The accurate estimation of the postmortem interval (PMI) is one of the most important determinations in a forensic investigation of decomposing human remains. Forensic entomology has gained popularity in death investigation due to its reliability and precision in the estimation of the minimum postmortem interval (mPMI). Forensically significant insects are mainly necrophagous species, which feed only on decomposing animal matter, and the most common necrophagous insects are the blowflies (Diptera: Calliphoridae). Estimations of the mPMI by entomological methods are made using the known developmental rates of various species of blowfly and via the successional patterns of the carrion insect community in a given region. It is generally assumed that blowflies oviposit quickly after death, so in many cases this time may equate to the time since death. The precision of mPMI estimations based on the developmental rates of blowflies often relies on this assumption. Rainfall may effect decomposition by inhibiting access of insects to the cadaver or carcass for oviposition. The current study investigated the effects of rainfall on blowfly activity, behavior, and overall decomposition of decaying animal material in an outdoor environment in the northeastern United States, conducted at the Boston University Outdoor Research Facility (ORF). It was hypothesized that natural rainfall, typically light to moderate in the geographic area of study, will disturb initial blowfly activity by acting as a physical barrier, diminishing access to the remains, and creating a delay in colonization and subsequent larval development. This hypothesized delay would result in an underestimation of the mPMI by entomological methods when rainfall has occurred. Also examined were several questions about the nocturnal behavior of blowflies and their activity in heavy rain. In the experimental trial 12 pig (Sus scrofa) heads were exposed under normal conditions (N; no rain controls), and 15 pig heads were exposed under rainy conditions (R; rain treatment), split into uncovered (N, n=6; R, n=5), covered (NC, n=5; RC, n=5), and covered partially (RCP, n=5) treatments. Additionally, there were three pig heads used in a preliminary trial and three pig heads exposed in an active rain trial. Generally, the results show that while a negative correlation exists between the amount of rainfall experienced and the coded number of flies observed, the light to moderate rainfall typical of many rainy days in the northeastern Unites States will not totally inhibit blowfly activity or disturb established maggot masses. A one-way analysis of variance (ANOVA) determined that there was no statistically significant difference (p > 0.05) between the N, NC, R, RC, and RCP treatments in the number of days it took to reach the advanced decomposition stage. While constant, heavy rainfall may inhibit blowfly activity; the results suggest that the irregularity of natural rainfall would rarely produce the conditions necessary for this to make a significant impact estimation of the PMI by entomological methods, although further studies are needed to confirm this conclusion. The results show a positive correlation between solar radiation and the coded number of flies observed. Time of day as a function of the coded number of flies observed during the first 48 hours of exposure forms a bimodal bell curve, confirming that blowflies are diurnal in their natural environment. Additionally, evidence of scavenging by turkey vulture (Cathartes aura) and some unknown animal(s) was observed. The results of this study illustrate the complicated, multivariable nature of the process of decomposition. This study provides preliminary data on the effect of rainfall on blowfly activity and overall decomposition, while future studies will be required to determine the effects of the duration and the intensity of rainfall.

In the forensic DNA field, quantitative PCR (qPCR) is commonly used to quantify the amount of deoxyribonucleic acid (DNA) in evidentiary samples. Though sensitive, this method is prone to error. Electrochemistry-based biosensors have been described as a possible alternative to qPCR. To this end, this work aims to develop a biosensor for forensic quantification by chemisorbing oligonucleotides functionalized to methylene blue onto the surface of gold screen-printed electrodes. Prior to this, the surface characteristics of the screen-printed gold electrode are examined through the use of a well-known redox probe Ru(NH3)62+/3+. Cyclic voltammetry (CV) and Square Wave voltammetry (SWV) were used to measure the current signal. The Randles-Sevčik equation was used to relate the area of the electrode with the current signal. Surface examinations of the gold screen-printed electrodes suggested these electrodes are suitable for use as a forensic DNA biosensor. Attempts to bind the oligonucleotide to the gold electrode were conducted. Though binding was successful, the resultant SWV signal suggested methods to chemisorb DNA onto gold surfaces require optimization.

The present research examines the effects of multiple different implements on long bones to determine if there is a point at which blunt force trauma becomes distinguishable from hacking trauma. Limb bones of the white-tailed deer (Odocoileus virginianus) were used in this research as a substitute for human bone. In addition to the use of purchased tools, seven of the implements used in the present research were created and designed to imitate the size and impact angle of other surfaces possibly found in hacking and blunt force trauma. A hacking machine was used to inflict trauma on the long bones at a consistent, controlled level of force. The resulting trauma was then photographed and analyzed to determine if there is a macroscopically distinguishable point at which an implement will inflict characteristics of blunt force trauma, with no visible hacking trauma characteristics. The analytical observations of the trauma involved scoring for elements such as hacking characteristic appearance as well as the amount of fracturing and fragmentation. The author hypothesized that when the angle of the implement’s striking surface reaches 60 degrees, the trauma would consist of blunt force characteristics and not of hacking characteristics, and a V-shaped kerf would cease to appear. The author also hypothesized that there would be an increase in comminuted fractures in more blunt blade angles, while hacking trauma would exhibit more transverse and oblique fractures. The present study found that there was a statistically significant relationship between the composite hacking scores and the blade angles (the striking surface of the implement), with a p-value of 0.011. The author concluded that blunt force trauma and hacking trauma can be distinguished by the composite hacking scores, with a score of one indicating blunt force implements and scores of three or four indicating hacking implements. The entrance widths of the impacts also had a statistically significant relationship with the implement blade angles, with a p-value of 0.037. When the elements were bisected as a result of the impact, the data generated was characterized into having bisected into three identifiable fragments or a minimum of four identifiable fragments. With regards to the data for elements with three identifiable fragments, it was found that there was a statistically significant relationship between fragmentation and the implement blade angle, with a p-value of 0.036. When examining the visibility of a V-shaped kerf in the bones, the author concluded that there is a statistically significant relationship between the blade angles and the visibility of these kerfs, with the visibility decreasing around the 60 blade angle (p-value = 0.003). With regards to the fracture patterns, there was a correlation between the appearance of transverse fractures, with a decrease in more blunt blade angles (p-value = 0.004). Additionally, the author discovered a correlation between clean cut impact site appearances and smaller blade angles, as well as with crushing and fragmentation correlating to more blunt blade angles. The data from this research should assist in establishing guidelines to determine the type of trauma inflicted in forensic cases of hacking trauma and blunt force skeletal trauma.

Molecular phenotyping is the use of informative genetic variation to estimate appearance. This concept can be applied in a forensic context to predict the appearance of suspects or decayed deceased individuals, which would otherwise remain unidentifiable. This concept has importance in a local context, as approximately 300 individuals remain unidentified, after conventional identification techniques, at Salt River Mortuary, every year. Ancestry Informative Markers (AIMs) are genetic variants with DNA which have been commonly associated with pigmentation phenotypes, and thus has value in predicting skin tone, hair colour and eye colour. This research study aimed to design and optimise an assay to genotype 13 AIMs associated with pigmentation, and then demonstrate the value of this assay by applying it to a case example and qualitatively predicting appearance. Primers were designed and PCR assays optimised to amplify each region, followed by Sanger sequencing on a case example. The case was that of an abandoned neonate, with unknown sex and ancestry. A comparison of the obtained genotypes to previous literature was performed to qualitatively estimate the skin tone, eye colour and hair colour of the decedent, which was not only in agreement with the forensic pathologist’s interpretation of sex and ethnicity, but provided richer detail with regards to ancestry, skin tone, eye colour and hair colour. The PCR assays were then further optimised into four multiplex assays with the intention of genotyping these AIMs by two SNaPshot® PCR assays (Applied Biosystems) in a larger control cohort to model the relationship between these AIMs and melanin index more objectively. Unfortunately, the scope of this research project did not allow for the completion of this additional aspect. Overall, these results indicate that these 13 AIMs have potential to predict pigmentation phenotypes of South African individuals. However, genotyping and modelling of the effects of these AIMs should be performed on a large cohort to further strengthen this conclusion.

Pesticide-related poisonings place a burden on the public health system in low- and middleincome countries. Notification of pesticide poisonings and deaths is a legal requirement in South Africa, however, our understanding of the prevalence and type of pesticides involved in poisoning cases remains limited. This is further complicated by the emergence of ‘street pesticides', which are unlabelled and illegally sold toxic pesticides. It is important to understand the role of these and other pesticides in local poisonings, and mortuary data provides an important resource to be able to investigate pesticide-related mortality specifically. This study aimed to build on previous research conducted at the Salt River mortuary (SRM) by expanding and updating our understanding of pesticide-related fatalities within the West Metropole of Cape Town. A retrospective, cross-sectional review of all unnatural death cases admitted to the SRM between January 2016 and December 2019 (inclusive) was conducted so as to identify pesticide-related deaths for further investigation. A total of 15 761 cases were admitted to SRM over the 4-year study period (mean: 3941 cases per annum). From this total, 92 cases (0.58%) were identified as pesticide related. Most decedents were male (59.8%), with the cohort's mean age being 26.2 years (range: 2 months to 66 years). The majority of cases were suicides (60.8%), and terbufos (an organophosphate) was detected in 50 cases (54.3%). Pesticiderelated fatalities were found to predominately occur in lower socio-economic areas. According to the data adults and adolescents are most at risk of being exposed to the harmful effects of these harmful compounds. Using a holistic approach to investigating pesticide-related fatalities could provide important clues that assist in gaining a better understanding of the factors that influence pesticide-related incidents. Combined efforts from healthcare practitioners and forensic investigators could help inform policy-makers on ways to minimise the use or distribution of pesticide compounds.

Fire-related fatalities pose many investigative challenges, in part due to their fragility. This can be managed with the creation of protocols, specific to the environment in which they are implemented. Currently, no protocol for the recovery and handling of fire-related fatalities exists in Cape Town, South Africa. Additionally, the challenges, risk factors, and resources present at forensic scenes in the area have not been documented. From April to December of 2015, fire-related death scenes were attended with Salt River Forensic Pathology Laboratory, which serves the West Metropole of Cape Town. Details of the fatal fire scenes were noted, including the challenges faced, and the settings in which the fires occurred. Emphasis was placed on methodologies used to recover, handle, and transport remains, and the availability and utilisation of resources. The affect these methodologies had on the condition of the remains between scene and autopsy was assessed. In total 32 fire-related death scenes were attended, with 48 decedents recovered. Males predominated (64.6%), and the majority were young adults (75%). Accidental deaths were most prevalent (79.2%), however a fire-related suicide and homicides highlighted the importance of thorough investigation. Informal housing constituted 68.8% of the fatal fire scenes and presented unique scene constraints, including no direct road access at 50% of these scenes. Investigative limitations included: inadequate interagency communication, resulting in a lack of collateral information available at autopsy; deficient scene and contextual documentation; non-standardised recovery methodologies; insufficient availability and utilisation of resources (including safety equipment); and no specialised personnel (e.g. forensic pathologists/ anthropologists) conducting scene recovery. The majority of cases (60.4%) were further fragmented or fractured by time of autopsy, illustrating the necessity for improvement of current methodologies and the importance of the involvement of forensic anthropologists in recovery of fragmentary remains.

In order to support identification of crime victims in South Africa, new methods need to be sought. If victim identification involving fingerprints, DNA or dental records are not possible, facial approximation is often the only alternative. In order to gain necessary background data for the identification of unknown individuals, e.g. for facial approximations, facial features of modern South Africans need to be investigated and shape-influencing factors identified. New imaging technologies have opened the possibility of including living, dentate individuals, as specimens in skeletal collections are often edentulous. The aim of this dissertation was to assess chin shape variation and the factors influencing it, in black and white South Africans. In the first part, the mental eminence was assessed by applying a morphoscopic sex estimation technique, to test its applicability to 105 dry mandibles from the Pretoria Bone Collection, and to the respective micro-focus X-ray computed tomography (micro-XCT) scans, obtained at the Nuclear Energy Corporation South Africa. Fleiss Kappa, Cohen’s Kappa and Wilcoxon Signed-Rank tests were applied. Score frequencies and observer performance were analysed. In the second part, the chin shape was assessed by quantifying its morphology, applying geometric morphometric methods to 291 retrospectively collected CBCT scans. The scans were obtained for medical reasons from dental patients, at the Oral and Dental Hospital, University of Pretoria. The possible influences of ancestry, sex, age and allometry on the chin shape were tested, using MAN(C)OVA, 50-50 MANOVA, permutation tests and discriminant function analysis (DFA) on the x-, y- and z-coordinates of the anatomical landmarks. The morphoscopic method to estimate sex on the mental eminence, originally applied to bone, was found to be applicable to micro-XCT scans as well, and observer performance did not vary greatly between the two modalities. However, an observer’s personal affinity to assess 3D images, the level of experience and tendency to over- or underscore in one of the two modalities cannot be excluded and should be individually tested. The chins of black females and white males had the highest probabilities of correct sex estimation. Ancestry, age and allometry were significant chin shape influencing factors in the complete sample. In addition, ancestry influenced the chin shape significantly within the sex groups, allometry within the ancestral groups. Sexual dimorphism significantly influenced chin shape in the complete sample on the bony menton and in the ancestral groups. Most results from both parts of the study concurred, except the influence of age. With the increasing availability of imaging techniques in forensic anthropology, researchers are motivated to look for new, and validate existing, methods in 3D. By assessing the applicability of a morphoscopic sex estimation technique to micro-XCT scans, and by investigating the chin shape variation using CBCT scans, the present study contributed to the quantifiable biological profiling methods involving 3D imaging techniques in South Africa. This study could encourage further research on all five traits of the morphoscopic method in bone and 3D surfaces, and of the soft-tissue shape of the chin in the same populations. / Dissertation (MSc)--University of Pretoria, 2020. / Anatomy / MSc (Anatomy) / Unrestricted

No description available.

A death scene investigation (DSI) forms an integral part of the inquiry into death, particularly for sudden unexpected death of infants (SUDI). Global guidelines exist for DSI, however, it is unclear how many countries adhere to them, and to what extent they are followed. Therefore, a systematic literature review was undertaken to assess the scope of SUDI DSI performed internationally. It was found that national protocols have been established in some countries, and have shown value in guiding medico-legal examinations. Further, South Africa did not routinely perform DSI for SUDI cases, nor was there a protocol. This was largely attributed to the burden of SUDI cases as well as the lack of resources. Therefore, this study aimed to suggest realistic and feasible ways to improve DSI for local SUDI cases. This research study consisted of three phases: 1) A twoyear review of medico-legal case files from SUDI cases investigated at Salt River Mortuary; 2) The prospective observation of DSI for ten SUDI cases, using a semi-structured checklist; and 3) he distribution and analysis of a survey regarding SUDI DSI to all registered, qualified forensic pathologists in South Africa. The results showed that the SUDI death scenes were assessed in 59.2% of cases at Salt River Mortuary, with inconsistent levels of documentation or photography. Death scenes were never investigated in cases where the infant was pronounced dead on arrival at a medical facility. In both scene observations (n=10) and retrospective analysis (n=454) only one case incorporated a re-enactment, but the majority of infants were moved prior to DSI. The findings support the need for a standardised approach to DSI, coupled with specialised training for staff. Based on the available resources, this should focus on the establishment of guidelines pertaining to photography, handling medicine and scene reconstruction, as well as accurate use of relevant documentation.

Background: Complementary and Alternate Medicines (CAMs) in South Africa are not yet subjected to the same rigorous testing required for allopathic (prescription) medication, yet they are freely available as over-the-counter medicines. Past research has shown the presence of a banned drug, sibutramine in natural anorectics and a schedule 6 prescription drug, sildenafil, found in natural erectile dysfunction preparations. Methods: Initially, 26 exhibits (18 erectile dysfunction medicines and 8 anorectics) were screened for active pharmaceutical ingredients using high performance liquid chromatography tandem mass spectrometry. An AB SCIEX 3200 TRAP® linear ion-trap quadrupole mass spectrometer was used to detect and subsequently quantitate these active pharmaceutical ingredients using a targeted multiple reaction monitoring mode. Samples were extracted with 50% v/v methanol in water. A method for the quantitation of sildenafil was subsequently partially validated. The intra- and inter-assay precisions were evaluated and the linearity of the method was investigated in the range of 20 ng/mL to 2000 ng/mL. The method was then successfully applied to a random selection of CAMs. A random sample (n=61) of erectile dysfunction CAMs were selected for quantitation from two different clusters. Cluster 1 comprised of supermarkets and cluster 2 of pharmacies. Results: The validation method for sildenafil showed that the limit of detection was 1.09 ng/mL and the limit of quantitation was 20 ng/mL. The correlation co-efficient and bias were less than 20%. Initial screening of the 26 exhibits indicated that sildenafil was present in 12 of the 18 samples tested and sibutramine in 6 of the 8 anorectics. Of the later 61 exhibits tested, 43 tested positive for sildenafil. The mass of sildenafil per sample ranged from 1.09 ng/mL to 123.7 mg/sample. Conclusion: The lack of label content, regulation and legislation exposes the consumer to the risk of consuming an active pharmaceutical ingredient which may very likely have an adverse effect on their health. There is a need to raise public awareness to the potential dangers of unregulated CAMs, encourage doctors to become more aware of their patients' consumption of CAMs and to motivate the Medicines Control Council to follow through with their deadlines for the regulation of CAMs.