A study published today in The New England Journal of Medicine provides compelling evidence that extensively drug-resistant tuberculosis (XDR TB) is spread from person-to-person in the KwaZulu-Natal province, South Africa from 2011-2014. The study was conducted by a team of researchers from Emory University, the U.S. Centers for Disease Control and Prevention, Albert Einstein College of Medicine, and the University of KwaZulu-Natal in South Africa and was funded by the U.S. National Institute of Allergy and Infectious Diseases at the National Institutes of Health. It builds on a growing body of evidence showing that person-to-person transmission, not just inadequate treatment, is driving the spread of drug-resistant TB.

South Africa is experiencing a widespread epidemic of XDR TB, the deadliest form of TB, including a tenfold increase in cases between 2002 and 2015. The study found that the majority of cases (69 percent) in high HIV- and high TB-burden areas happened due to person-to-person transmission rather than inadequate TB treatment in South Africa. By using social networks analysis, the study identified numerous opportunities for transmission not only in hospitals, but also in community settings, such as households and workplaces. The study has important implications for efforts to prevent drug-resistant TB, which have traditionally focused on ensuring that patients receive accurate and complete TB treatment.

"These findings provide insight as to why this epidemic continues despite interventions to improve TB treatment over the past decade. Public health and research efforts must focus more intensely on identifying and implementing additional or new interventions that halt transmission in hospitals and community settings," says Neel R. Gandhi, MD, associate professor of epidemiology at Emory's Rollins School of Public Health.

The study included 404 XDR TB patients in KwaZulu-Natal, South Africa and was led by a team of researchers including Gandhi and Sarita Shah, MD, MPH, of of CDC's Division of Global HIV & TB. Researchers examined the role of transmission by combining robust genotyping methods with social network and epidemiologic analysis. The study is the first of its kind, bringing together these multiple state-of-the-art methods to study XDR TB transmission in a high-incidence setting.

"These findings are further proof that we need to better detect, prevent, diagnose, and treat drug-resistant TB," says CDC Director Tom Frieden, MD, MPH. "TB resistant to last-resort drugs is spreading through hospitals and homes, at work, and in other places in this high burden community. The only way to stop this disease is by improving infection control and rapidly finding and effectively treating people with TB." What is XDR TB?

Drug-resistant TB is a significant global epidemic. Reported in 105 countries, XDR TB is resistant to at least four of the key anti-TB drugs. In most settings, treatment is effective less than 40 percent of the time, with death rates as high as 80 percent for patients who also have HIV.

Interrupting the spread of TB can be particularly challenging in countries most affected by the disease. In settings with limited resources, measures to prevent the spread of TB such as contact tracing, implementation of effective infection control measures, improved ventilation in hospitals and better training for healthcare workers, can be difficult.

Study authors suggest that breaking the cycle of transmission of drug-resistant TB requires a greater focus on infection control efforts - while also maintaining global programs to quickly detect and effectively treat all people with TB.

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About Emory University

Emory University is one of the nation's leading private research universities and a member of the Association of American Universities. In addition to its nine schools, the university encompasses The Carter Center, Yerkes National Primate Research Center and Emory Healthcare, the state's most comprehensive health care system. Learn more at http://whsc. emory. edu/ home

About the CDC CDC works 24/7 saving lives and protecting people from health threats to have a more secure nation. Whether these threats are chronic or acute, manmade or natural, human error or deliberate attack, global or domestic, CDC is the U.S. health protection agency.

HIV and TB are the world's two most deadly infectious diseases. The two epidemics are tragically interconnected, as TB is the leading cause of death for those living with HIV. CDC's Division of Global HIV & TB works with partners to tackle these two epidemics and to produce the greatest global health impact. More information on the treatment and prevention of XDR TB can be found at http://www. CDC. gov/ globalhivtb

About Albert Einstein College of Medicine

Albert Einstein College of Medicine, a part of Montefiore, is a premier research-intensive medical school dedicated to innovative biomedical investigation and to the development of ethical and compassionate physicians and scientists. Inspired by the words of our namesake, we have from our inception welcomed students, faculty, and staff from diverse backgrounds who strive to enhance human health in the community and beyond. This is an attribute in which Albert Einstein took great pride when consenting to the use of his name in conjunction with the medical school. At the core of the Einstein-Montefiore mission is the pursuit of social justice in meeting the healthcare needs of all individuals, including those from underserved communities. Learn more at http://www. einstein. yu. edu/

About The University of KwaZulu Natal

The University of KwaZulu Natal is one of only three African universities rated among the top 500 universities in the world and is committed to academic excellence, innovation in research and critical engagement with society. Formed in 2004, The University of KwaZulu Natal has almost 40, 000 students and is one of the largest universities in sub-Saharan Africa. The University offers a wide range of courses that prepare students for career opportunities in the local and global marketplace. Learn more at http://www. ukzn. ac. za/

About the National Institutes of Health (NIH)