Scientists have found alarming levels of the lung disease tuberculosis in Africa, Asia, Europe and Latin America that are resistant to up to four powerful antibiotic drugs.
In a large international study published in the Lancet medical journal on Thursday, researchers found rates of both multi drug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) were higher than previously thought and were threatening global efforts to curb the spread of the disease.
"Most international recommendations for TB control have been developed for MDR-TB prevalence of up to around 5 percent. Yet now we face prevalence up to 10 times higher in some places, where almost half of the patients ... are transmitting MDR strains," Sven Hoffner of the Swedish Institute for Communicable Disease Control, said in a commentary on the study.
TB is already a worldwide pandemic that in 2010 infected 8.8 million people and killed 1.4 million of them.
Drug-resistant TB is more difficult and costly than normal TB to treat, and is more often fatal.
MDR-TB is resistant to at least two first-line drugs - isoniazid and rifampicin - while XDR-TB is resistant to those two drugs as well as a powerful antibiotic type called a fluoroquinolone and a second-line injectable antibiotic.
Treating even normal TB is a long process, with patients needing to take a cocktail of powerful antibiotics for six months.
Many patients fail to correctly complete treatment, a factor which has fuelled a rise in the drug-resistant forms.
Researchers who studied rates of the disease in Estonia, Latvia, Peru, the Philippines, Russia, South Africa, South Korea, and Thailand found that almost 44 percent of cases of MDR TB were also resistant to at least one second-line drug. Reuters