Browsing by Subject "Biomedical Forensic Science"
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- ItemOpen AccessA pilot study on stature estimation of the South African male population using the post mortem Lodox® Xmplar-dr imaging device at the Salt River Forensic Medico-Legal Laboratory(2022) Venketsamy, Yomika; Heyns, Marise; Mole, Calvin; Dinkele, ElizabethIdentification of deceased individuals is of paramount importance in the South African constitution, with victim identification noted as a human right. Stature has been used to assist identification of an individual when skeletal remains are recovered. The usefulness of stature estimation using conventional x-rays, magnetic resonance imaging (MRI) and computed tomography (CT) measurements of long bones in a modern population has been researched in a number of countries, however, there has been limited research conducted on Lodox® bone scans as an added tool for stature estimation in the South African population. Forty-nine deceased males aged 21 to 61 years were scanned with Lodox® within 24 hours of entering Salt River Mortuary for a scheduled autopsy. Total stature was initially measured on the autopsy table with an embedded ruler. The body underwent a full body digital x-ray using the Lodox® Xmplar DR device. To measure length of bones on the Lodox® scans, full body images were exported in DICOM (Digital Imaging and Communication in Medicine) format and five long bone maximum lengths i.e. humerus, radius, ulna, femur and tibia of the bodies were digitally measured using the integrated Lodox® software. Lodox® image scan measurements found that the humerus, femur and tibia were the most statistically significant correlators of stature, individually. The univariate linear regression showed strong statistical significance for the humerus, femur and tibia with estimating stature. Multiple linear regression with the combination of humerus and ulna; femur and tibia; humerus, femur and tibia were statistically significant in determining stature. However, a combination of ulna and radius and the combination of all five bones overall regression was not statistically significant. Univariate and multiple linear regression formulas were created for the South African male population using Lodox® image scan measurements. Correlation and paired t-tests showed significant correlation between manual stature measurement at the mortuary and Lodox® measurements for stature.
- ItemOpen AccessA retrospective analysis of post-mortem procedures of sudden unexpected death in the young investigated at Salt River Forensic Pathology Services, Cape Town(2022) Hamadziripi, Dirk M; Heathfield, Laura; Mole, CalvinSudden unexpected death in the young (SUDY) is the demise of a seemingly healthy individual aged between one and 40 years. The scope of SUDY investigation varies and there is little research regarding SUDY at Salt River Mortuary (SRM). Accordingly, the objectives of this study were to determine the number of SUDY cases admitted to SRM, document the scope of investigations, and identify candidates for retrospective molecular autopsies. A total of 1088 cases were admitted between 1 January 2010 and 31 December 2015, representing 3.3% (1088/32812) of the entire case load, 30 were excluded as the files were missing. Full autopsies (56.7%; 600/1058) were preferred to partial autopsies (5.6%; 59/1058) and external autopsies (37.7%; 399/1058). The most utilised ancillary tests were LODOX imaging (86.6%, 916/1058) and toxicology (34.8%; 368/1058). Specificity of cause of death was seen to be significantly associated with the extent of autopsy. A total of 35.7% (378/1058) of the cases were established as candidates for molecular autopsy on the criteria of being undetermined, having unspecific causes of death or having specific causes of death that are deemed hereditary. Findings of this study show that SUDY cases do not always undergo all ancillary tests coupled with retention of biological samples. These findings provide insight into the current gaps in the investigation of SUDY cases at SRM and highlight areas for improvement.
- ItemOpen AccessA retrospective descriptive analysis of fatal ground level falls and falls from a height: A 5-year review(2022) Chonyera, Rumbidzai Lorraine Stephanie; Mole, CalvinFalls have been identified as the second leading cause of accidental deaths in the world and has become a public health issue. Depending on the manner and height at which the fall occurs, different injury patterns are observed, and these are useful for the determination of circumstances surrounding death. The aim of the present study was to determine the demographic characteristics, prevalence and injury patterns associated with ground level falls and falls from a height. A five-year (1 January 2014 - 31 December 2018) retrospective descriptive review of fatal fall cases investigated at Salt River mortuary was conducted. The prevalence and patterns of injuries were assessed with regard to fall height, impacting surface and victim demographics. There were 360 fall related deaths. Fall prevalence in the Western Metropole District of Cape Town is 3.72/ 100 000 population. Ground level falls were prevalent among the elderly while younger individuals fell from greater heights. There is an association between the sex of an individual and height from which they fall. Accidental falls were more common and no association was found between the alleged manner of death and sex. Skeletally, a higher frequency of fractures was observed in ground level falls while the head, chest and pelvis were affected in the high level falls. additionally, an association was observed between injuries sustained and fall heights. There is a significant difference in fracture proportions between the heights in the pelvic and lower extremities and no significant difference in head, spine, chest and upper extremities. As expected, trauma associated with falls varies based on the height of the fall. Lower extremity fractures are common in ground level falls however a challenge remains for falls from a height as there is a need for more studies to focus on the diverse patterns that occur in these.
- ItemOpen AccessA retrospective study investigating risk factors for sudden unexpected death in the young(2022) Oghenechovwen, Ogheneochuko Mary; Heathfield, Laura J; Mole, CalvinSudden unexpected death in the young (SUDY) is the unanticipated demise of individuals aged between 1 and 40 years. In South Africa, these deaths are referred for forensic investigation. The primary aim of this study was to retrospectively investigate the frequency of known risk factors in SUDY cases admitted to Salt River Mortuary in Cape Town and explore differences between males and females. There were 1 088 SUDY cases identified with 0.9% (10/1 088) missing files. Reviewed cases were n=1 078, 62.6% (675/1 078) males, and 37.4% (403/1 078) females; 83.5% (901/1 078) adults and 16.4% (177/1 078) children, accounting for 5.6% of total admissions between 1 January 2010 and 31 December 2015. Despite the predominance of males, significantly more females (61.8%) were obese (p < 0.05). At least one primary medical condition was present in 53.7% of cases, with the leading conditions being tuberculosis (11.9 % of adult males), epilepsy (11.7% of adult males; 10.3% of female children), HIV (10.7% of adult females) and asthma (11.1% of male children). In the subset of the study population where information was available, before death, 74% of individuals were reported to have experienced prodromal symptoms; 37.6% of males and 32.4% of females did not seek medical intervention following symptoms. Information regarding a family history of sudden death was known in 237/1078 cases. In 3.2% of these cases, a family history of sudden death was reported. Significantly more males than females reported the use of tobacco, alcohol, and other illicit drugs (p < 0.05). More females were unemployed (p < 0.05). Interventions based on lifestyle modification, social support, pharmacologic needs, and awareness should be targeted at individuals with the above profiles, especially those with a family history of sudden death, as they may be high-risk groups. Findings from this study contribute new and relevant local reference data for SUDY risk profiles of males and females admitted to Salt River Mortuary.
- ItemOpen AccessAssessing the accuracy of the zygoma for estimating ancestry using geometric morphometrics in a South African sample(2019) Tawha, Tafadzwa Primrose Rudo; Gibbon, Victoria E; Dinkele, Elizabeth; Mole, CalvinThe large number of unidentified, decomposed and skeletonised remains found in South Africa (SA) necessitates relevant and reliable methods to assist in victim identification. Ancestry estimation from unknown skeletal remains is essential when reconstructing a demographic profile of a missing person. In the SA population, estimating ancestry is problematic as standards developed internationally rarely apply to the local, biologically heterogenous population. Craniofacial morphology is known to be ancestrally distinct and studies are yet to explore shape and size variation in the zygomatic bone of the SA population. The aim of this study was to assess ancestral variation in zygomatic shape and size in a SA population using three-dimensional geometric morphometric analyses. A sample of 158 individuals were analysed from Bantu-speaking (BA), European (EA) and Mixed Ancestral (MA) South African groups. Males were larger in size than females, but no size differences were observed between ancestral groups. Significant shape differences were observed between ancestral groups, while none were observed between males and females. BA and MA individuals had narrower, shorter and more anteriorly projecting zygomas than EA individuals. The zygoma was shown to accurately distinguish EA (84%) from BA (81%), and MA (80%) from EA (68%) individuals, but unreliably distinguished BA (60%) from MA (66%) individuals. This is likely correlated to the historical peopling of SA and historical forced racial classification. Age-related changes and antemortem tooth loss did not confound the ancestral variation in size, despite minor changes in zygomatic shape being associated with these two factors. These confounders did not impact ancestry estimation accuracies, further suggesting a minor impact on overall zygomatic shape. Furthermore, the patterning of ancestral variation in the zygoma revealed the need for further research to distinguish between the biologically heterogenous ancestral groups in SA.
- ItemOpen AccessAssessment of 13 Forensic Molecular Markers for skin colour in South Africa(2018) Pharo, Gavin; Heathfield, LauraMolecular 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.
- ItemOpen AccessAssessment of the suitability of blood samples collected for toxicological analysis for subsequent genetic analysis: A follow-up study one year later(2018) Musiyandaka, Fungisai Lorraine; Heathfield, Laura; Davies, BronwenDrug usage, both of a recreational or pharmaceutical nature, is common, however the abuse of such substances is an international problem. In the Western cape, South Africa, the burden of drug-related fatalities is high compared to the rest of the country. The provincial Forensic Pathology Service may encounter cases where drug-related fatalities are unclear whether death was accidental or suicidal, or drug toxicity is inconsistent with the medical/social history. This may be due to genetic alterations with drug metabolism and it has been suggested that genetic analyses may be the next step in these cases. However, toxicology results from the National Forensic Chemistry Laboratory in the Western Cape may be delayed by months to years, meaning that upon interpretation of toxicology results, there is no chance to obtain another blood sample from the deceased individual for genetic analysis. It was therefore important to determine the suitability of blood samples collected and handled in toxicology environments for subsequent genetic tests. Previously, blood samples from 30 post-mortem cases were collected into two red-top (no additives), two grey-top (sodium fluoride/potassium oxalate) and one purple-top (EDTA) tubes. Samples from one red-top and one grey-top tube underwent toxicological analysis, followed by DNA analysis, while the remaining tubes (controls) underwent DNA analysis immediately. All samples were then stored for approximately one year, prior to this study. The DNA analysis was repeated on all blood samples (n = 150) and results were assessed in terms of storage time and tube type. DNA was not significantly degraded in any of the samples; however, DNA from red-top tubes had significantly lower concentrations compared to that from grey-top tubes (p < 0.001), regardless of whether the sample had undergone toxicological analysis. The very low yields of DNA from red-top tubes posed substantial challenges for PCR-based analysis, resulting in poor quality Sanger sequencing results. Some DNA from grey-top tubes, passed the quality assessments and hence further work is required to provide an informed decision on which tube type is better suited for genetic analyses.
- ItemOpen AccessThe assessment of the utility and impact of sexual assault evidence collection kits (SAECKS) as DNA evidence in suspected cases of rape(2014) Cupido, Danielle; Heyns, MariseThe results from this study show the value of good basic medical practices in documentation of injuries, rather than more costly DNA evidence, in assisting courts in rape cases. However, the researchers do argue that in South Africa, as a middle-income country with a high percentage of non-intimate partner rapes, there would be an advantage in improving the system to collect and analyse DNA evidence rather than abandoning it completely. These results taken together suggest that DNA evidence can assist in signifying that sexual act has transpired however it is more likely that convictions will occur if evidence of physical injury is available, as DNA evidence cannot reveal if consent was obtained or not. As stated above South Africa has one of the highest rates of rape worldwide.
- ItemOpen AccessComparison of sars-cov-2 rapid tests and formal serological testing on deceased persons in Cape Town Metro(2022) Carlisle, Tayna; Heathfield, Laura; Martin, LornaThe COVID-19 disease was declared a global pandemic in 2020 and since, it is unclear how many people have truly been infected. Additionally, there is a paucity of research into post mortem antibody testing. An antibody screening tool that is suitable for use in the mortuary setting would go a long way to better document previous COVID-19 infections in deceased persons for surveillance purposes, which would add value to public health systems. This pilot study aimed to explore the use of the Sure Screen COVID- 19 IgG/IgM Rapid Test Cassette in a deceased population, and to compare it to the gold- standard antibody tests in South Africa, to determine the most suitable form of antibody testing for post-mortem samples. Thirty cases, with suspected COVID-19 infection in their lifetime, were recruited from Salt River and Tygerberg mortuaries following informed consent from next-of-kin. Positive COVID-19 PCR (PCP) test confirmation for SARS-CoV-2 was located for 19 of the participants. Blood was collected at autopsy into serum separator tubes which, were found to separate better when centrifuged immediately after sample collection. Sure Screen testing was carried out alongside Roche Diagnostics Elecsys Anti-SARS-CoV-2 and Abbott Architect SARS-CoV-2 IgG Assay. For the confirmed PCP cases, Elecsys' sensitivity was the highest at 94.74%, followed by Sure Screen IgG (78.95%). There was only one case with PCP confirmation with a negative Elecsys result and, in this instance, there was a longer interval between death and autopsy (8 days). No variables relating to time intervals between PCP, death and antibody testing were found to significantly influence the antibody test results. Overall Roche's Elecsys performed the best on our cohort of post-mortem serum samples, followed by Sure Screen, and lastly, Abbott's Architect assay. Based on these results alone, the Sure Screen test demonstrates potential as a screening tool in the mortuary setting, which should be followed up with Roche's Elecsys assay for diagnostic confirmation. However, it is recommended that the sample size be expanded to add weight to this preliminary conclusion.
- ItemOpen AccessComplementary and alternate medicines: a forensic analysis of the potential adulteration of over-the-counter anorectics and "lifestyle" medicines in South Africa(2017) Catterson, Sandra Lynne; Davies, Bronwen; Smith, Peter; Aukloo, Kathrina MendozaBackground: 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.
- ItemOpen AccessConstructing a DNA profile frequency database for South Africa using the Qiagen Investigator 24plex GO! Kit(2018) Nel, Lorraine; Heathfield, Laura JDNA profiling is routinely used in the forensic setting to identify individuals during criminal and medico-legal investigations. Its principle is based on the molecular analysis of DNA to produce a string of alpha-numeric characters which can be matched to a known reference sample. The use of allele frequencies from the background population aids the statistical interpretation of a match and can be used to calculate the random match probability. In South Africa, allele frequency data for the background population is currently limited, which can hinder the discriminatory value of DNA evidence, particularly when only a partial profile is obtained. Therefore, the aim of this study was to generate DNA allele frequency data for four South African population groups using the QIAGEN Investigator® 24PLEX GO! Kit, which has six markers for which data does not yet exist for the South African population. Full forensic DNA profiles were generated from 655 unrelated individuals from four population groups in South Africa: Black African (n = 172), Coloured (n = 195), Indian/Asian (n = 88) and White (n = 200). A 98% first time success rate was observed using the direct PCR approach. Allele frequencies were significantly different between all four population groups at three markers (D8S1179, D2S1338 and D2S441) after a Bonferroni correction (ρ < 0.001) and sixteen novel alleles were observed. Two genetic anomalies were observed, namely triallelic patterns at the TPOX marker (n = 9) and a null allele at amelogenin (n = 1). While the sample size for the Indian/Asian population group was limited in this study, the data generated here nevertheless prospects to contribute towards the data currently published for South Africa. This, in turn, will allow for more DNA markers to be analysed during forensic casework in South Africa, as the data for its statistical interpretation is now available.
- ItemOpen AccessThe contribution of respiratory pathogens to Sudden Unexpected Death in Infancy(2016) Ishimirwe, Elyse Sandrine; Kaba, Mamadou; Heyns, MariseBackground: Sudden unexpected death in infancy (SUDI) is among the most frequent causes of mortality in infants less than one year of age. Respiratory infections have been identified as the most frequent cause of death in these infants. Yet, the broad range of respiratory pathogen that might be involved in SUDI is poorly studied. This study aimed to investigate the incidence of the respiratory pathogens in SUDI. Methods: A prospective study was carried out on SUDI cases admitted to Salt River Forensic Pathology Laboratory from February 2015 through May 2015. Cerebrospinal fluid, pericardial fluid and lung biopsy were collected from each study participant during post-mortem examination. Total nucleic acids were extracted on the automated QIAsymphony platform. The microbial diversity was investigated using a commercialized multiplex real-time PCR assay, the "FTD Respiratory pathogens 33" kit. This assay is able to detect 21 viruses, 11 bacteria and one fungus. In each real-time PCR run, a positive and non-template sterile water were included as controls. Results: Thirty SUDI cases (median age, 3 (interquartile range (IQR): 2 - 8 months) were included in the study. Twenty participants were males. Positive microbiological results from at least one of the three samples were obtained in 28 cases (93%). According to the type of sample, respiratory pathogens were detected in almost all the lung biopsies (93%), while it was only detected in 60% and 50% of the cerebrospinal and the pericardial fluids, respectively. The median cycle threshold value was lower in lung biopsies (30 (IQR: 28 ‒ 35)) compared to both cerebrospinal (34 (IQR: 30 ‒ 36)) and pericardial fluids (35 (IQR: 33 ‒ 35)) (p= 0.039). In lung biopsies, the most commonly detected bacteria were K. pneumoniae (47%, 14/30) and M. catarrhalis (20%, 6/30). H. influenza (7%, 2/30) and M. pneumoniae (7%, 2/30) were the bacteria often detected in pericardial fluid and cerebrospinal fluid, respectively. Human Metapneumovirus was the most frequently virus detected in all three sample types assessed, accounting for 33% (10/30) in cerebrospinal fluid, 37% (11 /30) in pericardial fluid and 57% (17/30) in lung biopsy samples, respectively. A single type of pathogen was detected n seven of the 28 positive cases. Conclusion: This study highlights the potential implication of respiratory infection in SUDI and it reports one of the highest incidences of respiratory pathogens in SUDI cases. In addition, it is the first to report the high incidence rate of Human Metapneumovirus in SUDI cases. The findings also showed that the majority of SUDI cases are associated with synergetic interaction of multiple respiratory infections. However, data related to histopathology and bacterial culture were not available. A broad range of respiratory pathogens should be included in the routine investigation of SUDI cases with more sensitive diagnostic methods.
- ItemOpen AccessDevelopment and partial validation of a method for the quantification of benzodiazepines and antidepressants in whole blood, serum and urine by liquid chromotography - Tandem mass spectrometry(2015) Pieters, Janke; Smith, PeterThe aim of this project is to develop a single quantification method for certain benzodiazepines, opiates and antidepressants in whole blood, serum and urine by LC-MS/M5 and to consequently validate the analytical method for official use in the Division of Pharmacology at the University of Cape Town.
- ItemOpen AccessDevelopment of a method for the screening and quantification of methamphetamine, and its major metabolite amphetamine, in hair using liquid chromatography-tandem mass spectrometry(2015) Johnston, Jenna; Smith, Peter; Heyns, MariseHair has, over recent years, become widely recognised as an alternate or complementary matrix to blood and urine for drug analysis. Hair analysis offers a wider detection window after drug exposure than blood or urine testing and can provide a long-term history of an individual’s drug use. There are several practical applications of hair analysis for drugs including workplace drug testing, doping control, driving licence re-granting, drug-related deaths and drug-facilitated crimes. As a result hair analysis is currently being performed within various toxicological fields in laboratories around the world. However, before the start of this study no hair analysis for drugs was being performed in South Africa. Therefore, the main aim of this study, as stated in Chapter 1, was to develop a method for the detection and quantification of drugs of abuse, specifically methamphetamine and amphetamine, in hair using High Performance Liquid Chromatography coupled to Mass Spectrometry.
- ItemOpen AccessDNA barcoding of forensically important blow flies (Diptera: Calliphoridae) within the Western Cape of South Africa(2019) Kulenkampff, Kyle Sieghard; Heathfield, Laura; Heyns, MariseIn forensic entomology, determining species identity is a crucial step towards estimating post mortem interval. DNA barcoding can aid in the identification of unknown forensically relevant species, and this requires the comparison of DNA barcodes to reference data from known species. However, there is a lack of DNA barcode reference data of forensically relevant Calliphoridae species in the Western Cape (South Africa). DNA barcodes were generated for the COI and ITS2 markers for 41 forensically relevant Calliphoridae specimens, representing seven species from six localities in the Western Cape: Chrysomya albiceps (n = 3), Chrysomya chloropyga (n = 8), Chrysomya marginalis (n = 5), Chrysomya megacephala (n = 7), Hemipyrellia fernandica (n = 1), Lucilia cuprina (n = 8) and Lucilia sericata (n = 9). This data was combined with that from Cooke et al. (2018) (n = 40), and subjected to rigorous statistical and phylogenetic analyses. Phylogenetic analysis which combined data for both COI and ITS2 barcodes returned monophyletic clades for each species with increased support when compared to using each barcode individually. This combined dataset was able to discriminate between L. cuprina and L. sericata with full support (100% pP), which was not achieved previously. DNA barcodes were evaluated for intra- and inter-specific variance as well as haplotype patterning. No haplotype patterning was observed for either barcodes across sampled localities. Lastly, a single-blinded approach was used to assess the dataset, whereby DNA barcodes from ‘unknown’ specimens were correctly identified using this reference data. These identifications were more accurate than those using GenBank® or BOLD, highlighting the importance of using locally relevant reference data. This study has contributed new data pertaining to DNA barcodes for seven Calliphoridae species, which was previously scarce for the Western Cape, and this has directly contributed to an improvement in the accuracy of local species identification.
- ItemOpen AccessDNA barcoding of forensically important flies in the Western Cape(2016) Cooke, Tenielle Monique; Heyns, Marise; Heathfield, LauraOne of the central applications of forensic entomology is the determination of the post mortem interval (PMI) from arthropod evidence associated with a corpse. Estimations of the PMI are based on succession and developmental patterns of specific species that visit the body. As first colonisers, Calliphoridae (blow flies) are often used by forensic entomologists to determine the PMI however, developmental rates of visiting fauna differ substantially which makes correct species identification vital. Traditional methods of identification which assign species based on keys that capitalise on morphological differences are insufficient for closely related species, especially during immature stages of the lifecycle or when the specimen is damaged. Molecular identification such as DNA barcoding has therefore become a popular method of identifying species. DNA barcoding characterises species by sequencing and analysing specific regions in the genome. This technique has been used to characterise species in various countries including parts of South Africa. Its application has also been demonstrated in a forensic setting but data for the Western Cape is minimal. This study therefore aimed to assess the utility of DNA barcoding for species level determination of four blow fly species common to the Western Cape of South Africa (Chrysomya chloropyga, Chrysomya albiceps, Chrysomya marginalis, and Lucilia sericata) as well as its ability to identify immature specimens. Ten adult specimens from each species were morphologically and molecularly identified using microscopy and DNA barcoding respectively. The standard DNA barcode, cytochrome c oxidase subunit I (COI) and a secondary marker, the second internal transcribed spacer (ITS2) were analysed. Phylogenetic analyses for both barcodes showed high interspecific divergence values which are desirable for species level differentiation by DNA barcoding. COI sequences from adult flies were also submitted and searched against BOLD for identification and only genus level identity could be achieved, indicating that, COI alone may be insufficient to discriminate between closely related species. DNA sequences from the adult specimens were then used as reference sequences for identification of seven unknown immature specimen using DNA barcoding of both COI and ITS2. Sequence similarity was assessed and identity was assigned based on >98% similarity scores, and all immatures were successfully identified. The use of more than one DNA marker to complement morphological data ensures higher confidence of species level identification. This method provides a reliable and consistent tool for entomologists to use for species identification which results in higher levels of accuracy in PMI estimations.
- ItemOpen AccessEntomological examination of the relationship between ante-mortem and post-mortem amitriptyline concentrations in insects(2016) Sanyanga, Taremekedzwa; Heyns, Marise; Mole, Calvin GeraldWhen the death of an individual has occurred, the body of the deceased is not always discovered immediately and at times the body may be discovered after a long period of time. The consequence of discovering a body after a long period of time is that the body maybe found severely decomposed or skeletonized. As a result no viable blood, urine or tissue samples may exist that can be collected and utilized in toxicological analyses. Entomotoxicology offers a supplementary method to detect and analyse the presence of drugs post-mortem, especially in cases where viable toxicological specimens such as human tissue cannot be obtained. In South Africa and globally, standardised methodology is required to perform entomological examinations accurately, however due to the large variation of experimental set-up no such standardised methods yet exist. The main aim of the research was to analyse the effect of Amitriptyline on the development and growth rate of forensically important blow flies, and to investigate the potential in using blow fly larvae of the Western Cape, South Africa in forensic entomotoxicological analyses and future implementation. To achieve this blow fly species C. chloropyga and L. sericata were reared on homogenised pig liver containing 1000 mg/kg Amitriptyline until emergence of imago. The duration of time taken by the blow fly larvae species to reach 1 st , 2 nd , 3 rd , pupae and imago growth stages in the presence and absence of Amitriptyline was noted. The presence of drugs in larvae was investigated using high-pressure liquid chromatography coupled with dual mass spectrometry (HPLC/MS-MS). Amitriptyline was detected in all experimental larvae samples and was found to delay pupation by at least 26 hours and imago emergence by at least 72 hours. Amitriptyline however showed no distinct effect on C. chloropyga length and mass but was associated with a smaller length and mass in L. sericata compared to controls. Results indicate that entomotoxicology can be of use for qualitative analysis for the presence of Amitriptyline in forensic cases. Results also highlight the unpredictability of research using biological specimens.
- ItemOpen AccessEvaluating the role of DNA evidence in sexual offence cases in Zambia between 2007 and 2014(2017) Makasa, Innocent; Heathfield, LauraZambia has reported high incidences of sexual abuse against women and children in recent years. Zambian law categorises sexual offences into; rape, defilement, incest and others, with defilement constituting the majority of the cases (>89%). Between 2010 and 2012, only <39% of defilement cases were taken to court, and convictions were achieved in only 13% of the cases reported to the police. Literature was reviewed to determine factors which contributed towards the resolution of criminal cases, and it was found that DNA evidence was prominent in resolving crimes, specifically as an identification tool in sexual offences. Currently there is no empirical evidence describing how DNA evidence has been used in resolving sexual crimes in Zambia. The causes of low prosecution and conviction rates have also not been investigated. A retrospective study was therefore conducted to evaluate the role of DNA evidence in sexual offence cases in Zambia, reported to eight major police stations in Lusaka between 2007 to 2014 (n=1154). Sexual offence cases comprised rape (n=74, 6.4%), defilement of a child under the age of sixteen years (n=1028; 89.1%), incest (n=7; 0.6%) and others (n=45; 3.9%). Only 14 (0.1%) of the cases had forensic samples collected in the form of a vaginal swab for the sole purpose of determining the presence of semen. In all cases where a suspect was identified (60%), identification was based on the witness/victim testimonies, and in no case was forensic DNA evidence used to assist in identification or corroborate the testimonies. Overall, 28.1% cases were taken to court and the conviction rate was 12.4%. If no injuries were observed on a victim aged between 0 - 5 years, the case was not taken to court. It was also observed that the younger the victim, the more likely the accused was not identified (p < 0.001), victims did not know the date of occurrence (p < 0.001), and the case was closed due to insufficient evidence. These findings support the use of employing forensic DNA evidence in sexual offence cases to aid the identification of suspects, either in the absence of witness/victim testimonies or alongside as corroborative evidence, which is hypothesised to increase the number of cases prosecuted in Zambia. At the time of this study there was no standardised protocol for the forensic investigations of sexual offences in Zambia, which to some extent, led to numerous missing data. Development and use of the national protocol and use of a validated sexual assault evidence collection kit may help mitigate the deficiencies and inconsistencies witnessed during this study.
- ItemOpen AccessThe evaluation of tests for the identification of semen(2016) Curry, Lyle; Heathfield, LauraThe identification of bodily fluids for forensic purposes is typically classified as either presumptive or confirmatory. Presumptive tests (PT) are conducted first to screen for certain compounds which are relatively specific to particular fluids. Confirmatory tests are used to confirm the identity of a body fluid. Semen is one of the most common bodily fluids encountered in sexual assault cases and contains high concentrations of the acid phosphatase (AP) enzyme. The brentamine FB reagent reacts with the AP that is present in semen, and turns purple. If the colour change is observed within a specific time threshold, it is considered presumptively positive for semen. Cut-off time varies considerably between forensic laboratories, but in South Africa, the cut-off time is defined as 65 seconds. Additionally, semen may be considered to be from human origin if it reacts within 50 seconds. These cut off times have been arbitrarily defined, and there is little research in a local context to substantiate or inform the threshold time for the brentamine FB test for semen. Therefore this study assessed the sensitivity, specificity and kinetics of the brentamine FB test on semen from South African male volunteers (n=15), canines (n=2) and various fruit extracts and compared these results to purified human AP. Each semen sample was subjected to the PT in an indirect and direct method, and these tests were performed both on fresh and aged samples. The majority of fruit extracts yielded a distinctly different colour change compared to the purple that was produced from semen except for mushroom which also turned purple. Absorbance spectroscopy was used to determine the rate of the reaction at 525 nm. There were no significant differences between the rate of reaction for fresh and aged samples using both direct and indirect testing.
- ItemOpen AccessFirearm fatalities examined at Salt River Medico-Legal Laboratory in 2009 and their investigative outcome by 2014(2016) Wichers, Ansie; Liebenberg, Linda; Heyns, MariseSouth Africa has a very long history of gun violence, particularly politically motivated. The politically motivated gun violence did subside after 1994, however there was an increase in criminal gun violence. In 2004 Dr Liebenberg from the University of Cape Town conducted a study on the victimology and investigative outcomes of firearm deaths of 1999 in the Salt River Medico - Legal Laboratory drainage area. There were some compelling results, including a remarkably low conviction rate of 7.21%. In 2000 new legislation was enacted, which is the Firearms Control Act (1) of 2000 and from 2001 to 2005 there was a 13.6% decrease in firearm homicides which was consistent after the introduction of the new act, likely due to the decrease in the number of firearms in circulation. Because of the changes in firearm legislation and reported crime rates, it was decided to conduct a follow - up study one decade later, looking at the investigative outcomes of firearm deaths to see whether the decreased contribution of firearms in homicides and crime made an impact on the investigative and judicial process of the Salt River Medico - Legal Laboratory cases. In 2009 there were 281 firearm deaths investigated at Salt River Medico - Legal Laboratory as opposed to 532 in 1999. In 1999, 89.29% of firearm deaths were due to homicide as opposed to 86.12% in 2009. In 1999 the majority of firearm homicide victims were Black and Coloured males between the ages of 21 and 30 years, this is similar to what is seen in 2009, however there were fewer Coloured victims in 2009. In both years homicides occurred more often on weekends, at night time. In 1999 there were peaks in May and then from October through to December. In 2009 however, the peaks were in March, May and August. One might thin k that with such a large decrease in the number of firearm deaths (not considering other crime trends), the criminal justice system might have fewer cases to investigate and prosecute and that the investigative outcomes (particularly conviction rate) of th ese cases might improve. Even though there was a significant drop in the number of firearm deaths in 2009, there has been no improvement in the conviction rate, with 2009 having a rate of 5.69%. The number of cases still being investigated was also similar at 104 cases (37.01%) for 2009 versus 182 cases (34.54%) for 1999. In 2009 only 58 (20.64%) cases completed the judicial process by 2014, which includes the 16 cases (5.69%) that ended in a guilty verdict, 18 (6.41%) cases where a suspect was acquitted (not guilty) and also 24 (8.54%) cases that were withdrawn in court. Of the 281 cases for 2009, 10 (3.56%) were still in court, which was significantly less than the 59 (11.20%) cases in 1999. From 2009 there were 87 cases that reached an impasse (30.96%) by 2014, as opposed to the 114 (21.63%) cases from 1999 by 2004, which is a statistically significant difference.
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