Forensic Science Institute

Disease Surveillance and Projected Expansion in Climatic Suitability for Trypanosoma cruzi, the Etiological Agent of Chagas Disease, in Oklahoma

The vector-borne hemoflagellate parasite Trypanosoma cruzi infects seven million people globally and causes chronic cardiomyopathy and gastrointestinal diseases. Historically, T. cruzi was endemic to Central and South America, but is now found throughout the southern United States and across 43 countries globally. There are three reports of T. cruzi in wild raccoons and dogs in Oklahoma, but its endemicity in the state is poorly studied. We suspect Mexican free-tailed bats (Tadarida brasiliensis) contribute to the endemicity of T. cruzi in Oklahoma by their annual migration from Central America to North American maternity roosts. During the summer of 2017, we sampled 361 Mexican free-tailed bats at three maternity roosts in Oklahoma for T. cruzi. We collected wing tissues and extracted DNA, amplified target T. cruzi DNA by PCR using the primers TCZ1/TCZ2, and observed amplification by gel electrophoresis. We detected T. cruzi DNA in one juvenile Mexican free-tailed bat resulting in a prevalence of 0.27% in the 361 sampled bats. The positive sample was sequenced at Eton Biosciences, confirmed as T. cruzi, and uploaded to GenBank (MG869732). This finding is the first reported detection of a wild bat naturally infected with T. cruzi in Oklahoma, suggests Mexican free-tailed bats can contribute to T. cruzi endemicity via migration between endemic foci, and provides insight on the endemicity of T. cruzi in underrepresented endemic areas. To better understand the potential impact of global climate change on the future epidemiology of T. cruzi in Oklahoma, we used the program MaxEnt to develop an ecological niche model for T. cruzi and five widespread Triatoma vectors based on 19 bioclimatic variables and 546 published localities within the United States. We modeled regions of current potential T. cruzi and Triatoma distribution, and regions projected to have suitable climatic conditions under a Representative Concentration Pathway (RCP 8.5) scenario by 2070. Regions with potential suitable climatic conditions for T. cruzi, T. indictiva, T. lecticularia, T. protracta, and T. sanguisuga are predicted to increase within the United States and Oklahoma by 2070. Regions with potential suitable climatic conditions for T. gerstaeckeri are predicted to increase within the United States but not in Oklahoma by 2070. Our findings agree with previous literature and confirm that climate change will influence the expansion of T. cruzi and important Triatoma vectors in Oklahoma and the United States.

Matthew D. Nichols – 2018

Posted on August 15, 2019 by Dr. Mark McCoy

Comparative Subtidal and Supratidal Taphonomic Changes in the Elemental Components of Marine Vertebrate Bones using Energy Dispersive X-Ray Spectroscopy and Principle Component Analysis: Ecological and Forensic Applications

Individuals and agencies of multiple disciplines have evolved interests which result in the studies and research of marine mammals as well as other protected marine dwellers such as sea turtles. Aside from wildlife conservation, a logarithmic increase in interest to these protected animals have been the side effect of trade for profit to fund activities targeted at human populations as acts of terror. Wildlife trade and trafficking have aided terrorist groups in the funding of ammunition and weapons of mass destruction. This study focuses on observations made by analysts while examining remains of protected animals that may be involved in trade or trafficking on the black market. Recent observations have found that marine organisms like the sea turtle and porpoise display signs of advanced taphonomy and even premature fossilization following decomposition. In this study, skeletal remains from submerged marine vertebrates including a porpoise, seal, sea turtle, and a cow control were sampled in order to determine a plausible explanation for these observations. The specimens were necropsied prior to submersion, and the bones of each vertebrate were segregated with  respect to species. Periodic samplings took place throughout the course of this study. Using the Scanning Electron Microscope (SEM), the bone specimens were examined for topographic changes and analyzed for elemental composition. Among the different elemental aspects of bone composition, a list of elements was compiled and monitored for change throughout the course of this study.

Caitlyn B McElreath – 2018

Posted on August 15, 2019 by Dr. Mark McCoy

Bloodstain Pattern Analysis with an Emphasis on Infrared Photography to Visualize Impact and Satellite Spatter on Denim

Correctly classifying bloodstain patterns is a crucial element of providing conclusions in
the field of Bloodstain Pattern Analysis, because the type of bloodstain pattern speaks to how the
bloodstains were created. Very few studies have compared impact spatter specifically to satellite
spatter. The research needs outlined by SWGSTAIN include a better understanding of
discriminating between bloodstain patterns containing small stains (present in both impact and
satellite spatter), how blood interacts with different types of fabric, and developing new methods
of visualizing and enhancing bloodstains (2011). Further, the Organization of Scientific Area
Committee (OSAC) on BPA, which absorbed SWGSTAIN, outlines needs to reduce the
subjectivity in BPA classification and understanding the interaction between blood and fabrics
(OSAC, 2019). The only study to the author’s knowledge that specifically compares satellite
spatter to impact spatter is Short’s 2016 study, which compared the two patterns on several
different fabrics. However, Short was not able to visualize spatter on denim, due to dark color of
the denim and lack of contrast between the blood and denim surface. The current study used infrared photography to view simulated satellite spatter and
impact spatter on 100% cotton denim and poster board. Both quantitative and qualitative data
were collected. Two-way ANOVA, Cochran-Mantel-Haensel, and chi-square tests were
performed on the data. Several comparisons found either a significant interaction, difference, or
association between independent and dependent variables, depending on the test performed and
the type of data analyzed. Overall, by utilizing the methods in this study, it is possible to
differentiate between simulated impact and satellite spatter on denim fabric.

Christina Traverso – 2019

Posted on August 15, 2019 by Dr. Mark McCoy

Cold Case Investigations: A University Initiative

Despite technological advancements and improved methodologies in

forensic science and investigative practices, cold cases are a growing problem in the

United States. Although there has been a surge in interest in solving cold cases due to

advancements in technology, there has been very little research conducted on cold case

investigation methodology. Many agencies lack the personnel and resources to devote

adequate attention to cold cases. Federal dollars spent on cold case resolution in recent

years focused only on those cases that could benefit due to improvements in DNA

analysis techniques. The literature demonstrates that advances in other forensic

disciplines can provide answers in unsolved crimes. Additionally, it has been shown that

investigations often benefit simply from a case file review by a fresh set of eyes. This

research was conducted to develop best practices guidelines for a cold case program in a

collegiate setting in partnership with a law enforcement agency. Information from a

variety of sources was reviewed to develop guidelines that would address the needs of all

parties to such a collaboration. A manual entitled “Best Practices & Guidelines for the

Implementation and Management of a Cold Case Program in a Collegiate Setting” was

produced as a result of this research. This manual is intended for use by institutions of

higher learning with a focus on educating students for careers in the field of forensic

science and will assist instructors in implementing an upper level course for students to

engage in the review and analysis of case files pertaining to unsolved crimes designated

as cold cases by the collaborating law enforcement agency. Such a course is ideally

suited to graduate students and as an in-house practicum for seniors.

Amber L. Fortney – 2019

Posted on August 15, 2019 by Dr. Mark McCoy

Necrophagy in Honey bees (Apis mellifera); A Forensic Application of Scent Foraging Behavior for the Protection and Conservation of Endangered Species

Scent training and field detection trials were conducted to determine if honey bee (Apis mellifera) foraging behavior could be employed as a practical application in the location of vertebrate carrion for use in interdiction and recovery efforts of illegally trafficked wildlife. Resource recognition and querying trials consisted of two components. Honey bees were trained to associate chemical compounds found in decaying tissues with a high-quality food source via introduction of the compounds into a sugar solution. Randomized scented and non-scented sugar solution choices were subsequently provided to hived bees at varying distances within a rural outdoor study area. Following initial forager recruitment by scouts, twice the number of bees were observed feeding at carrion-scented stations.

Additional field trials performed using wildlife carrion reinforced experimental results. Scent trained scout bees showed a marked interest in decomposing wildlife remains by aerially investigating and landing on the carrion. These findings demonstrate honey bee retention of carrion sensory recognition capabilities and support the cabronid wasp theory of honey bee evolutionary origins. Applications for forensic remains detection, wildlife trafficking interdiction, and endangered species conservation are indicated.

Brian D. Morice – 2019

Posted on August 15, 2019 by Dr. Mark McCoy

Chemical Analysis of Processed Human Hair Extensions for Use in Forensic Casework

This study proved that there is a chemical difference between processed human hair extensions and natural human head hair. This was indicated by differences observed in UV-Vis, GC/MS, and NMR spectra between natural human head hair and processed human hair extensions. There were peaks present in the spectra of the processed human hair extensions that were not present in the spectra of the control natural human head hair samples. These peaks showed a chemical difference between the samples. This chemical difference can be used to differentiate samples in a forensic laboratory, which could change how hair is analyzed for casework. Being able to chemically identify a human hair as an extension is invaluable during an investigation and might exclude the hair as probative evidence.

Cortney Schartz – 2019

Posted on August 15, 2019 by Dr. Mark McCoy

The Forensic Value of Processed Human Hair Extensions

Three brands of processed human hair extensions were evaluated microscopically and genetically for their probative value in forensic casework.  Microscopic analysis of hair morphology determined that the internal and surface characteristics of the human hair extensions were consistent with human head hair and failed to identify any distinguishing features (pitting, striations, indentations, internal variations) that differentiated the extensions from natural human hair.  Chemical analysis identified carbon, oxygen, sulfur, aluminum, and calcium as the main elemental components of the extensions which is consistent with human hair.  There were no elements detected that were unique to the processed human hair extensions.  mtDNA extracted from the hair extensions was sequenced and compared to the revised Cambridge sequence (rCRS) to identify single nucleotide polymorphisms (SNPs).  SNPs were used to assign haplotypes and distinguish regional affiliations associated with the extensions in an attempt to establish the ethnicity of the hair donor’s maternal lineage.  Hair extensions were associated with multiple geographic regions.  Sequencing also identified hairs from multiple donors in each package.

Caitlin Porterfield – 2014

Posted on August 15, 2019 by Dr. Mark McCoy

Training Events – 2019

  • Presumed Compliance, Oklahoma Gang Investigators Association, Feb 21-22
  • The Art of Perception, NY Times Best Selling Author Amy Herman, Mar 12
  • Oklahoma Missing Persons Day, Apr 13
  • Asset Forfeiture, U.S. Attorney’s Office, Western District,, Apr 16
  • Bloodstain Pattern Analysis, FBI Dallas, June 15
  • IAI Conference, June 5-7

Posted on June 24, 2019 by Dr. Mark McCoy

About Capstone Reflections

The purpose of the Capstone reflection is to identify the  “SO WHAT?” So what did you learn during the Capstone? Whom does it affect? How might it be useful? How did your experience connect to your academic work? How did you grow intellectually and/or personally? Since the Capstone was a highly individual experience, the students reflections will also be unique; addressing those specific expectations, problems, skills learned and transformational experiences.

Posted on April 17, 2019 by Dr. Mark McCoy

Training Events – 2018

Moot Court Training, DNA Solutions, March 16

FS Workshop for Nation Conference on Undergrad Research, April 4-7

Seminar on Discovery and Evidence for DEA and ATF with WDOK, May 9

Workshop on LC/MS for OSBI, Tulsa PD and OKC PD, May 14

Continue Reading

Posted on April 16, 2019 by Dr. Mark McCoy
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