‘Virtually Untreatable’ tuberculosis threat rising, study finds

August 30, 2012 – HEALTH – Almost half of tuberculosis patients who received prior treatment were resistant to a second-line drug, suggesting the deadly disease may become “virtually untreatable,” according to a new study. Among 1,278 patients who were resistant to two or more first-line tuberculosis drugs in Estonia, Latvia, Peru, Philippines, Russia, South Africa, South Korea and Thailand, 43.7 percent showed resistance to at least one second-line drug, according to a study led by Tracy Dalton at the U.S. Centers for Disease Control and Prevention. The findings were published in the Lancet medical journal today. About 1.4 million people died from TB, the second-deadliest infectious disease globally after AIDS, and 650,000 cases were multi-drug resistant in 2010, according to the World Health Organization. Rising infection rates prompted the U.K. to announce in May it will require pre-entry tuberculosis screening for migrants from 67 countries seeking to enter the country for more than 6 months. “The global emergence of extensively drug-resistant tuberculosis heralds the advent of widespread, virtually untreatable tuberculosis,” the study authors said in the published paper. Previous treatment with second-line drugs was the strongest risk factor for resistance to these drugs, the authors said. The prevalence of drug resistance, which ranged from 33 percent in Thailand to 62 percent in Latvia, also correlates with how long second-line drugs have been available in each country. South Korea and Russia had the longest histories of availability — more than 20 years — and the highest rates of resistance. In contrast, Thailand, Philippines and Peru, where second-line drugs were introduced 10 years ago or less, had the lowest resistance rates. Unemployment, alcohol abuse and smoking were also associated with resistance to second-line injectable treatment across countries. This is one of the few studies that have followed patients with the multi-drug-resistant form of TB for several years, Justin Denholm, an infectious disease epidemiologist at the Royal Melbourne Hospital, said in a phone interview. Patients not taking their medicines properly is a major driver for resistance, said Denholm, who is studying TB transmission patterns in Australia’s Victoria state. –SF Gate