Martin Kulldorff and colleagues have developed and operated real-time disease surveillance systems based on electronic records. In an article published in the open-access medical journal PLoS Medicine, they now report a new and very flexible approach for early disease outbreak detection.
The method, called the "space time permutation scan statistic," is an extension of a previous method of detecting outbreaks called scan statistic. The problem with this previous method is that it works only under certain circumstances, for example if there is a uniform population at risk (with the same number of expected disease cases in every square kilometer), or if quite a bit is known about the variation in factors such as age and disease susceptibility that occurs in that population. The new method doesn't need any of that: it can detect disease outbreaks when only the number of cases is available.
In their article, Kulldorff and colleagues illustrate the utility of the new method by applying it to data collected from hospital emergency departments in New York City. The researchers analyzed diarrhea records from 2002, and did both a "residential analysis" (based on the home address of the patients) and a "hospital analysis" (based on hospital locations). The former has more detailed geographical information, the latter maybe be better able to
Contact: Paul Ocampo
Public Library of Science