Volume 9, Number 10—October 2003
Syndromic Surveillance and Bioterrorism-related Epidemics
|Characteristicsa||Clinical recognitionb||Syndromic surveillancec|
|Duration and variability of incubation period
||Broader distribution of incubation period increases likelihood that patient with short incubation-period disease would be diagnosed before a statistical threshold of syndromic cases is exceeded.
||More narrow distribution of incubation period—leading to a steeper epidemic curve in the initial phase—increases likelihood that statistical threshold would be exceeded sooner.
|Duration of nonspecific prodromal phase
||Shorter prodrome increases likelihood of recognition or diagnosis at more severe or fulminant stage.
||Longer prodrome increases likelihood that increase in syndromic manifestations would be detectable and that recognition of more severe stage (at which a diagnosis is more apt to be made) would be delayed.
|Presence or absence of clinical sign that would heighten suspicion of diagnosis
||Presence increases likelihood of earlier clinical recognition and diagnosis (e.g., mediastinal widening on chest x-ray in inhalational anthrax).
||Absence decreases likelihood that diagnosis would be considered clinically, increasing opportunity for earlier detection by means of syndromic surveillance.
|Likelihood of making diagnosis in the course of routine evaluation||If diagnosis is apt to be made in the course of a routine diagnostic evaluation (not dependent on clinical suspicion of specific bioterrorism infection), early diagnosis through clinical care is likely.||If diagnosis is dependent on the use of a special test that is unlikely to be ordered in the absence of clinical suspicion of diagnosis, then diagnosis in clinical care may be delayed, increasing the opportunity for early detection through syndromic surveillance.|
aInfection or disease attributes that may affect detection of an epidemic.
bIncreases likelihood of initial detection through routine clinical care and reporting.
cIncreases likelihood of initial detection through syndromic surveillance.
1For interval calculations, if reported event dates were discrepant in different case reports, dates reported by Jernigan et al. (13) were used.