Laboratory aspects of bioterrorism-related anthrax--from identification to molecular subtyping to microbial forensics

During the bioterrorism-associated anthrax investigation of 2001 in the United States, 11 patients were diagnosed with inhalational anthrax and 11 more with the cutaneous forms of the disease. Over 125,000 specimens were processed at laboratories of the Laboratory Response Network including those at the Centers for Disease Control and Prevention. Although the 2001 anthrax investigation initially began as a public health investigation, the forensic aspect quickly became a preeminent component of the investigation. Whereas a public health investigation aims primarily to identify the causative agent and its source, so that appropriate and timely control and preventative measures can be implemented, a forensic investigation goes further to associate the source of the causative agent with a specific individual or group. In addition to identification and molecular characterization of the causative agents, which are the crucial components of forensic microbiology, there are many other requirements and activities that need to be in place for investigators to successfully complete a forensic investigation. These activities include establishment of quality assurance/quality control criteria and regular proficiency testing for all laboratories where evidence is analyzed; additional and/or specialized training in handling and processing samples in accordance with forensic microbiology criteria, not only for first responders but also for laboratory and other public health scientists; and establishing and maintaining repositories and databases containing isolates of diverse temporal and geographic origins to provide a comparative and diverse background for investigators to identify and track the origin and source of such agents.