Laboratory-guided detection of disease outbreaks: Three generations of surveillance systems

Context. - Traditional biothreat surveillance systems are vulnerable to incomplete and delayed reporting of public health threats. Objective. - To review current and emerging approaches to detection and monitoring of biothreats enabled by laboratory methods of diagnosis and to identify trends in the biosurveillance research. Data Sources. - PubMed (1995 to December 2007) was searched with the combined search terms "surveillance" and "infectious diseases." Additional articles were identi-fied by hand searching the bibliographies of selected papers. Additional search terms were "public health," "disease monitoring," "cluster," "outbreak," "laboratory notification," "molecular, " "detection," "evaluation," "genomics," "communicable diseases," "geographic information systems," "bioterrorism," "genotyping," and "informatics." Publication language was restricted to English. The bibliographies of key references were later hand searched to identify articles missing in the database search. Three approaches to infectious disease surveillance that involve clinical laboratories are contrasted: (1) laboratoryinitiated infectious disease notifications, (2) syndromic surveillance based on health indicators, and (3) genotyping based surveillance of biothreats. Advances in molecular diagnostics enable rapid genotyping of biothreats and investigations of genes that were not previously identifiable by traditional methods. There is a need for coordination between syndromic and laboratory-based surveillance. Insuf-ficient and delayed decision support and inadequate integration of surveillance signals into action plans remain the 2 main barriers to efficient public health monitoring and response. Decision support for public health users of biosurveillance alerts is often lacking. Conclusions. - The merger of the 3 scientific fields of surveillance, genomics, and informatics offers an opportunity for the development of effective and rapid biosurveillance methods and tools.