Use of Host Factors in Microbial Forensics

This chapter illustrates central elements of the host response in a simplified fashion and describes a few representative examples that have a high potential of providing evidence. It may aid an investigation to distinguish a perpetrator from a victim who has been exposed to a particular microorganism or by-product, such as a toxin. Considerable advances have been made in the forensic analysis of microbes and toxins. These advances include sequencing, genomics, and microscopy. An underdeveloped and underutilized area in microbial forensics is how the host interacts with microorganisms in a way that provides unique signatures for forensic use. For investigative and forensic purposes, an immediate goal is to distinguish a potential victim and innocent person from a perpetrator and to distinguish between a naturally acquired or intentional infection. Two principal methods that are sufficiently developed are characterization of the humoral immune response and identification of vaccine-induced immunity or antibiotics that may be present in a possible perpetrator. The primary aims of a microbial forensics investigation are to identify the biological agent, its source, and the individuals responsible for the event. Analytic approaches differ when the suspected biothreat agent is encountered in a container or the environment, as opposed to in vivoin a human, animal, or plant. Analyses of trace elements, pollens, growth media, latent fingerprints, and microbial and nonmicrobial nucleic acids are all applicable to the container and environmental sample.