Postmortem interval (PMI)

Significant knowledge gaps exist regarding the responses of cells, tissues, and organs to organismal death. Examining the survival mechanisms influenced by metabolism and environment, this research has the potential to transform regenerative medicine, redefine legal death, and provide insights into life's physiological limits, paralleling inquiries in embryogenesis.

The National Research Council (NRC) released a report in 2009 discussing the "science" used in forensics. Specifically, the report outlined concerns regarding the state of the forensic sciences and what was needed to raise the level of rigor and reliability of these fields in a court of law. In response to this NRC document, the present paper examined several parameters used in decomposition studies that have implications for forensic entomology. Specifically, this analysis was conducted to determine the degree of repeatability in methods across studies as related to general conclusions drawn in court, entomology and forensic investigations. Forensic entomologists primarily analyze insect evidence recovered from decomposing remains to estimate a portion of the Period of Insect Activity (PIA), which encompasses the time of colonization, to infer a minimum Postmortem Interval (PMI). One method utilized by entomologists relies on succession data from published studies to generate estimates of the minimum PMI of a decedent. For this article, approximately 75 publications on arthropod succession on vertebrate carrion were reviewed for 13 criteria that are known to play instrumental roles in governing this process: 1) animal model, 2) time of actual death, 3) euthanasia method, 4) storage method, 5) storage time, 6) time of removal from storage to placement in the field, 7) time of day remains placed in the field, 8) catalog of arthropods associated with the remains over time 9) time of initial insect contact, 10) time of initial colonization (i.e., arthropod offspring located on the remains), 11) study site, 12) number of replicate carcasses and 13) months and season of study. These criteria were selected as they can directly impact arthropod colonization and succession patterns on vertebrate carrion and are easily recorded. Data indicated that such information is highly fragmented, and that key criteria necessary to repeat studies (a core principle of the scientific method) are often lacking in the published literature. As an example, among the studies included in this analysis, we could not find significant associations between arthropod taxa richness and carcass model or carcass size. In the case of carcass size, island biogeography theory predicts that larger areas/resources will hold higher diversity. We suspect that the high degree of reporting variability in taxonomic resolution and taxa-specific study focus precluded such relationships that have been reported for other disciplines of biology. Consequently, we suggest that, to date, because of these issues there has not been a comprehensive analysis (e.g., meta-analysis) to provide general inference of arthropod succession patterns on carrion to predict a minimum PMI. In order to begin standardizing such studies, we suggest that future research endeavors examining arthropod succession on carrion record detailed data for all of the suggested criteria. Doing so can result in data amassed over time for use in comprehensive and strong meta-analyses. Such results could allow for greater appreciation of variation associated with arthropod succession on carrion.

Determining the age of unidentified human skeletal remains is one of the objectives
of forensic identification. Age is estimated using the articular surface of the ilium,
pubic symphysis, acetabulum, clavicle, skull, and sternum. In November 2020,
the body of an unknown 35-year-old man was found in a black plastic bag and
transported to the Varanasi postmortem house for examination. Age can be inferred
from changes in bone morphology as people age. The age had been estimated by
the police. Bone morphology is the most accurate indicator of age, especially in
a medicolegal setting. The deceased’s age is determined to be between 40 and 45
years old after a postmortem. For this middle age group estimation of age, most
reliable morphological changes occur in acetabulum, pubic symphysis and the 4th rib.

Carrion beetles (Coleoptera, Silphidae) are a small group of Coleoptera counting less than 200 species that are worldwide spread. Silphidae are mainly carrion feeder (necrophagous species) but can also prey on other carrion inhabitants such as fly eggs or maggots and other small carrion beetles (necrophilous species). These beetles have been referred to as being part of the entomofaunal colonization of a dead body but very few studies have looked at them in forensic context. However, the use of beetles could be relevant in forensic entomology. Silphids could provide information on postmortem colonization on remains and time since death. Typically, beetles life cycles are typically longer than that of flies and may improve the postmortem interval estimation. Among their ecological preference for large vertebrate carcasses, Silphinae may have a more important value as forensic indicators than Nicrophorinae. This study focuses on two Palearctic silphine species of forensic interest: Necrodes littoralis Linnaeus and Thanatophilus sinuatus Fabricius. The beetles' life cycles were studied at two constant temperatures (18°C & 23°C) during their complete development. Each individual has been measured (4 measures of length per individual) twice a day with a geometrical micrometer during its active growth. Developmental milestones were also recorded. Three instars were identified for both species and their rate of development were also calculated for both temperatures. In addition to previous observations on Diptera conducted to calculate the minimum PMI (temperatures models), this study of the rates of development of the immature stages of Silphinae may extend the minimum PMI.

Veterinarians, particularly in the fields of veterinary forensics and veterinary epidemiology, need to be able to estimate the amount of time that has elapsed since an animal died. A reliable estimate of post-mortem interval (PMI) of the earliest cadavers found would inform veterinary services about the possible time since the index case of a disease and the possible range of the epidemic front. We pictured, in a non-targeted manner, the metabolic changes that occurred in four wild boar cadavers placed in a forested area of the NorthEastern Italy. We sampled tissue from the hind limb adductor muscles at nine different time points. The metabolic signatures of decomposing tissues were then analyzed by direct analysis in real time high resolution mass spectrometry (DART-HRMS). A non-parametric ANOVA identified a suitable number of metabolic markers that were able to describe the post-mortem changes based on PMI. In order to go beyond a simple tentative annotation, these metabolites were identified by liquid chromatography tandem high resolution mass spectrometry (LC-HRMS/MS). We were able to identify specific biomolecules that have potential for use in PMI estimation, such as dipeptides, homocarnosine, hypoxanthine, and amino acids. Next, pathway analysis confirmed the extinction of energetic metabolism and a switch towards another source of fuel for the ongoing decomposition processes. Our findings suggest that, by targeting a combination of compounds with different post-mortem stabilities, the decomposition of wild boars could be tracked by using an appropriate set of metabolites as revealed by our DART-HRMS study.

After a vertebrate dies, many of its organ systems, tissues, and cells remain functional while its body no longer works as a whole. We define this state as the ''twilight of death'' À the transition from a living body to a decomposed corpse. We claim that the study of the twilight of death is important to ethical, legal and medical science. We examined gene expression at the twilight of death in the zebrafish and mouse reaching the conclusion that apparently thousands of transcripts significantly increase in abundance from life to several hours/days postmortem relative to live controls. Transcript dynamics of different genes provided ''proof-of-principle'' that models accurately predict an individual's elapsed-time-of-death (i.e. postmortem interval). While many transcripts were associated with survival and stress compensation, others were associated with epigenetic factors, developmental control, and cancer. Future studies are needed to determine whether the high incidence of cancer in transplant recipients is due to the postmortem processes in donor organs.

In criminal and civil investigations, postmortem interval is used as evidence to help sort out circumstances at the time of human death. Many biological, chemical, and physical indicators can be used to determine the postmortem interval, but most are not accurate. Here, we sought to validate an experimental design to accurately predict the time of death by analyzing the expression of hundreds of upregulated genes in two model organisms, the zebrafish and mouse. In a previous study, the death of healthy adults was conducted under strictly controlled conditions to minimize the effects of confounding factors such as lifestyle and temperature. A total of 74,179 microarray probes were calibrated using the Gene Meter approach and the transcriptional profiles of 1,063 significantly upregulated genes were assembled into a time series spanning from life to 48 or 96 h postmortem. In this study, the experimental design involved splitting the gene profiles into training and testing datasets, ra...

Organismal death has long been considered the irreversible ending of an organism's integrated functioning as a whole. However, the persistence of functionality in organs, tissues, and cells postmortem, as seen in organ donation, raises questions about the mechanisms underlying this resilience. Recent research reveals that various factors, such as environmental conditions, metabolic activity, and inherent survival mechanisms, influence postmortem cellular functionality and transformation. These findings challenge our understanding of life and death, highlighting the potential for certain cells to grow and form new multicellular entities. This opens new avenues in biology and medicine, expanding our comprehension of life's complexity. Second, certain cells exhibit the capacity to transform into multicellular entities with novel functionalities postmortem

Individuals left to decompose in outdoor environments may be subjected to all manner of carnivore scavenging before they are recovered. This study documents scavenging patterns to determine the effect of multiple species on human-sized pig (Sus scrofa) remains in an outdoor setting. It is hypothesized that that identification of the species involved in scavenging and postmortem damage to bone will correlate with patterns in the way skeletal elements are dispersed from the original point of deposition. Furthermore, the interactions of multiple species of scavengers modifying the same remains will impact the dispersal of skeletal elements differently than in studies documenting single scavenger taxa. The research was conducted on private land in the Yosemite Valley, CA, USA. Six pigs of comparable mass to adult humans were left exposed for five weeks beginning May 22, 2012, and observed daily for the first two weeks. After skeletonization, the bones were mapped, collected, and examined for carnivore modification. Two additional pigs were placed separately and left undisturbed for approximately six weeks, after which v a thorough search of the area was undertaken to locate and map skeletal elements. Eighteen defleshed cow (Bos taurus) femora were also secured in the same outdoor environment to document scavenger gnaw marks and behavior. Six additional femora were given to domestic dogs (Canis familiaris) to document gnaw marks and behavior. Results of this study suggest that regular human interaction has an impact on carnivore behavior. During observational period of the study, carnivore activity was nonexistent. Once daily observations had ceased, within two days coyotes (Canis latrans) and wild pigs (Sus scrofa) began scavenging the remains. Coyotes and turkey vultures (Cathartes aura) scavenged the undisturbed pigs as early as two days after deposition, and complete disarticulation had occurred by the end of the six-week study. The cow femora were scavenged by turkey vultures and ravens (Corvus corax) daily regardless of human presence but were only scavenged by coyotes after daily observations had ceased. Analysis of dispersal patterns revealed that a majority of skeletal elements were found either adjacent to the original deposition site or along nearby game trails. This suggests following game trails is an effective technique for law enforcement attempting to locate remains. However, entire carcasses can be removed with minimal skeletal elements or soft tissue left behind, stressing the importance of detailed searches for small bones to establish the original site of deposition. vi

Individuals left to decompose in outdoor environments may be subjected to all manner of carnivore scavenging before they are recovered. This study documents scavenging patterns to determine the effect of multiple species on human-sized pig (Sus scrofa) remains in an outdoor setting. It is hypothesized that that identification of the species involved in scavenging and postmortem damage to bone will correlate with patterns in the way skeletal elements are dispersed from the original point of deposition. Furthermore, the interactions of multiple species of scavengers modifying the same remains will impact the dispersal of skeletal elements differently than in studies documenting single scavenger taxa.

The research was conducted on private land in the Yosemite Valley, CA, USA.
Six pigs of comparable mass to adult humans were left exposed for five weeks beginning May 22, 2012, and observed daily for the first two weeks. After skeletonization, the bones were mapped, collected, and examined for carnivore modification. Two additional pigs were placed separately and left undisturbed for approximately six weeks, after which a thorough search of the area was undertaken to locate and map skeletal elements. Eighteen defleshed cow (Bos taurus) femora were also secured in the same outdoor environment to document scavenger gnaw marks and behavior. Six additional femora were given to domestic dogs (Canis familiaris) to document gnaw marks and behavior.

Results of this study suggest that regular human interaction has an impact on carnivore behavior. During observational period of the study, carnivore activity was nonexistent. Once daily observations had ceased, within two days coyotes (Canis latrans) and wild pigs (Sus scrofa) began scavenging the remains. Coyotes and turkey vultures (Cathartes aura) scavenged the undisturbed pigs as early as two days after deposition, and complete disarticulation had occurred by the end of the six-week study. The cow femora were scavenged by turkey vultures and ravens (Corvus corax) daily regardless of human presence but were only scavenged by coyotes after daily observations had ceased.

Analysis of dispersal patterns revealed that a majority of skeletal elements were found either adjacent to the original deposition site or along nearby game trails. This suggests following game trails is an effective technique for law enforcement attempting to locate remains. However, entire carcasses can be removed with minimal skeletal elements or soft tissue left behind, stressing the importance of detailed searches for small bones to establish the original site of deposition.

The purpose of this research study was to empirically study the temporal order of events of postmortem changes in Missoula, Montana utilizing pig (Sus scrofa) cadavers as human proxies by documenting postmortem changes and rate of soft tissue decomposition of three pigs over the course of one year and 19 days. The data from this study will be compared and contrasted to studies that have occurred elsewhere. A full understanding of the postmortem changes and rate of soft tissue decomposition in this area will help forensic anthropologists better understand why the postmortem interval (PMI) may be different in western Montana than in other states or countries. The current research study reveals that previous methods for estimating the PMI using accumulated degree-days (ADD) and total body score (TBS) are not appropriate for Montana, as the climates are too disparate. Building a body of longitudinal data that documents environmentally related soft tissue decomposition or change will be a first step towards developing a decomposition sequence and time scheme that can be used to more accurately estimate the PMI in this region. In Montana a number of partially decomposed cases enter the medico-legal system each year. Thus, greater knowledge about the postmortem period will be a significant contribution to members of the medico-legal community as well as the criminal justice system. In addition, this data could be extended to similar climatic zones. Key Words [Decomposition process, avian scavenging, mummification, total body score (TBS), accumulated degree-days (ADD), postmortem interval PMI] construct my proposal and research. I know it was a lot of work, but I greatly appreciate it. My committee co-chairperson, Dr. Ralph E. Williams: for all of your support and work on my entomology aspect of my thesis. I would especially like to thank you for taking the time to identify all of samples. Your help was invaluable. My committee members, Dr. Randall Skelton and Dr. Dan Doyle: Thank you for your advice, edits, and support of this thesis. I enjoyed working with you in class and throughout this process. Tom and Janet Lloyd: Thank you for allowing me to conduct my research on your ranch. You were so accommodating. Thank you to all of my friends and family members that helped me survive the last two years. I could not have done this without you. Lastly, I would like to thank my best friend and husband of 27 years, Stocky White. I have no idea what I would do without my partner in life. You have been wonderful. I'm very proud of you for getting accepted as a Ph.D. student. We have a life full of adventures ahead of us! v

Despite an increasing literature on the decomposition of buried and exposed human remains it is important to recognise that specific microenvironments will either trigger, or delay the rate of decomposition. Recent casework in arid regions of the world has indicated a need for a more detailed understanding of the effects of burial over relatively short timescales. The decomposition of buried human remains in the coastal desert of Peru was investigated using pig cadavers (Sus scrofa) as body analogues. The project aims were to specifically examine the early phases of natural mummification and contrast the effects of direct burial in ground with burial in a tomb structure (i.e. with an air void). Temperature was logged at hourly intervals from both the surface, grave fill and core body throughout the experiment. In addition, air temperature and humidity were measured within the air void of the tomb. After two years all three pig graves were excavated, the temperature and humidity data downloaded and the pig carcasses dissected on site to evaluate condition. The results demonstrate that: (1) there were distinct differences in the nature/rate of decomposition according to burial mode; (2) after two years burial the carcasses had been subject to considerable desiccation of the outer tissues while remaining moist in the core; (3) the body had undergone putrefactive change and collapsed leading to slumping of soil within the grave fill following the curvature of the pig's back, although this was not evident from the surface; (4) there was a specific plume of body decomposition products that wicked both horizontally and also vertically from the head wounds in the sandy desert soil. These observations have widespread application for prospection techniques, investigation of clandestine burial, time since deposition and in understanding changes within the burial microenvironment under arid conditions.

The enigmatic larvae of the Old World genus Passeromyia Rodhain & Villeneuve, 1915 (Diptera: Muscidae) inhabit the nests of birds as saprophages or as haematophagous agents of myiasis among nestlings. Using light microscopy, confocal laser scanning microscopy and scanning electron microscopy, we provide the first morphological descriptions of the first, second and third instar of P. longicornis (Macquart, 1851) (Diptera: Muscidae), the first and third instar of P. indecora (Walker, 1858) (Diptera: Muscidae), and we revise the larval morphology of P. heterochaeta (Villenueve, 1915) (Diptera: Muscidae) and P. steini Pont, 1970 (Diptera: Muscidae). We provide a key to the third instar of examined species (excluding P. steini and P. veitchi Bezzi, 1928 (Diptera: Muscidae)). Examination of the cephaloskeleton revealed paired rod‐like sclerites, named ‘rami’, between the lateral arms of the intermediate sclerite in the second and third instar larva. We reveal parastomal bars fused apicall...

Three representatives of the muscid genus Muscina Robineau-Desvoidy (Diptera: Musicidae), Muscina levida (Harris), Muscina prolapsa (Harris) and Muscina stabulans (Fallén), are well known for their medical, veterinary and forensic importance. However, data in the literature provide contradictory information for the identification of third instar larvae of these species. This hinders easy species differentiation because it requires the rearing of material to adult stages in order to facilitate reliable identification. Third instar larvae of these three Muscina species were studied in detail using light and scanning electron microscopy to provide thorough redescriptions of their morphology. Existing information concerning third instar morphology, with particular reference to its value for taxonomy and identification, is revised and discussed. Emden's spiracular distance factor (SDF) is considered here as inappropriate for identification purposes in third instar larvae of Muscina s...

A method to estimate the time since death using immunohistochemistry was exposed.-With increasing postmortem interval (pmi) the stainability of antigens decreases.-This allows a rough estimation of the time since death.-In this first control study the reduced stainability of antigens can be confirmed.-For thyreoglobulin and calcitonin we received much earlier negative stainings.

This research examined differences in decomposition rate and manner of domestic pig subjects (Sus scrofa) in never frozen (control) and previously frozen (experimental) research conditions. Eight control and experimental subjects were placed in an identical outdoor research environment. Daily quantitative and qualitative measurements were collected: abdominal circumference, total body score (TBS), temperature, photographs, descriptive decomposition stages, and visual observations. Field necropsies were performed at accumulated degree days (ADD) between 50 and 300 (Celsius). Paired samples t-tests of ADD to TBS >3.0, TBS >9.5, and TBS >16.0 indicate the rate of decomposition of experimental subjects was significantly slower than controls at both TBS >3 and >9.5 (p = 0.003 and p = 0.002, respectively). A suite of qualitative indicators of predecomposition freezing is also reported. The differences between experimental and control subjects suggest previously frozen subjects should not be used in taphonomic research, as results do not accurately reflect the "normal" taphonomic condition.

Determining time since death (post-mortem interval or PMI) is an essential part of medico-legal death investigations. PMI can give investigators important information about time of death and may help answer questions about the events leading up to death. The purpose of this study was to collect decompositional data from an understudied region (Oregon), and compare multiple scoring methods that are current standards developed in regions such as Tennessee, in order to characterize the effects of regional variation on decomposition and taphonomy. Six pig heads were placed on the ground surface in a fenced enclosure and exposed to the natural winter environment of the Willamette Valley (WV) of Oregon for sixty days. Three of these pig heads underwent sharp force trauma infliction (SFT) in order to compare rate of decay with remains that have a singular SFT wound. Stage of decomposition, temperature, precipitation, and preliminary entomological data were collected throughout the sixty-day observation period. These data were used to compare Anderson and VanLaerhoven's (1996) stages of decomposition model to Megyesi et al.'s (2005) total body scoring (TBS) system in the WV; compare and contrast similar studies from different seasons within the WV; I would like to thank the professors and instructors who have supported and aided in my efforts to accomplish this project. Specifically, I would like to extend a huge thank you to the committee members for all their help in this journey over the past five years. Thank you to Dr. Daphne Gallagher, for supporting my anthropological aspirations since Day 1 of my time at the University of Oregon and always being a resource for advice. Thank you to Dr. Stephen Dueppen, for stepping in as an acting thesis advisor when nature decided to throw a curve ball in my plans and providing me with the opportunity to work in the African Archaeology Laboratory. Thank you to Dr. Frances White for providing me with the opportunity to be a part of the Primate Osteology Laboratory and for your patience and assistance with the statistical analyses used within this project. Finally, I would like to extend my deepest thanks to my adviser Dr. Jeanne McLaughlin, without whom this project would have never been a possibility. Thank you for believing in me, inspiring me, and shaping me into the student and researcher I am today. I would like to thank the University of Oregon Anthropology Department, Lane Community College, Robert D. Clark Honors College, and the McNair Scholars program for providing funding for this project. I would also like to thank the visiting observers who so kindly shared their scoring data with me. Additionally, I would like to thank members of the Primate Osteology Laboratory and Brittany Falconer for their continuous input and support of this project. I would like to thank Dutch Bros Coffee v Company for providing the caffeine that fueled not just this thesis process but also the last five years of study sessions and late nights. Last, but certainly not least, I would like to thank the friends and family that have kept me going during this process. I would specifically like to thank Ross Casebolt, Melissa McCubbins, and Christina Young both for their support in this endeavor and their encouragement to continue my education and pursue my dreams.

Comparative decomposition rates of piglet carcasses were obtained when interred in air, soil, horse manure or pig manure to test the belief that pig manure expedites soft tissue decomposition in forensic cases. Data do not support this claim. Results show initial rapid rates of decomposition variables in air, but piglets buried in soil, horse manure and pig manure caught up to the exposed piglets' decomposition rates by the end of the twelve-day experiment. Both piglet tissues and manure have low C/N ratios (<20:1) as opposed to the optimal composting C/N ratio of 30:1 to yield accelerated decomposition. Limitations of this study are addressed with suggestions for future studies with forensic relevance.

Making optimal oviposition decisions is especially important for female carrion colonizing insects whose larvae often depend on ephemeral resources. Optimal oviposition theory predicts that females should exhibit behaviors that will maximize the performance of their offspring. Oviposition can be influenced by a variety of factors, including temperature. The aim of this study was to investigate the effects of temperature on the oviposition behavior and egg load of two blow fly species native to southern Ontario: Phormia regina Meigen, and Lucilia sericata Meigen (Diptera: Calliphoridae). Using fetal pig carcasses as an oviposition substrate, we assessed the length of time until the first oviposition event, preferred oviposition sites, and the total number of eggs oviposited. For each of the two species, five different temperature treatments ranging from 15 to 35°C were used. Temperature influenced time to the first oviposition event, as well as the number of eggs deposited by L. sericata and P. regina. As temperature increased, oviposition occurred faster with more eggs deposited for these two species. Female P. regina, in particular, demonstrated a higher egg load with increasing temperature. Differences in optimal temperatures for reproduction, including egg load and oviposition, may be a mechanism driving seasonal temporal resource partitioning leading to species coexistence utilizing ephemeral resources.

In the recent past, several human decomposition facilities have been established to systematically study how the human body decomposes under different environmental conditions. However, as of today&#39;s date, India lacks such infrastructure and relies completely on animal analogues for decomposition research. A discussion regarding the establishment of a dedicated human decomposition research facility in India has been presented and its potential benefits for forensic science education and research in the long run has been argued in this article.

Recent, short-term studies on porcine and human models (albeit with few replicates) demonstrated that the succession of the microbial community of remains may be used to estimate time since death. Using a porcine model (N=6) over an extended period of time (1703 ADD, or two months), this study characterized the eukaryote community of decomposing remains. Skin microbial samples were collected from the torso of each set of remains every day during the first week, on alternate days during the second week, and once a week for the remainder of the 60day period; all collection intervals were recorded in accumulated degree days (ADD). The eukaryote community of each sample was determined using 18S ribosomal DNA (rDNA) MiSeq high throughput sequencing; data were analyzed in the Mothur pipeline (v1.39.5) and in IBM SPSS and R statistical packages. The relative abundance of eukaryote taxa across ADD/Days and an Analysis of Molecular Variance (AMOVA) indicated similarities between sequential ADD/Days, but significant differences in the eukaryote communities as broad stage 'milestones' of decomposition were reached. Fresh remains (0-57 ADD/0-2 Days; exhibiting a Total Body Score (TBS) of 0-10) were characterized by the combined presence of Saccharomycetaceae, Debaryomycetaceae, Trichosporonaceae, Rhabditida, and Trichostomatia. During bloat and active decay (87-209 ADD/3-7 Days; exhibiting TBS of 11-20), Diptera was the most abundant eukaryotic taxa. During advanced decay stage (267-448 ADD/9-15 Days; exhibiting TBS of 21-25), Rhabditida was the most dominant eukaryote. Dry/skeletal remains (734-1703 ADD/26-61 Days; TBS ≥26) were dominated by fungal families Dipodascaceae, Debaryomycetaceae, Trichosporonaceae, and Sporidiobolaceae. Using the family-level eukaryote taxonomic data for the entire study, random forest modeling explained 89.58% of the variation in ADD/Days, with a root mean square error (RMSE) of 177.55 ADD (≈6 days). Overall, these results highlight the importance of the microbial eukaryote community during the process of decomposition and in estimation of PMI.

According to the Human Microbiome Project (HMP), a healthy human body contains ten times more microbes than human cells. Microbial communities colonize different organs of the body, playing fundamental roles both in human health and disease. Despite the vast scientific knowledge of the role of microbial communities in a living body, little is known at present about microbial changes occurring after death, thus leading many authors to investigate the composition of the thanatomicrobiome and its potential applications in the forensic field. The aim of the following review is to provide a general overview of the advances of postmortem microbiology research, mainly focusing on the role of microbiological investigations carried out on internal organs and fluids. To this end, a total of 19 studies have been sistematically reviewed, each one chosen according to specific inclusion/exclusion criteria. The selected studies assess the contribution of contamination, postmortem transmigration and agonal spread to microbial isolation from dead body samples, and shed light on the role of postmortem microbiological investigations in several forensic fields, such as cause of death or PMI determination.

After the death of individuals, sequential degradative processes called autolysis and putrefaction are initiated in the tissues, processes that cause total or partial degradation, sometimes leaving remnants of tissue. Mummification is a process by which the degradative processes are slowed and, in some cases, stopped, allowing the tissue to be apparently preserved. There are two main types of mummification: natural and artificial; natural mummification is caused by conditions related to the environment in which the tissues are located. Within the artificial techniques, there is cadaveric preservation (embalming), a procedure currently used for health and scientific studies. To carry out studies of tissues in some degree of decomposition or mummified, it is necessary to submit the samples for a process called recovery and/or rehydration, by means of immersion techniques in hypotonic solutions, which facilitates the processing and subsequent analysis of the characteristics of these ti...

ABSTRACTUnderstanding the physiological processes that underpin primate performance is key if we are to assess how a primate might respond when navigating new and changing environments. Given the connection between an animal’s ability to thermoregulate and the changing demands of its thermal environment, increasing attention is being devoted to the study of thermoregulatory processes as a means to assess primate performance. Infrared thermography can be used to record the body surface temperatures of free-ranging animals. However, some uncertainty remains as to how these measurements can be used to approximate core body temperature. Here, we use data collected from wild vervet monkeys (Chlorocebus pygerythrus) to examine the relationship between infrared body surface, core body, and local climate, to determine to what extent surface temperatures reflect core body temperature. While we report a positive association between surface and core body temperature – a finding that has previo...

Taphonomic study was fi rst time conducted in Kuala Lumpur, capital city of Malaysia. In this research model, male Oryctolagus cunicullus weighed 1.8-2.6 kg each were killed by Dolethal intravenously at the ear region. In Phase 1 study, eight subjects were wrapped in a sack and cemented within a container to be compared with the other four controls at each location labelled A (ground) and B (manmade freshwater pond). Phase 2 involved duplicating set of 15 cemented samples comparable to 1 control made up to total of 32 subjects which were all put into a compact polytank containing freshwater to simulate a case study. Taphonomic changes were observed and scored using TBS system incorporating of fresh stage, early decomposition stage, advanced decomposition stage and skeletonisation stage. The ambient temperature of surroundings with 28.81C±4.21°C and 29.21°C±4.57°C (mean±S.D.) while relative humidity of air with 74.49 %±14.61% and 79.15%±16.32% (mean±S.D.) were recorded for Phase 1 and Phase 2 study respectively. Time taken for ground control exposed and wrapped carcasses to reach fi rst sign of skeletonised stage were four days and fi ve days respectively. Whilst freshwater controls reached initial skeletonised stage within one week for exposed carcass and two weeks for wrapped carcass. Within the control and cemented sample carcasses, TBS scores increased from initial stages of decomposition and become plateau after advanced decomposition. The cementing factor have superseded the wrapping factor due to its stronger physical barrier effect to slow down the decomposition more than half compared to controls based on Multiple way ANOVA test. Phase 2 study has demonstrated more accurately on the decomposition rate of the cemented samples. It showed that wrapping and cementing factors have delayed the decomposition process of the rabbit carcasses about 4 times to reach the initial stage of skeletonisation compared to the control carcasses. There was absence of insect activity within the cemented samples, hence the microorganism activity would be the only contributor to the decaying process within the cemented samples at slower rate comparing to the exposed or wrapped controls.

Carrion beetles (Coleoptera, Silphidae) are a small group of Coleoptera counting less than 200 species that are worldwide spread. Silphidae are mainly carrion feeder (necrophagous species) but can also prey on other carrion inhabitants such as fly eggs or maggots and other small carrion beetles (necrophilous species). These beetles have been referred to as being part of the entomofaunal colonization of a dead body but very few studies have looked at them in forensic context. However, the use of beetles could be relevant in forensic entomology. Silphids could provide information on postmortem colonization on remains and time since death. Typically, beetles life cycles are typically longer than that of flies and may improve the postmortem interval estimation. Among their ecological preference for large vertebrate carcasses, Silphinae may have a more important value as forensic indicators than Nicrophorinae. This study focuses on two Palearctic silphine species of forensic interest: Necrodes littoralis Linnaeus and Thanatophilus sinuatus Fabricius. The beetles' life cycles were studied at two constant temperatures (18°C & 23°C) during their complete development. Each individual has been measured (4 measures of length per individual) twice a day with a geometrical micrometer during its active growth. Developmental milestones were also recorded. Three instars were identified for both species and their rate of development were also calculated for both temperatures. In addition to previous observations on Diptera conducted to calculate the minimum PMI (temperatures models), this study of the rates of development of the immature stages of Silphinae may extend the minimum PMI.

Forensic entomology is a branch of the forensic sciences which studies insects and other arthropods (e.g. mites) in a medico-legal context. The carrion insects, mainly Diptera and Coleoptera, have particular relationships with decomposing remains which constitute a rich ephemeral resource. These insects are attracted to the cadaver that they colonize in a

Burial of remains is an important factor when one attempts to establish the post-mortem interval as it reduces, and in extreme cases, excludes oviposition by Diptera species. This in turn leads to modification of the decomposition process. The aim of this study was to record decomposition patterns of buried remains using a pig model. The pattern of decomposition was evaluated at different intervals and recorded according to existing guidelines. In order to contribute to our knowledge on decomposition in different settings, a quantifiable approach was followed. Results indicated that early stages of decomposition occurred rapidly for buried remains within 7–33 days. Between 14 and 33 days, buried pigs displayed common features associated with the early to middle stages of decomposition, such as discoloration and bloating. From 33 to 90 days advanced decomposition manifested on the remains, and pigs then reached a stage of advanced decomposition where little change was observed in the...

Given the multiple factors that may alter the rate of decomposition, one of the more difficult tasks that anthropologists and pathologists face is determining of the postmortem interval (PMI). While trauma has been widely accepted as being among those factors, recent published studies have contradicted this premise. However, major issues exist with these studies. Consequently, this study was designed to simulate a more realistic setting in an effort to settle this discrepancy in the literature. This study utilized eight porcine remains; three of which received incised wounds penetrating the thoracic cavity, three others received nonpenetrating wounds, and two were designated nontrauma controls. Measurements included evaluating the total body score (TBS) on temporal and accumulated degree days (ADD). Using a two-way repeated measures ANOVA, the results of this study found that while trauma does have an influence in the pattern of decomposition, it does not influence the rate of decomposition.

While nonhuman animal remains are often utilized in forensic research to develop methods to estimate the postmortem interval, systematic studies that directly validate animals as proxies for human decomposition are lacking. The current project compared decomposition rates among pigs, rabbits, and humans at the University of Tennessee&#39;s Anthropology Research Facility across three seasonal trials that spanned nearly 2 years. The Total Body Score (TBS) method was applied to quantify decomposition changes and calculate the postmortem interval (PMI) in accumulated degree days (ADD). Decomposition trajectories were analyzed by comparing the estimated and actual ADD for each seasonal trial and by fuzzy cluster analysis. The cluster analysis demonstrated that the rabbits formed one group while pigs and humans, although more similar to each other than either to rabbits, still showed important differences in decomposition patterns. The decomposition trends show that neither nonhuman model...

Background Decomposition timeline estimation is one of the key tools used in homicide cases to unravel the mystery behind the time of death of a victim. Decomposition timeline is the time take for a carcass to decay from time of death to skeletonization. Several events occur during this timeline. These events are controlled by certain autolytic and putrefactive factors. Other factors also play a role in the determining the rate of decomposition. However, putrefactive factors aid the eventual breakdown of a carcass. The putrefactive factors are flora activities, fauna activities, soil physicochemical properties, nature of soil, and climatic factors. This study aimed at investigating the factors that play vital role in the estimation of decomposition timeline of Sus scrofa domestica placed on the soil surface in Anambra state, Nigeria. Results Findings from the study showed that the factors that statistically (p &lt; .05) influenced the rate of decomposition includes atmospheric tempe...

One of the most important and perhaps most used applications of forensic entomology concerns the estimation of the minimum post-mortem interval (minPMI), defined as the time interval between death and the actual finding of a corpse. Some Diptera species are critical in these studies because they are the first ones capable of detecting and finding a corpse and are selectively attracted by its decomposing status. Thus, the knowledge of the micromorphology of their preimaginal stages and of their life cycles within a time frame constitutes solid indicators for estimating the minPMI. Hydrotaea capensis is a Muscidae of forensic interest usually considered as a late colonizer of corpses. It is widely distributed, living mainly in warm regions, and present in a wide variety of habitats. In this study, the H. capensis life cycle was studied at four constant temperatures, 18°, 20°, 25° and 30 °C, by recording the duration of its different developmental stages, including the length reached i...

William Seaver during data collection, analysis, and presentation. Thank you all for the advice and support. Many students assisted during data collection. Thank you to all of the undergraduate and graduate volunteers, and especially to those who came out daily during Trial 1 and the FAC summer interns of 2014 who helped with daily data collection in Trial 2. Thank you also to the entomology graduate students, especially Gary Phillips and Rob Pivar who trained me in adult fly identification and answered my endless questions. None of this research would have been possible without the generous gift of the donors to the Forensic Anthropology Center's Body Donation Program. I am forever indebted to the donors and their families. Thank you to my undergraduate mentors, Cliff and Donna Boyd, who first introduced me to anthropology and who inspired me to continue on. You are both who I want to be when I grow up. Thank you to my friends and family for putting up with me during this long and stressful process. Mom, thank you for always believing that I could do this, even (and especially) when I didn't think I could. To my sister Jenn, I couldn't have done this without you. Thank you for all the hilarious texts, all the food, and all the support! To Miriam Soto-Martinez and Shauna McNulty, I cannot express how invaluable your friendship has been over these last 13 years. I definitely would not have made it to this point without your words of wisdom and your constant emotional aid. Thank you also to Tiffany Saul for talking me through several crises of faith. And to my friend, fellow 2018 graduate and jiujitsu training partner Kelly Sauerwein-we did it! I am so glad that we could work through this process together.

Burial of remains is an important factor when one attempts to establish the post-mortem interval as it reduces, and in extreme cases, excludes oviposition by Diptera species. This in turn leads to modification of the decomposition process. The aim of this study was to record decomposition patterns of buried remains using a pig model. The pattern of decomposition was evaluated at different intervals and recorded according to existing guidelines. In order to contribute to our knowledge on decomposition in different settings, a quantifiable approach was followed. Results indicated that early stages of decomposition occurred rapidly for buried remains within 7–33 days. Between 14 and 33 days, buried pigs displayed common features associated with the early to middle stages of decomposition, such as discoloration and bloating. From 33 to 90 days advanced decomposition manifested on the remains, and pigs then reached a stage of advanced decomposition where little change was observed in the...

This thesis is a case study of winter raccoon scavenging in Maine. The data used for my analysis came from a National Institute of Justice funded project on Regional Taphonomy done by Marcella Sorg from 2007 to 2012 (Sorg, 2013). I analyzed the photographic and videographic data from one pig cadaver site and identified raccoon scavenging “events.” This term is used to describe any period of time that one or more raccoons are scavenging. These events were then analyzed to investigate possible associations between scavenging behaviors and environmental variables, although none were positively identified. I adapted a method of describing soft tissue lost via animal scavenging from the “Total Body Score” system in Megyesi et al., 2005, which was written to describe levels of decomposition. Through the analysis of the data from this site, typical raccoon behavior was established. This includes nocturnal, winter defleshing without bone modification both individually and within groups. Alt...

Decomposition studies have elucidated many different factors affecting the rate and process of decomposition. However, no study has previously investigated potential effects of posture on the decomposition process. The following study involves a research project conducted at the Anthropological Research Facility at the University of Tennessee-Knoxville to determine whether the upright posture affects the rate of decomposition. The project began on June 15, 2011, and was conducted for a period of approximately sixty days. The study included three different bodies, each placed in a different sitting position. The first was placed against a constructed, plywood wall and sat on the ground. The second body was placed in a camping chair which was nailed into the ground. The final body served as a control for the experiment, and was laid flat on the ground. The results of this study provide more information regarding the possible effects of different variables on the decomposition process and expected rate of decomposition. Furthermore, the study provides a base study for further human decomposition research in the area of posture and body position.

Background: Medico-legal case usually presents as an emergency case in any hospital. Profiling of these cases provides with evidence on the burden of the medico-legal cases and identifying ways to better manage these cases in the emergency ward of hospitals. Objective: To study the profile of medico-legal cases coming to the emergency ward of B. P. Koirala Institute of Health Sciences (BPKIHS), Dharan, Nepal. Material & Methods: We conducted a retrospective review of all medico-legal cases presenting in the emergency ward of BPKIHS from April 2015 to March 2016. The cases were profiled for socio-demography, injury and diagnosis from the medico-legal register at the emergency ward of BPKIHS. Results: Medico-legal cases comprise almost 10% of all cases at the emergency ward of BPKIHS. A total of 3,715 cases were included in this study. Half (50.0%) of the cases fell in to the category of 25-59 years. Males were almost twice (62.7%) in number, compared to females (37.3%). The top three...

While nonhuman animal remains are often utilized in forensic research to develop methods to estimate the postmortem interval, systematic studies that directly validate animals as proxies for human decomposition are lacking. The current project compared decomposition rates among pigs, rabbits, and humans at the University of Tennessee&#39;s Anthropology Research Facility across three seasonal trials that spanned nearly 2 years. The Total Body Score (TBS) method was applied to quantify decomposition changes and calculate the postmortem interval (PMI) in accumulated degree days (ADD). Decomposition trajectories were analyzed by comparing the estimated and actual ADD for each seasonal trial and by fuzzy cluster analysis. The cluster analysis demonstrated that the rabbits formed one group while pigs and humans, although more similar to each other than either to rabbits, still showed important differences in decomposition patterns. The decomposition trends show that neither nonhuman model...

While nonhuman animal remains are often utilized in forensic research to develop methods to estimate the postmortem interval, systematic studies that directly validate animals as proxies for human decomposition are lacking. The current project compared decomposition rates among pigs, rabbits, and humans at the University of Tennessee&#39;s Anthropology Research Facility across three seasonal trials that spanned nearly 2 years. The Total Body Score (TBS) method was applied to quantify decomposition changes and calculate the postmortem interval (PMI) in accumulated degree days (ADD). Decomposition trajectories were analyzed by comparing the estimated and actual ADD for each seasonal trial and by fuzzy cluster analysis. The cluster analysis demonstrated that the rabbits formed one group while pigs and humans, although more similar to each other than either to rabbits, still showed important differences in decomposition patterns. The decomposition trends show that neither nonhuman model...