International Medico-Legal Reporter Journal February 2021 ISSN: 2347 - 3525

Study of of a Body in Various Climatic Conditions

Shivangi Joshi3

ABSTRACT

The decomposition of a corpse can be defined as the chemical and biological degradation of a corpse into its primary respective components. The process of decomposition happens in five different stages- fresh, bloated, decay, post-decay, and dry/skeletal. The extent of decomposition is based on the noticeable changes in the corpse that can help in the estimation of post-mortem interval (PMI). Compelling advancements in the fields of forensic anthropology, entomology, taphonomy, and many more have been made in the last few years which has allowed us to have a better understanding of the decomposition process. In this review paper, post mortem changes observed in corpses exposed to different temperature and climatic conditions are discussed. Besides temperature & climatic conditions, the rate of decomposition can also be influenced by many other factors like moisture, type of soil, insect activity, presence or absence of clothing, bodily trauma, and body mass. Hence, the combined study of forensics, taphonomy, and other fields can help in drawing out inferences about how weather condition affects the decomposition of a body which will help in easier post-mortem interval estimation.

Keywords: post-mortem interval, taphonomy, decomposition, forensic anthropology

INTRODUCTION

A body undergoes several complex variations after . The decomposition of a body starts immediately from the time of death to the time when the body turns skeletonized. Body decomposition mainly comprises autolysis and , which are accompanied by various other bodily changes. Autolysis is swift and affects the tissues and cells that have a high enzyme content (such as the liver) and high water content [1]. The early stages of decomposition are marked by discoloration of the skin [2]. The absence of oxygen results in anaerobic respiration in the cells for the breakdown of adenosine triphosphate (ATP) to adenosine diphosphate (ADP) [3]. This anaerobic respiration results in the build-up of lactic acid and carbon dioxide in cells and tissues which disrupts the cell function. The enzymes present in these dead cells start self-digesting [4]. The putrefaction soon follows autolysis. The slight odor of rotting flesh and stains visible on the abdomen indicates the onset of putrefaction [5,6]. The whole body gets flooded by the bacterias i.e. Clostridium spp., Streptococci, and the Enterobacteria during the putrefactive stage [6]. These microbes destroy the cells that result in the release of several gases and body fluids, which get filled up in the cavities and causes 'bloating'. Forensic anthropology, forensic medicine, and forensic taphonomy help in investigating the sequence and types of changes occurring in decomposing bodies under varying conditions and environments. The rate and sequence of the process may vary due to multiple intrinsic (such as body mass, age, trauma) and extrinsic factors (such as environment, soil, insect activity) [5,6,7]. These factors may cause the same cadaver to exhibit various stages of decomposition at the same time [8]. The stages of decomposition taking place can also vary from one to many, depending on the geographical conditions [5,9]. Human activities also impact the decomposition rate via environment and climatic factors. An understanding of the postmortem changes is crucial for the estimation of the postmortem interval

3 M.Sc. Forensic Science, SHUATS 36 Legal Desire Media & Insights www.legaldesire.com/forensics International Medico-Legal Reporter Journal February 2021 ISSN: 2347 - 3525

(PMI). This review paper is written with a view of explaining the various changes that occur in a human once they are dead, along with the factors and the role of climate influencing them.

CHANGES IN DECOMPOSITION

The changes that develop in bodies include , , , autolysis, and putrefaction, followed by saponification, mummification, and [10].

⮚ Algor Mortis Once death has occurred, the body ceases to regulate its internal temperature and the internal temperature begins to approximate the ambient temperature [11]. The average drop of 1.5° F in body temperature per hour is noted in cool environment [5,12]. Any estimate of the post-mortem interval obtained using this technique should be limited to the very early stages of death (18 h or less) and treated with care [11]. Many scholars have devised formulae to calculate the post-mortem interval by examining the decrease in body temperature [5,12]. Most commonly the recorded temperature from the rectum and liver is used for calculation of post-mortem interval. Several factors also influence the decrease in body temperature like the size of an individual, the presence or absence of material on a corpse, and environmental conditions.

⮚ Livor Mortis It is a physical process of accumulation of blood in the blood vessels, by gravity, in the lowest part of the body. This causes the discoloration of many body parts, appearing as bright red to dark purplish [6]. Livor mortis is also referred to as post-mortem lividity or hypostasis [5,11]. The signs of livor mortis begin to appear in an hour after death [11]. They become prominent in 2-4 hours and get fixed in about 9 to 12 hours. However, it is worth noting that the timing of livor mortis is highly variable [4]. Tight-fitting clothing or continued pressure will prevent the hypostasis.

⮚ Rigor Mortis Rigor mortis is the phenomenon of muscle stiffness on a corpse because of certain chemical changes. As ATP is converted to ADP and lactic acid is produced lowering the cellular pH, locking chemical bridges are formed between actin and myosin resulting in the formation of rigor [11]. The process involves both types of muscle, i.e. voluntary and involuntary muscles. It is first evident in the facial muscles at 1 to 4 hours after death [4]. Rigor can be first detected in the face and then spreads during the next 2-3hrs to the shoulders and arms, reaching down to the trunk to involve the legs and becoming fully established by about 12hrs [13].The rigidity of muscles persists for about 24 hours or so then the body returns to a flaccid state [6,11].

⮚ Autolysis Autolysis entails cellular breakdown prompted by the chemicals produced endogenously by our body. As the heart stops pumping blood, the cells become deprived of oxygen causing them to break down and start releasing hydrolytic enzymes. This decrease in oxygen causes a decrease in intracellular pH, triggering the autolysis. The hydrolytic enzymes in the lysosomes digest carbohydrates and proteins, while fats are affected to a lesser degree [14]. The changes can be observed microscopically after 48 hours of death. As the process progresses, the external change appears in form of skin slippage. In skin slippage, the outer layer of skin, the stratum corneum begins to separate from the underlying dermis due to the production of hydrolytic enzymes from the cells at the dermal-epidermal junction in the skin [11]. Besides epidermis, hair and nails also become loose and fall off when slightly pulled.

⮚ Putrefaction The chemical processes taking place in this stage are for complex biomolecules present in our body 37 Legal Desire Media & Insights www.legaldesire.com/forensics International Medico-Legal Reporter Journal February 2021 ISSN: 2347 - 3525 that are reduced into foul-smelling gases, liquids, and simpler compounds. Most post mortem changes by putrefaction are visible macroscopically such as discoloration of skin and bloating of body parts [7]. The signs of putrefaction are visible in 4-10 days after death. The bacterias present in the gastrointestinal tract break down hemoglobin into sulfohemoglobin resulting in green abdominal staining [8]. The intestinal bacteria spread easily to different body parts through the venous system. The bacteria start hemolyzing the blood, causing the staining to appear on the chest, neck, shoulders, arms, and thighs. The veins first appear reddish-brown, then later change to green depending on the amount of formation of sulfohemoglobin. This phenomenon is known as 'marbling' [8]. Loss in structural integrity and nutrient-rich environment gives extrinsic microbes a perfect opportunity for uncontrolled growth and also to colonize in the gut, respiratory tract, and other cavities of a decomposing cadaver. The rapid production and accumulation of gas, mostly hydrogen sulfide, causes abdominal distention, swelling in the facial area and external genitalia, which ultimately causes purging of putrefactive liquids from the mouth and nostrils and referred to as ‘postmortem purging' [8,16].

⮚ Saponification Saponification is an event that occurs after death in which a body undergoes chemical changes that transform body fat into a substance called adipocere [15]. Adiopocere is a fatty substance produced as a consequence of hydrolysis and hydrogenation of fatty tissues [8]. It is waxy, and brittle in texture with yellowish off-white coloring. The process of saponification best occurs in warm and damp conditions. Adipocere formation is seen greater in bodies having a greater fat content than the emaciated ones. It can occur as early as in three weeks, but usually, it takes three months to form [9].

⮚ Mummification This is a process of natural or artificial conservation, which consists of the dehydration and exsiccation (the process of drying up) of tissues [8]. For mummification, the temperature should either be very high or very low. The low level of humidity decreases the bacterial action occurring in the corpse. The dehydrated skin and tissues undergo slow oxidative processes that make those tissues appear brown and leathery. As for the internal organs, they may be partially mummified, putrefied, with adipocere.

STAGES OF DECOMPOSITION

● Fresh Stage (0-2days)- This stage begins immediately after death. All the autolytic processes and early post-mortem changes that include algor mortis, rigor mortis, livor mortis occurs in this stage. There is no foul odor of decomposition. However, soon, blowflies (Calliphoridae) and flesh flies (Sarcophagidae) arrive and choose orifices as the site for oviposition [16].

● Bloated (2-6 days)- At this stage, the first sign of decomposition is observed. Due to the accumulation of foul-smelling gases produced by microorganisms in anaerobic putrefaction, the abdomen appears distended. Bloating and marbling can be seen together. Also, during this stage, skin changes occur, such as blisters and slippage. Skin slippage at the extremities is known as degloving [4]. The bloating spreads to the genitals and face, which makes the eyes and tongue appear protruding out [8]. The pressure built by the gases in the abdomen and other body parts causes the fluids and blood to bubble out from the nostrils and other orifices.

● Active Decay (5-11days)- The abdominal wall ruptures thereby releasing the trapped putrefactive gases. The decomposition of internal organs is slow, notably of the liver, kidney, spleen, which resist putrefaction because of their respective parenchyma cells [8]. Various compounds contribute to the potent odor of a decomposing body which attracts a range of insects and scavengers. Most 38 Legal Desire Media & Insights www.legaldesire.com/forensics International Medico-Legal Reporter Journal February 2021 ISSN: 2347 - 3525

of the soft tissue is lost because of the feeding activity of maggots. They puncture the skin and tissues, opening up the paths for other microbes present in the environment.

● Advanced Decay (10-24days)- It is the late decaying stage in which bones begin to show and only degradation-resistant tissues are left behind such as cartilage, hair. The odor of decaying flesh is weak. Dipteran species are replaced by Coleoptera species as part of a succession pattern [11].

● Skeletonization (24+ days)- In this stage, the corpse has lost most of its soft tissue and only the skeletal part remains. The process of decomposition slows down and the odor almost fades off. The skeleton may undergo various weathering processes and other changes for many years to finally fully disintegrate.

ROLE OF WEATHER ON DECOMPOSITION

Several studies have been previously conducted on the decomposition of humans remain in different weather conditions.

Cold weather The cold weather slows down the overall decay process [16]. It is observed that the cold conditions inhibit the microbial activity during the autolysis and also retard the insect activity. An extended fresh stage is observed during winter, lasting 2-4 days. The flies arriving at the corpse lay their eggs in the low temperature (6 to 13° Celsius), but at very low temperatures (6 or below 6° Celsius) the eggs laid and larvae are unable to survive thus halting the insect activity. The maggots surviving in the cavity of the chest, abdomen continues to feed and develop even in freezing weather because they produce their heat due to their large numbers [17]. In a cool environment, the foul decomposing odor remains close to the body, making it difficult to detect.

Warm weather Exposure to a warm environment accelerates the process of putrefaction [11]. This is believed so because the increase in temperature is associated with an increase in microbial activity. On a warm day, it takes only a few minutes for flies to get the whiff of the slightest decay and soon they begin to colonize the body. The fresh stage was observed on day 0 of decomposition. Bloating of the body is visible in two to seven days following death. In the event of the death being caused by a viral or bacterial infection, not only will the body temperature be higher but bacteria may be widespread throughout the cadaver and hasten postmortem decomposition [18].The body takes about two to four weeks to become nearly or completely skeletonized. On warm days the decomposition odor is dispersed in the form of a scent pool [6].

Humid/Arid The rise in humidity increase insect activity, therefore, accelerating the process of decomposition. Whereas the arid condition retards the bacterial action and dries out the soft tissue resulting in the desiccation (natural mummification) [16].

Rainfall Rainfall may flood the carcass, causing the insect and maggots to be flushed from the body, momentarily halting the feeding. However, slight rainfall alongside warm weather can rehydrate the tissues and can increase decomposition.

DISCUSSION

A cadaver is a rich source of organic content and when it undergoes decomposition, it releases lots of 39 Legal Desire Media & Insights www.legaldesire.com/forensics International Medico-Legal Reporter Journal February 2021 ISSN: 2347 - 3525 nutrients in the soil, thus affecting the ecology of the soil. The tropical climate is warm, with temperatures ranging from 20°C to 37.8°C. It is abundant in flora and fauna, therefore, has a rapid onset of decomposition. The carcass quickly starts losing mass in the active decay stage, raising the nutrient status in the soil and forming a small nutrient-rich fertile area, which escalates the insect activity.The surrounding area, later on, is covered with plant bushes, indicating increased growth. In one of the studies, a 'temperature effect' was observed in which decomposition processes occurring at the higher temperature would later occur in samples at a lower temperature. Areas situated in the temperate zone have moderate weather. The body takes less than 6 weeks in a moderate summer, and 4 months in winter, to skeletonize. The extension of decomposition stages is also observed. The fresh stage lasts for two days in the wet season (Days 0-2) whereas in the dry season it lasts only a day (Day 0-1). The continental climate has an average temperature of 21-22°C during summer accompanied by rainfall. The rainfall drops the body temperature, fluctuating the further process. Drop in the temperature causes a slight extension of the bloating stage (only a day). The highest peak of body temperature and loss of body mass was observed in the active decay stage. During low temperature (below freezing), a study reported that the sample experiences freezer burn (i.e., dehydration and oxidation), and the musculature appeared brown. The freezing temperature inhibits bacterial growth and insect activity, delaying the decay process. The soft tissues are preserved by freeze-drying, thus, exhibiting extensive preservation. Mummification and desiccation of tissues are observed in the dry climate. The large portion of the skeleton is not exposed until four to six months. Final destruction of bones occurs in about 9 months' exposure. While examining a corpse the person should also note the other details like whether the corpse recovered was buried or not. A buried corpse has a slower rate of decomposition process as compared to the corpse exposed to air this is because of its low exposure to insects and environmental changes. Similarly, infectious disease, any penetrating wounds, and clothing on the body also increases the rate of the decomposition process. Other details like rodents and carnivore animal activity in the area should also be noted as they might mutilate the body making it appear severely decomposed. One such study was conducted on pigs in the temperate southwestern Cape, South Africa. In the study, it was noted that the rate of decomposition was increased by the scavenging activity of gray mongoose (Galerella pulverulenta) in the area. Due to scavengers, early skeletonization was observed by day 14, and the isolated control remained in advanced decomposition even after 93 days [19].

CONCLUSION

Decomposition is a long process and can take years to be finally complete. The climatic conditions may influence the decomposition process but various other factors also play a major role in the process. One can also say that these factors have the potential to affect other factors. All these elements contribute to the variability in the decay rate of the human body, therefore, the postmortem interval is always estimated in a range of hours or years. Thus, expertise is required to ensure that all the factors are noted and identified before estimating the time of death in an investigation.

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