a six-log kill. (Six-log kill is also known as 1 × 106 kill rate, which means reducing the number of live organisms by 6 orders of magnitude). Bulk material can be physically removed by cleanup methods that will leave a residuum that could be destroyed with a six-log kill. If one can not precisely identify the amount of contaminating material present at the start of a cleanup, then defining a specific level of remediation in terms of a log kill rate becomes difficult.
The biological agent used in an attack might become known as a result of a perpetrator’s announcement, or it could be identified from physical recognition by trained personnel, from early presumptive test kit results, or from human symptoms. A rapid overt (announced) release will give rise to identification by physical and microbial analysis of substances obtained from obviously exposed surfaces. Health monitoring of exposed people is not likely to be necessary for identification. In the case of a covert release, environmental monitors, such as those that have been deployed in major cities as part of the BioWatch program or health monitoring of exposed people, might offer the first clues. The more likely scenario for detection of a covert release—based on past experience—would be the alarm raised by health professionals who would see an unusual disease such as anthrax or smallpox, or who might see several patients who are seriously and inexplicably ill.
Surveillance for increased incidence of common symptoms in targeted patient populations, known as syndromic surveillance, is one way to identify unusual clusters of disease that could result from an act of bioterrorism. Syndromic surveillance monitors the frequency of symptom complexes identified in patients before the confirmation of a medical diagnosis. The surveillance systems complement routine public health surveillance, and they commonly provide the advantage of near-real-time data entry, analysis, and reporting. The objective is to identify an attack as quickly as possible to allow for a rapid response and effective public health intervention. The alerts or warnings provided by the systems can initiate an epidemiological investigation to determine the source and extent of the exposure in the shortest possible time. Syndromic surveillance can be used to detect increases in influenza-like illness during periods of peak influenza A and B activity and of diarrhea and vomiting during periods of suspected norovirus and rotavirus transmission (Hefferman et al., 2004), but its ability to detect a bioterrorist attack has not yet been evaluated.
Substantial information can be obtained from microbial analysis of samples of serum, pus, scabs, and stools, as well as from environmental air and surface samples. A delay in identifying a decontaminating agent would afford the possibility of sustained agent viability and growth in mechanical spaces, crevices, and so on. Many types of sampling can be done, and different approaches are appropriate in different situations. The issues of cross contamination also must be