BURNING ON INVERTEBRATE COLONIZATION

Burning on Invertebrate Colonization of a Dead Body

Burning on Invertebrate Colonization of a Dead Body

Abstract

Understanding the process of corpse decomposition is basic to establishing the postmortem interval (PMI) in any death investigation even using insect evidence. The sequence of postmortem changes in soft tissues usually gives an idea of how long an individual has been dead. However, modification of the decomposition process can considerably alter the estimate of the time of death. A body after death is sometimes subject to depredation by various types of animals among which insects can have a predominant role in the breakdown of the corpse thus, accelerating the decomposition rate.(Spitz,1988)

The interference of the insect community in the decomposition process has been investigated by several experimental studies using animal models and very few contributions directly on cadavers. Several of the most frequent factors affecting PMI estimates such as temperature, burial depth and access of the body to insects are fully reviewed. On account of their activity and world wide distribution, Diptera are the insects of greatest forensic interest. The knowledge of factors inhibiting or favouring colonization and Diptera development is a necessary pre-requisite for estimating the PMI using entomological data.(Puccini,1995)

Introduction

In forensic medicine, corpse phenomena are divided into abiotic phenomena, following the end of vital activities (negative markers) and transformative phenomena following in the timeline and causing extensive modifications of morphology and structure of the corpse (positive markers). Abiotic phenomena can be immediate, i.e. evident as soon as the vital functions of the heart, lungs and brain stop (loss of consciousness, sensitivity, motion, muscle tone, absence of breathing and circulation). They can be also consequential, i.e. evident some time after death following the end of vital activities (body cooling, hypostasis, rigor mortis, dehydration and acidification). Transformative phenomena can be destructive, causing the decay of organic matter (autolysis, autodigestion and putrefaction), or conservative, i.e. causing an abnormal transformation of the corpse according to the different environmental conditions (maceration in immersed bodies, mummification in a dry environment).(Knigth,1991)

Discussion

After death most bodies undergo putrefaction that is the most important destruction process of organic matter; alternatives are a dry decomposition called mummification or a conversion to waxy substances called adipocere.(Cor,1993)

The putrefaction mechanism is therefore, a transformative and destructive phenomenon consisting essentially in the degradation and decomposition of organic matter by anaerobic bacteria (mostly habitual saprophytic hosts of the intestine) and aerobic bacteria (mostly airborne). Putrefaction is essentially due to bacterial activity throughout the body . However, during the putrefaction the aggressive intervention of exogenous and endogenous microbial factors add to those of lesser importance caused by tissue autodigestion after death (autolysis).(Spitz,1988)

The decomposition of corpses is a mixed process ranging from autolysis of individual cells by internal chemical breakdown, to tissue autolysis from liberated enzymes and from external processes introduced by bacteria and fungi from both the intestine and outer environment. The bacterial enzymatic structures cause putrid liquefaction of tissues by the breakdown of proteins, carbohydrates and lipids into their basic components (amino acids, water and carbon dioxide, fat ...