Concern over spread of drug-resistant TB

Tuberculosis, a bacterial infection that typically attacks the lungs, is highly infectious and kills about half of those who catch it if left untreated.

To make matters worse, resistance to the infection has emerged because some people have not been properly treated.

Curing patients with drug-resistant tuberculosis is expensive, prolonged and in some cases impossible.

Experts say that without new drugs the spread of drug-resistance strains will threaten decades of progress in eradicating the deadly disease.

Al Jazeera’s Tarek Bazley reports.