Spatial epidemiology and the detection of spatial clusters of dengue in Paraíba: a comparison between the flexible Scan and circular Scan methods

Abstract

Background

Spatial statistics are used to help health managers make decisions, informing the rate of occurrence of diseases in the population and highlighting when they reach values beyond expectations.

Objective

To understand the functioning and applicability of Spatial Statistics Flexible Scan and Circular Scan by comparing their results in the detection of spatial clusters using real epidemiological data of dengue in the state of Paraíba – Brazil.

Method

The detailed process for applying the flexible scan and circular scan statistics for detecting significant dengue risk areas (clusters) in Paraíba, between 2009 and 20013, was described using the software FLeXScan and SaTScan.

Results

Both methods showed the highest frequency of clusters detected at high risk in the western region of the state, in all the years analyzed, considering the risk maps of dengue incidence in Paraíba, between 2009 and 2013.

Conclusion

The flexible scan and circular scan statistics are practically similar in terms of efficiency in detecting clusters of dengue. However, there were problems of overestimation in the circular Scan method and underestimation in the flexible Scan method in the detection of clusters. It is also worth highlighting that these spatial statistics help health managers locate the regions of disease aggravation, making it more effective to direct combat actions in a politically correct manner.

Keywords:
spatial agglomeration methods; circular scan statistics; flexible scan statistics; epidemiology of dengue