The World Health Organization on Wednesday said that a "virtually untreatable" strain of TB has been discovered. Dr. Paul Nunn of the WHO said that extreme drug resistant TB (XDR TB) has been seen worldwide, including in the U.S., Eastern Europe and Africa, although Western Europe has had no cases.

Nunn is blaming the failure to implement treatment strategies for the emergence of the new TB strain. TB experts have convened in Johannesburg, South Africa, to discuss how to address the problem.

Statistics show that TB accounts to 1.7 million deaths worldwide per year, but researchers expressed fear of the emergence of the drug-resistant strain.

Experts say drug resistance is caused by poor TB control, through taking the wrong types of drugs for the incorrect duration.

Multi-drug resistant TB (MDR TB), which describes strains of TB that are resistant to at least two of the main first-line TB drugs, is already a growing concern.