Ireland could lose its edge on TB
By Angela Long
The outbreak of tuberculosis (TB) in Cork city has focused attention on the former bogeyman of Irish health, as well as medical practice in the county.
The vaccine BCG has not been administered routinely to babies in Cork, as is the case elsewhere in the country. TB laboratories in the county were closed earlier this year.
The TB outbreak happened in two crèches where an infected adult had been working, and caused 16 confirmed cases of the disease at time of writing.
Most of these 14 - are children, and all are receiving medication, with no fears for long term health.
But TB treatment in Ireland has been in limbo since the closing of Peamount Hospital in 2004, says respiratory physician Prof Luke Clancy.
Prof Clancy was medical director of the hospital, which was the headquarters for TB in Ireland for many years. He says treatment of TB in Ireland has been, and continues to be, very good, but that the Irish standard of excellence is being undermined.
"Our mortality rate is down to 2%, which is very good by international standards. In the UK it is about 10%. But we cannot afford to sit back now."
Professor Luke Clancy
Today there are about 400 cases diagnosed a year, down from 1,000 in the 1980s, and the plague years of the 1940s and 50s, when thousands suffered and died from the disease.
Fictionalised accounts such as in Mary Morrissy’s novel Mother of Pearl paint a poignant picture of the desperation of patients in sanatoriums all over the country.
HSE Southern Region has announced that the universal BCG programme will now be restored in Cork after a break of 35 years.
Dr Clancy says BCG is an important part of an anti-TB strategy, but just one component. "It is only a partial answer," he says. "TB needs a plan, it needs a panoply of things, vaccination, screening, many components in a package."
However not all specialists in the field are convinced of the value of BCG. Dr Charles Bredin, a respiratory consultant, told irishhealth.com he believed BCG should be discontinued as a universal vaccine.
"It is only suitable for targeted populations, such as health care workers, and some deprived populations." He said the vaccine had been discontinued in Northern Ireland some years ago because of doubts as to its benefit. This was why the decision was taken to stop its supply in Cork in 1972, by, he said, an 'enlightened' medical director.
Dr Bredin, who practises at Cork University Hospital, has been warning of the TB threat for some years. In a 2003 article he wrote of 'hidden reservoirs' of TB in deprived inner city areas, including Dublin and Cork.
He wrote of a likely peak in people over 60, who were young children when the mid-century epidemic was in full force. Such people, he said, could fit into a 'classic pattern of reactivation or secondary TB'.
One of the features of the Mantoux skin test, done to check for TB, is that it will give a positive result if the subject has had TB in the past, as well as those currently infected. This is one of the problems with BCG, Dr Bredin says. "A group of children who had the BCG as neo-natals will give a positive reading when they are six, and you don't know if they have TB or this is from the vaccine."
DNA fingerprinting would be a more rigorous and superior way to monitor TB, Dr Bredin says, but it is expensive.
Luke Clancy says the complexity of TB is one of its most worrying aspects. “It is an infection, there can be relapses, it has many forms, such as pulmonary TB and TB meningitis.”
"Young children are very susceptible and the disease can have serious effects, but children don’t spread it. That’s how they knew there must have been an adult with TB in the Cork crèches."
The airborne bacteria can be spread easily, by anyone coughing, spitting, yawning or even singing, he says.
Some fears have been expressed that Ireland is at more risk from TB now that there is significant emigration from eastern Europe and Russia, where some vaccine-resistant forms of the disease have been found.
Prof Clancy says it is not racist to say that new arrivals could be bringing TB. "It is a fact. Countries such Latvia, Lithuania, Estonia all have a high incidence of multi-drug resistance. People have to be screened when they arrive here."
WHAT IS TB?
Tuberculosis, known as TB for short, is an infection caused by a bacterium, Mycobacterium tuberculosis. It is one of the oldest diseases known to man, and was once so common that every adult was thought to have experienced a bout of TB infection during their lives.
TB is contagious, and is caught by inhaling microscopic droplets containing the bacterium, which are produced when an infected person coughs or sneezes. The illness usually affects the lungs, but sometimes can spread to other organs. It gets its name from the tubercles, or hard lumps that form on the lungs to contain the TB bacteria.
TB in the past could be a serious illness. Consumption, as TB used to be called, claimed the lives of up to a quarter of all adults in Britain during the 19th century. TB remains very common in other parts of the world, especially Africa and South-East Asia. Over 80% of India's adult population have had the disease at least once. It is estimated that a third of the world's population could be infected with TB, and over three million may die from it this year.
TB is now much less common in developed countries, such as Ireland. In European countries, the disease is found in deprived city areas, among the homeless, alcoholics, older people, those who are HIV positive and among people who come into close contact with those suffering from TB.
The most common form of TB is pulmonary, but there are also forms which attack the nervous system and the lymphatic system.
BCG is short for Bacille Calmette-Guerin, and was developed in France in the first decades of the 20th century.
The World Health Organisation says:
- Someone in the world is newly infected with TB bacilli every second.
- Overall, one-third of the world's population is currently infected with the TB bacillus.
- 5-10% of people who are infected with TB bacilli (but who are not infected with HIV) become sick or infectious at some time during their life. People with HIV and TB infection are much more likely to develop TB.
- An estimated 1.6 million people worldwide died from TB in 2005. However the incidence around the world is falling.
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