John M . Colford

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A major challenge in tuberculosis control is the diagnosis and treatment of latent tuberculosis infection. Until recently, there were no alternatives to the tuberculin skin test (TST) for diagnosing latent tuberculosis. However, an alternative has now emerged in the form of a new in-vitro test: the interferon-gamma assay. We did a systematic review to(More)
Many studies have reported the results of interventions to reduce illness through improvements in drinking water, sanitation facilities, and hygiene practices in less developed countries. There has, however, been no formal systematic review and meta-analysis comparing the evidence of the relative effectiveness of these interventions. We developed a(More)
RATIONALE Although interferon-gamma (IFN-gamma) assays are promising alternatives to the tuberculin skin test (TST), their serial testing performance is unknown. OBJECTIVE To compare TST and IFN-gamma conversions and reversions in healthcare workers. METHODS We prospectively followed-up 216 medical and nursing students in India who underwent baseline(More)
CONTEXT Mycobacterium tuberculosis infection in health care workers has not been adequately studied in developing countries using newer diagnostic tests. OBJECTIVES To estimate latent tuberculosis infection prevalence in health care workers using the tuberculin skin test (TST) and a whole-blood interferon gamma (IFN-gamma) assay; to determine agreement(More)
Systematic reviews and meta-analyses synthesize data from existing primary research, and well-conducted reviews offer clinicians a practical solution to the problem of staying current in their fields of interest. A whole generation of secondary journals, pre-appraised evidence libraries and periodically updated electronic texts are now available to(More)
Conventional tests are not always helpful in making a diagnosis of tuberculous meningitis. We did a systematic review and meta-analysis to establish the summary accuracy of nucleic acid amplification (NAA) tests for tuberculous meningitis. We searched six electronic databases and contacted authors, experts, and manufacturers. Measures of diagnostic accuracy(More)
OBJECTIVE In vitro interferon-gamma (IFN-gamma) assays have emerged as novel alternatives to the tuberculin skin test (TST) for the diagnosis of latent tuberculosis (TB) infection. These assays have been evaluated in low incidence countries, mainly in adults, and have been shown to be more specific than TST. Because few studies have been done in high(More)
BACKGROUND Poor sanitation is thought to be a major cause of enteric infections among young children. However, there are no previously published randomized trials to measure the health impacts of large-scale sanitation programs. India's Total Sanitation Campaign (TSC) is one such program that seeks to end the practice of open defecation by changing social(More)
The incidence of acute gastrointestinal illness (AGI) attributable to public drinking water systems in the United States cannot be directly measured but must be estimated based on epidemiologic studies and other information. The randomized trial is one study design used to evaluate risks attributable to drinking water. In this paper, we review all published(More)
BACKGROUND The choice of optimal implant fixation in total hip replacement (THR)--fixation with or without cement--has been the subject of much debate. METHODS We performed a systematic review and meta-analysis of the published literature comparing cemented and uncemented fixation in THR. RESULTS No advantage was found for either procedure when failure(More)