TB Outbreaks May Be Predicted by First 2 Cases

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TUESDAY, July 1 (HealthDay News) -- It may be possible to predict tuberculosis (TB) outbreaks by examining characteristics of the first two cases of the disease, Dutch researchers report.

Based on their analysis of data on more than 18,200 Dutch patients with reported TB between 1993 and 2004, the researchers concluded there's a 56 percent chance of a large TB outbreak if the first two patients: are diagnosed within three months of each other; live in urban areas; and if one or both patients are of sub-Saharan African nationality.

"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, an epidemiologist at the KNCV Tuberculosis Foundation in The Hague. "The aim of our study was therefore to determine which characteristics of the first two cases can predict the development of a large cluster."

The study was published in the current issue of the American Journal of Respiratory and Critical Care Medicine.

"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," Kik said.

While the specific characteristics of the two-patient model may vary from country to country, the research methodology used in this study could be used to identify characteristics with the most predictive power in any country, the study authors said.

"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," Dr. John Heffner, past president of the American Thoracic Society, said in a prepared statement.

"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," he said.

More information

The U.S. Centers for Disease Control and Prevention has more about TB.