines two TB proteins, which will stimulate strongly the human immune response. BCG has its values but its effect wears off, and it is least effective against pulmonary TB.

TB is rapidly curable so long as patients take the full course of an appropriately prescribed and changing mixture of antibiotics. Adherence to the regimen is essential; without it resistant strains will emerge.

La Bohème opens on February 26 at the Royal Albert Hall, London SW7 (020-7589 8212).