Findings and methodology are reported for a research project with the goal of developing a confirmatory diagnostic test for detecting fly artifacts that contaminate bloodstain evidence.
"Insect artifacts" are officially categorized as "bloodstains produced from insect activity." This definition encompasses any insect that interacts with a corpse or associated exuded blood; however, flies, ants, and cockroaches are the most common sources of insect artifacts. The problem with fly artifacts is that they may be indistinguishable from certain types of human bloodstains. Insect stains produced by fly regurgitation or fecal elimination are morphologically similar to impact (i.e., forward, back, and mist-like spatter), projected, sneezed, and expirated bloodstains. They cannot be reliably distinguished using presumptive or confirmatory tests for identification of human blood. The use of molecular methods, notably DNA typing for a person's identification, does not overcome these limitations, since viable human DNA can be extracted from fly stains. Thus, the inability to consistently and reliably distinguish insect artifacts from human body fluid stains poses a serious problem in distinguishing entomological contaminants at crime scene. Deficiencies in current methods are noted in this report. One approach that has not been explored is the development of confirmatory tests based on the chemical composition of insect-derived stains. The approach of the current project focused on polyclonal antibodies generated toward M. dom-3, a synthetic peptide demonstrated in this project's preliminary research to have the highest reactivity with the synthetic peptide and in detection of enzymes in fly regurgitate during preliminary testing. The resulting antibodies were used to develop western and dot blot preliminary testing. The resulting antibodies were then used to develop western and dot blot detection assays to distinguish fly artifacts from human bloodstains. The successful testing of this method is described. 15 references
Report (Grant Sponsored)
Date Published: August 1, 2019
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