GeneXpert for TB diagnosis: planned and purposeful implementation.

Xpert MTB/RIF is a major advance for TB diagnostics, especially for multidrug-resistant (MDR) TB and HIV-associated TB. But implementation concerns including cost, technical support requirements, and challenging demands of providing second-line TB drugs for diagnosed MDR-TB cases call for gradual, careful introduction based on country circumstances.

Viewpoint: Why and how tuberculosis control should be included in health sector reviews.

Sector-wide approaches (SWAps) are currently implemented in several, predominantly highly donor-dependent low-income countries, particularly in Sub-Saharan Africa. SWAp intends to enhance health sector performance, especially efficiency, effectiveness, coherence and sustainability. SWAps have been criticized for not being able to produce tangible results and the credibility of a SWAp would increase substantially if such results in terms of health services outputs could be demonstrated. We argue that the monitoring of tuberculosis within the SWAp reviews held to assess sector performance deserves a higher profile. Tuberculosis constitutes in the first place and one of the major public health problems in most of the countries, where SWAps have been introduced, but provided that the programme is integral part of the sector policy and financial management, the indicators used for monitoring TB control programmes can also be used as excellent proxies for monitoring overall health sector performance.

Comparison of PCR with the routine procedure for diagnosis of tuberculosis in a population with high prevalences of tuberculosis and human immunodeficiency virus.

Direct smear examination with Ziehl-Neelsen (ZN) staining for the diagnosis of tuberculosis (TB) as employed in most low-income countries is cheap and easy to use, but its low sensitivity is a major drawback. The low specificity of chest X-rays, used for the diagnosis of smear-negative TB, risks high levels of overdiagnosis. Major advances in molecular techniques, which rapidly identify mycobacterial DNA in sputa, may overcome these obstacles. In this study, the AMPLICOR PCR system was used to diagnose pulmonary TB in a developing country with high prevalences of both TB and human immunodeficiency virus (HIV). The sensitivity and specificity of this technique were compared to those of the usual diagnostic techniques. Sputum specimens were collected from 1,396 TB suspects attending the Rhodes Chest Clinic, Nairobi, Kenya. The specimens were analyzed for the presence of Mycobacterium tuberculosis by PCR; culture on Löwenstein-Jensen medium was used as the "gold standard." All culture-positive samples were genotyped to identify the mycobacterial species. The sensitivity and specificity of PCR were 93 and 84%, respectively. HIV status did not affect the sensitivity of PCR. A total of 99.7% of the true smear-positive and 82.1% of the true smear-negative TB patients were correctly identified by PCR. PCR detected M. tuberculosis in 11.7% of the culture-negative suspects, 60% of which had one or two PCR-positive sputum specimens. Of the 490 positive cultures, 486 were identified as M. tuberculosis. The high sensitivity of Amplicor PCR merits usage in a clinical setting with high TB and HIV burdens. Thus, PCR can be considered as an alternative to ZN staining in combination with chest X-ray for diagnosis of TB; however, cost-effectiveness studies and operational studies are required to support an evidence-based decision of introducing PCR for TB control in high-burden environments.

A Piot model to analyse case management in malaria control programmes.

At the beginning of the 21st century, malaria remains one of the most important public health problems in the world. An important control strategy to address this burden is adequate case management of malaria patients. The success of this strategy, however, does not solely depend on diagnosis and treatment, but also on a sequence of steps that patients have to take when they are ill. Only when patients go through all these steps successfully will they be cured. In this paper, a model is presented in which these steps are described. The model provides a framework for analysing this type of malaria control strategy and for identifying the most critical challenges faced. Furthermore, the model is used to analyse recent literature on case management as part of malaria control programmes in order to highlight current knowledge, core issues and constraints, and to make recommendations for programme development and research.