The Global Crisis of Drug-Resistant Tuberculosis and Leadership of China and the BRICS by Institute of Medicine

Author:Institute of Medicine
Language: eng
Format: epub
Tags: Health and Medicine: Global Health
ISBN: 9780309285995
Publisher: The National Academies Press
Published: 2014-03-08T00:00:00+00:00

MDR, XDR, AND UNTREATABLE TB IN AFRICA 3

Martie van der Walt, Interim Director, Tuberculosis Epidemiology and Intervention Research Unit, South African Medical Research Council; and Professor, Department of Internal Medicines, Faculty of Health Sciences, University of Pretoria, South Africa, highlighted the challenges of DR TB, including what has been termed “untreatable” TB, in the African context. The world has made great progress in reducing TB incidence, prevalence, and mortality, she said. However, progress in responding to DR TB remains low. During 2011, in the 27 HBCs, 60,000 MDR TB patients were diagnosed, and this number is a large underestimation, van der Walt said. Furthermore, the average rate of XDR TB among these patients is 9 percent.

Although Africa has a small percentage of the world’s population, it has a high burden of both TB and DR TB, along with high HIV infection rates. According to WHO (2012), the success rate for MDR TB treatment for Africa in general is only about 45 percent, and the death rate is higher than in any other WHO region. The default rate also is relatively high, which is a concern because defaulted or intermittent therapy drives drug resistance.

Of the 43 African countries covered in the WHO report, only 10 have culture capability, and only for FLDs. This limitation contributes to a marked lack of data for many African countries. Also, many countries do not treat TB with kanamycin and ofloxacin and therefore do not test for XDR TB.

Only two laboratories in Africa, both in South Africa, perform second-line DST. Some other countries in the region can perform first-line DST, but they do not do so universally because the cost of both the testing and the drugs is prohibitive. In addition, clinicians have limited experience treating patients with SLDs, and many are concerned about overlapping toxicity with HIV drugs.

The two laboratories in South Africa that perform second-line DST—the National Health Laboratory Service and van der Walt’s institution—are in Gauteng province in the north. Although the highest burden of TB is in the Eastern Cape and KwaZulu-Natal provinces, South Africa is fortunate to have a good specimen transportation system, such that specimens from even the most remote parts of the country can be delivered to one of these laboratories for DST within 3 days.

One reason for the low coverage of DST in African countries is uncertainty about when and whom to test. For example, when should a sample be collected for second-line DST? Should universal screening be conducted at case finding, at treatment initiation, or at regular intervals thereafter? Should attention be focused on particular populations, such as those who default, relapse, or do not culture convert? Should health care workers or other high-risk populations be tested? Should all patients with any rifampicin resistance undergo full DST? “I personally think this is the way to go,” said van der Walt. “The technology isn’t there, but we need to have a point-of-care microarray test that will give us, within a couple of minutes, results. Of course, then we also need the drugs.

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