My name is Chris Dye and I'm the Director of Health Information for AIDS, TB,
Malaria, and other tropical diseases at the World Health Organization in Geneva.
Tuberculosis is still responsible for
more deaths each year than any other pathogen except HIV,
and drug-resistance is one of the most pressing problems in TB control today.
In 2008, WHO recorded more cases of drug-resistant TB than ever before.
Multidrug-resistant TB, which is resistant to the two main first line drugs,
has been found in every country that's looked for it,
and by March 2009, extensively drug-resistant TB,
which is resistant to both first and second line drugs,
have been found in more than fifty countries around the world.
Scientists are now talking more frequently about the end of the antibiotic era.
So are we on the point of losing control of TB all together,
hope it would returned in the 21st century to the days
when TB killed half of all patients that contracted the disease?
I'm going to divide this discussion of antibiotic resistance into five parts.
In the first part, I want to explain why we have to treat TB with drugs at all.
I don't mean to suggest that people unlucky enough
to develop TB should go without treatment.
Rather, the question is,
why do we have to wait for people to get TB?
Why can't we prevent the disease in the first place?
This is important background to this story because,
if we use drugs less frequently,
then resistance to these drugs would emerge more slowly.
We would, in effect,
prolong the therapeutic life of our best antibiotics.
To see how and why we use TB drugs today,