An article in today's Lancet entitled "The white plague returns to London - with a vengeance" should strike terror in the minds of our legislators. In the nineteenth century a quarter of all deaths in Europe were due to tuberculosis. Even in my youth the initials TB were only whispered in polite company. In past 60 years better housing, nutrition, and economic status, effective anti-tuberculosis drugs and BCG vaccination have reduced the incidence so that what John Bunyan called the 'Captain of these men of death' has been demoted to a mere corporal. That is true for the whole of Western Europe, but not for London, and not for the rest of the world, where 1.7 million people die annually from TB.
The problem is that London has become home to the rest of the world. The number of cases in London has increased by nearly 50% since 1999, from 2309 in 1999 to 3450 in 2009, accounting for almost 40% of all tuberculosis cases in the UK and this is certainly an underestimate. A further worry is that many of the new cases are multi-drug resistant.
The increase in the number of cases in the UK has largely been in people not born here, though 85% of them have lived here for more than two years. In 2009, there were 28% black African28%, 27% Indian, and only 10% white sufferers. Tuberculosis was commonest in London boroughs that are relatively deprived with poor housing, inadequate ventilation, and overcrowding.
London has a problem with housing. It has always been an entry point for immigrants. When I applied for the London Hospital Medical school in 1961 the Mile End Road was occupied by shops with names like Isaacs, Abrahams and Jacobs, now all the signs are Bangladeshi. The Jews now live in Enfield and Barnet, the Hindus have moved to Southall, the Afro-Caribbeans to Camberwell and Peckham - once a working-class white area. Islington and Hackney have become gentrified and the same is happening to many unfashionable areas that were once shabby Victorian terraces. Houses in Camden - once a home for the laboring Irish - now sell for over a million pounds.
Immigrants live in central London because there are many low-paid jobs there - office cleaning, care home skivvying, minicab driving, short-order cooking, clothing sweat-shop sewing, and male and female prostitution. There is even slavery in the employ of rich potentates from the Near East. Although it is poorly paid, it seems like a fortune to what they could make in Bangladesh or even Bulgaria. They feel that they ought to send money home and they do - as much as they can. What they don't realize is how much it costs to live in London. They get subsidized housing, but their landlords are unscrupulous. The greatest rents can be achieved in houses of multiple occupancy. It used to be a joke among medical students that when they had a room in the hospital so they could be on-call, they were so busy that they let their room to a family of 17 Pakistanis. That is an exaggeration, of course, but there is a nub of truth there in that immigrants put up with a good deal of overcrowding. Hot-bedding is common enough to be a cause of the spread of infectious disease.
Why is it that immigrants who have been here for greater than two years have the highest incidence of TB? Most immigrants from sub-Saharan Africa and South Asia will have been exposed to a primary infection with TB, but those that don't die and are strong enough to emigrate will have a degree of immunity. The most obvious cause for a fall in their immunity in London is infection with HIV that insidiously gets worse with time. The commonest cause of AIDS in the UK is no longer gay sex, but women having unprotected sex with a black African. However, HIV does not account for the whole of the problem.
Containment of the TB bacillus is the responsibility of the moncyte/macrophage system. It derives from the same progenitor as granulocytes. What directs the maturation down monocyte lines is vitamin D3, but dark skinned immigrants in London don't get enough vitamin D3 made from sunlight. Perhaps this is part of the problem, which would be easily remedied by vitamin D3 supplements in food?