Quiet return of the 'white plague'
IN the biggest outbreak of tuberculosis at a British school in recent years, 62 cases have been confirmed at Crown Hills community college in Leicester.
This follows other recent outbreaks, including one at a nursery school in Wandsworth, south London, where three cases of TB have been confirmed and five others are being investigated. The latest school to be affected is Ducie high school in Manchester where a teacher has been diagnosed with what used to be known as the "white plague".
The publicity surrounding these flare-ups has raised fears of a resurgence of a disease once thought to have been wiped out by mass immunisation and modern drug treatment. But TB never did go away. Although the disease declined steadily in Britain for most of the 20th century, it has been on the rise again since the late 1980s, with almost 7,000 cases reported last year.
Growing international mobility is a major factor in this increase. Around the world, there are around eight million new cases of TB every year, with southern Africa and parts of Asia especially hard hit by the disease.
According to a 1998 survey by the Public Health Laboratory Service, 56 per cent of TB cases in Britain occur in patients born abroad and, because the disease develops slowly, they are not necessarily recent arrivals. But the backgrounds of pupils and staff at Crown Hills do not seem to explain what happened there.
Dr Louse Coole, senior registrar in public health with the Leicestershire Health Authority, points out that although a high proportion of the school's pupils were born or have visited parts of the world where TB is widespread, that is equally true of many schools in Leicester and elsewhere that have not been affected by the disease.
"What happened in the school is unusual and probably pertains to something unusual about the strain of TB involved or to something unusual about the opportunities for transmission to occur," she says. Most of the children involved in the Leicester outbreak had been vaccinated against TB before a shortage of the BCG vaccine led to the suspension of the national immunisation programme in September 1999. This vaccine does not, in any case, give complete protection against the disease. So the suspension of the vaccination programme has been ruled out as a possible explanation for the outbreak at Crown Hills.
Leicestershire Health Authority screened all 1,250 pupils and 170 staff at the school for TB last month after confirming three cases in the same Year 9 tutor group. Fifty-four pupils, two members of staff and six family members were found to be suffering from the disease.
In addition, 99 pupils with normal chest x-rays had a positive reaction to a skin test used to detect exposure to the TB germ. This means that although they do not have the disease, they may go on to develop it, and as a prcaution they are being treated with antibiotics. The health authority has also identified a case in each of five other schools in Leicestershire. These cases do not appear to be connected either to each other or to those at Crown Hills. However, the health authority is waiting for the results of genetic fingerprinting tests to confirm this. Meanwhile, the message from the health professionals is that there is no need to panic.
"The important thing to remember is that this is a very treatable disease, which progresses very slowly and is very difficult to catch without close and sustained contact," says Dr Coole. Schools, she adds, should look out for children with long-term unexplained illness and liaise with their health authorities where appropriate.
They also need to recognise that TB has not been consigned to the history books. But beyond that there does not seem much they can do to prevent pupils or staff catching the disease.
"For most schools around the country, the occurrence of tuberculosis is very, very uncommon and a tuberculosis-awareness programme would be inappropriate for that level of risk," says Dr John Watson, consultant epidemiologist at the Public Health Laboratory Service.
"But certainly, in parts of the country where tuberculosis rates are high, such as some of the inner-city areas, particularly in London, it would be appropriate for school staff to be aware that the likelihood of tuberculosis occurring is rather greater - and I think to a very large extent they are."
DETECTING EARLY SIGNS OF TUBERCULOSIS
Tuberculosis usually affects the lungs but can strike other parts of the body, including the lymph nodes, bones and, more rarely, the brain. The TB germ, Mycobacterium tuberculosis, is spread in the air when a person with TB of the lungs coughs, sneezes or spits.
There is a difference between tuberculosis disease and infection. Many people who breathe in TB bacteria and become infected never develop the disease. They have no symptoms and cannot spread TB to others, although they can develop the disease later in life. Any of the following symptoms may indicate the presence of TB:
* a cough lasting three weeks or more * phlegm containing blood * loss of appetite * weight loss * fever and night sweats * tiredness People at most risk of developing the disease include children, the elderly and those taking steroids or other drugs affecting the body's immune system. People who are HIV positive or live in overcrowded housing also have a greater chance of falling ill if they come into contact with the bacterium. TB can now almost always be fully treated with a course of antibiotics. Early diagnosis and treatment are the best ways of stopping the disease.
Source: Public Health Laboratory Service. Further information on TB is available from the website: www.phls.co.uk
Graph showing fall and rise in the number of cases of TB in England and Wales NOT available on this database.