As World Tuberculosis Day approaches on 24 March, Dr Helen Donoghue (UCL Clinical Microbiology) ends this term’s series of Lunch Hour Lectures by looking back at 9,000 year old tuberculosis DNA.

MTB via Flickr

What is tuberculosis 

Tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis (MTB) that spread via aerosol and primarily affects the lungs.

Although there are current health scares about antibiotic-resistant strains of TB, due to modern sanitation, vaccination programmes and antibiotics there have not been any major TB epidemics in the UK in the 21^st century. However, it is currently estimated that one third of the world’s population is infected with various strains of MTB. These infections often pass under the radar because the majority of them are latent, meaning that the infected person does not have any symptoms of the disease.

TB is one of the world’s oldest diseases, in part due to this high level of latency. There are multiple strains of MTB, all associated with differing areas of the globe. What is striking about these strains is that people with TB generally carry the strain of MTB associated with their ethnic origin, despite their current location.

For Dr Donoghue, this is evidence that MTB has evolved with humans. She argued that in the Neolithic and Palaeolithic periods, when humans lived in small populations, pathogens that were highly infectious and killed their hosts quickly failed to survive as they would simply wipe out tribes. In contrast, MTB’s combination of high latency rates and virulence means that carriers transmit the disease before dying.

What’s more, evolving with humans has meant that there are numerous strains of extinct MTB, as well as extant MTB. The research conducted by Dr Donoghue and her team means that new methods are being perfected to analyse these extinct, ancient strains. (more…)

TB research has changed over the past 10 years. Growing collaborations have led to huge advancements in testing and treatment for a disease that kills every 20 seconds.

But this progress is threatened by reduced financing of health programmes by the Global Fund, which accounts for two-thirds of global TB funding, leaving money only for ‘essentials’.

“Lives are on the line,” said Simon Logan, a policy advisor from the All Party Parliamentary Group on Global Tuberculosis, who is now urging the public to engage in dialogue about the potential impact that Global Fund restrictions will have on the disease.

The challenge of TB
World TB Day, held on 24 March, marks 130 years since Robert Koch discovered the bacteria responsible for the disease. The ‘UCL ‘Local and global’ TB conference last week coincided with a TB supplement in the Journal of Infectious Diseases – this year, the focus is paediatric TB. There are major challenges to tackling the disease and many are particular to children. These include under-reporting of cases, diagnostic difficulties and the need for better quality drugs.

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On 24 March, UCL’s Institute for Global Health marked World TB day with a call to arms to tackle TB globally, bringing together experts to highlight UCL’s contribution to addressing this problem which, according to UCL’s Professor Ali Zumla recent Lancet publication, results in an estimated 1.7 million deaths each year and more than 9 million new cases each year.

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