Tuberculosis is a major public health problem in South Africa and, due to its high infectivity, is posed to become a larger threat than HIV/AIDS. The incidence of TB infection continues to increase dramatically. According to the World Health Organization’s (WHO’s) Global TB Report 2008, South Africa had nearly 453,929 new TB cases in 2006, with an incidence rate of an estimated 940 per 100,000 population – a major increase from 1998’s incidence rate of 338 per 100,000 population. The spread of the epidemic has been greatly exacerbated by the development of both MDR (Multi-drug-resistant) and XDR (extensively-drug-resistant) strains, primarily documented in the KwaZulu Natal (KZN) province.
South Africa adopted the DOTS (directly observed treatment, short course) in 1996, after the National Department of Health realized that its previous TB control efforts had been ineffective. The DOTS strategy is the only that is globally recognized for effective TB control and is embedded in five principles, as described by the Tuberculosis Management Plan for South Africa:
1. Government commitment to sustained TB control activities.
2. Identifying infectious patients via sputum smear microscopy.
3. Direct observation of treatment for at least the initial two months of standardized short-course anti-TB treatment.
4. A regular, uninterrupted supply of standardized drug combinations.
5. A reliable, standardized reporting system which allows assessment of treatment results and overall program performance.
A multi-faceted approach to the TB epidemic is crucial due to its highly infectious nature via aerosol transmission. Identification of infectious patients is the necessary first step. If a patient has been in contact with a person with infectious tuberculosis, they are most often diagnosed via smear microscopy sputum examination after presenting with the appropriate symptoms. If acid-fast bacilli are detected, the patient is diagnosed with smear positive tuberculosis. Other diagnostic procedures, which are not commonly in use in South Africa, are chest x-rays, TB culture, and the tuberculin purified protein derivative (PPD) test.
It is crucial to initiate treatment of infectious patients as soon as possible in order to prevent further transmission. Standardized drug combinations include bactericidal, sterilizing, and resistance-prevention drugs.
Patients who are diagnosed with TB should also be tested for HIV as over 44% of new TB patients also test positive for HIV. Not only are HIV-positive persons far more likely to develop TB post exposure to TB bacilli, it is evidenced that TB infection also accelerates the progression of HIV disease. Patients who are simultaneously diagnosed with HIV and TB begin ARV treatment post-completion of the prescribed TB treatment regimen. HIV-positive patients who test negative for TB can be given TB preventative therapy, in the form of isoniazid prophylaxis, in order to reduce their risk of infection by up to 60%.
Even with DOTS policies in place, the emergence of MDR-TB and XDR-TB is an indicator of the poor implementation of South Africa’s TB Control Program. The number of laboratory-confirmed MDR-TB cases in South Africa has more than tripled from 2,000 cases in 2005 to 7,369 in 2007. The KwaZulu Natal (KZN) province, the epicenter of South Africa’s HIV/AIDS epidemic, has also been the most acutely affected by the emerging drug-resistant TB strains. In 2006, the WHO announced that a new extensively drug-resistant strain of TB (XDR-TB) had been detected in Tugela Ferry, a rural town in KZN. Of the 544 patients studied in the area in 2005, 221 were determined to have MDR-TB as defined as Mycrobacterium tuberculosis that is resistant to at least rifampicin and isoniaizid – two of the frontline drugs used to treat TB in South Africa. Of these 221 MDR-TB cases, 53 were determined to be XDR-TB as defined as MDR-TB plus resistance to at least three of the six classes of second-line agents. The median survival time from collection of the sputum specimen was 16 days for 52 of the 53 infected individuals – a previously unprecedented fatality rate for XDR-TB. A 2008 study that examined isolates collected from 2004-2007 showed that 5.6 percent of 17,615 TB cases were XDR-TB. The actual reported cases of XDR-TB have increased from 74 in 2004 to 536 in 2007. KZN continues to be the epicenter of the MDR/XDR-TB explosion; as of 2007 XDR-TB had been reported in at least 39 hospitals throughout the province with well over 30 new cases of XDR-TB being diagnosed each month in KZN alone.
It could be argued that the emergence of MDR/XDR-TB is evidence of a systematic failure of the global community to tackle a curable disease; in this case the South African government’s initial lethargic reaction to the crisis could be held accountable. The factors that have contributed to the emergence of MDR/XDR-TB are avoidable and merit urgent remediation. Well-documented factors include high treatment interruption rates and subsequent low cure rates due to inappropriate treatment regimens, irregular drug supply, incompetent health personnel, and/or non-adherence. Another significant factor fueling the MDR/XDR-TB outbreaks in South Africa is the lack of infection control in institutions. Not only are advanced and expensive environmental control procedures such as negative pressure rooms rare, the most basic measures of triaging patients and use of personal respiratory protection are under-utilized at best. Tuberculosis is recognized as a disease that preys upon social disadvantage causing infections to be concentrated in poverty-stricken areas. Observance of the Marianhill clinic in Durban showed that not one health care worker wore personal respiratory protection when attending to symptomatic TB patients – neither in the clinic nor at home visits.
The most critical factor in addressing MDR/XDR-TB is prevention through strengthening basic DOTS management and improving management of patients requiring re-treatment with second line drugs. An unprecedented strengthening of overall TB control is not just recommended – but imperative. In 2006, WHO urged a response to the XDR-TB outbreak akin to global efforts to control SARS and bird flu. XDR-TB poses a more serious global health-threat than HIV/AIDS due to its aerosol mode of transmission. There are many complicating factors at play including the ethical and human rights ramifications of mandated isolation and insufficient funding to reduce hospital crowding and improve DOTS management at all levels. As Singh argues, “Given the South African government’s poor track record in dealing with the country’s HIV/AIDS epidemic and what is at stake if it adopts a similar lethargic and denialist response to the country’s XDR-TB outbreak, the international community must be vigilant in monitoring the government’s response to this emerging crisis.” International complacency paves the way for the predictable next phase – a global pandemic of completely drug-resistant TB.
References:
Child Family Health International. Tuberculosis Management Plan for South Africa. HIV/AIDS and Health Care; Durban, South Africa. No date given.
Singh JA, Upshur R, Padayatachi N (2007) XDR-TB in South Africa: No Time for Denial or Complacency. PLoS Med 4(1): e50. doi:10.1371/journal.pmed.0040050.
USAID Health, Infectious Diseases, Tuberculosis, Countries, South Africa. www.usaid.gov/our_work/global_health/id/tuberculosis/countries/africa/safrica. Accessed 16 April, 2009.
