To print: Select File and then Print from your browser's menu --------------------------------------------------------------------------------------- Title: Predicting Tuberculosis Outbreaks Based on the First 2 Cases URL: http://www.pslgroup.com/dg/224BDE.htm Doctor's Guide July 1, 2008
NEW YORK -- July 1, 2008 -- Outbreaks of tuberculosis (TB) may be able to be identified by looking at certain characteristics of the first 2 patients, according to new research in the July issue of the American Journal of Respiratory and Critical Care Medicine. The research is the first to determine that patient characteristics might be used to predict outbreaks and thus more efficiently allocate limited public health resources The study showed that if the first 2 patients are diagnosed within 3 months of each other, live in urban areas, and if 1 or both are of sub-Saharan African origin, there is a 56% chance that the 2 cases will lead to a large outbreak of TB, whereas if the patients exhibit none of those characteristics, the odds are just 1%. "Early identification of clusters that could potentially become large could help focus TB control efforts, especially in low-incidence countries that approach the elimination phase of TB," wrote lead author Sandra V. Kik, KNCV Tuberculosis Foundation, The Hague, Netherlands. "The aim of our study was therefore to determine which characteristics of the first 2 cases can predict the development of a large cluster." Kik and colleagues analysed data from the Netherlands Tuberculosis Register and the National Institute of Public Health and the Environment from 18,200 patients with reported TB between 1993 and 2004. They discounted non-culture-confirmed cases, cases that could not be exactly matched between the 2 databases, and duplicate cases. They then determined which cases were a part of a cluster episode of 2 years and whether those cluster episodes were small (<=4) or large (>=5). In the final analysis, 622 cluster episodes were identified comprising of 1,756 individual cases, 54 of which were large clusters. "In 36 of the 54 (67%) large clusters, the first 2 cases were diagnosed within a period of 3 months, compared to 150 of the 568 (26%) in small clusters," Kik wrote. "The short time period between 2 successive patients was the strongest predictor. If 2 patients are diagnosed within 3 months of each other, and they belong to the same Mycobacterium tuberculosis cluster, this is a strong indication for an upcoming outbreak." In addition to having the initial 2 cases identified within 3 months of one another, if the 2 patients were under the age of 35, were of sub-Saharan African origin, or lived in an urban setting, they were also more likely to be a part of a large cluster. "The main advantage of using patient characteristics as predictors is that these are known shortly after diagnosis and easy to determine as this information is often part of the current registration system," said Kik. While noting that the specific predictive characteristics of the first 2-patient model may vary from country to country, the authors point out that their research methodology could be used to determine those characteristics with the most predictive power whatever the country, and thus have the potential to concentrate limited public health resources in the areas that may have the greatest public health impact. "This study confirms previous understanding that tuberculosis is a social, as well as infectious disease, that depends for its spread on the nature of human interactions and the social context," said John Heffner, MD, Providence Portland Medical Center, Portland, Oregon. "What is fascinating is that the authors identified quite early in a cluster outbreak specific social factors that predicted the rapidity and extent of disease transmission, which allows more focused interventions." SOURCE: American Thoracic Society --------------------------------------------------------------------------------------------- Copyright © 1999 P\S\L Consulting Group Inc. All rights reserved. Republication or redistribution of P\S\L content is expressly prohibited without the prior written consent of P\S\L. P\S\L shall not be liable for any errors, omissions or delays in this content or any other content on its sites, newsletters or other publications, nor for any decisions or actions taken in reliance on such content. --------------------------------------------------------------------------------------------- This news story was printed from *Doctor's Guide to the Internet* located at http://www.docguide.com --------------------------------------------------------------------------------------- Return to News Story Page This site is maintained by webmaster@pslgroup.com Please contact us with any comments, problems or bugs. All contents Copyright (c) 1998 P\S\L Consulting Group Inc. All rights reserved.