Galal et al ... 55 AN INITIAL STUDY ON ARTHROPOD SUCCESSION ON EXPOSED HUMAN TISSUES IN ASSIUT, EGYPT BY Lamia A. A. Galal, Saly Y. Abd-El-hameed*, Rasha A. H. Attia and Doaa A. Uonis Departments of Medical Parasitology and Forensic Medicine and Clinical Toxicology*, Faculty of Medicine, Assiut University. ABSTRACT Forensic entomology uses different stages of arthropods as an entomological evidence at death scene to estimate the postmortem interval (PMI) using either succession waves or maggot age and its develop- ment. The arthropod succession patterns are greatly affected by temperature and humidity. Their devel- opment rate also differs physiologically depending on their geographical origin. Therefore the knowledge of local fauna is very useful in forensic investigations. Data from other areas having both different envi- ronmental and faunal characteristics might provide insufficient degree of accuracy. The aim of this study is to document arthropod fauna and succession pattern in relation to decomposition stages of human left over parts, in Assiut, during spring-summer season. The experiment was performed during spring- summer season. Human left over parts from orthopedic theatre were used. Specimens were placed in a box, floored with soil and protected with scavenger-exclusion cage and placed upon the roof of Faculty of Medicine, Assiut University Campus. Inspection of the specimens was done and at each visit flying insects, larvae and crawling species were collected. Immature stages were reared in the laboratory till adult stage in order to be identified. The results of main insect groups were discussed in relation to decomposition stages. Many insect species were identified and the following orders were represented: Diptera (Calliphoridae, Sarcophagidae, and Muscidae), Coleoptera (Dermestidae) and Hymenoptera (Formicidae). Preliminary documentation of entomofauna of Assiut city (arid, urban environment) revealed that Diptera was the predominant group followed by Coleoptera. Chrysomya albiceps was the predominant species and the only Calliphora species found to colonize the human tissues. Keywords: Forensic Entomology, Insect Succession, Human Left Over Parts. INTRODUCTlON other arthropods to civil proceedings and criminal trials (Turchetto and Vanin, Forensic entomology is the science, 2004). Each group of arthropods plays a which applies knowledge of insects and given role in different stages of decompo- Mansoura J. Forensic Med. Clin. Toxicol. Vol. XVII, No. 1, Jan. 2009 Galal et al ... 56 sition of organic matter, a particular tion and environmental conditions in group being defined by the feeding hab- which a carcass occurs. Studies on carrion its of its members. The usual classifica- arthropods had been conducted in several tion of sacrosaprophagous fauna divides regions of the world to determine the spe- them into five distinct ecological groups; cies composition and succession patterns necrophages which arrive first and eat (Tabor et al., 2005). from the corpse; necrophiles, which feed on necrophages inside the corpse by pre- However, there are no published data dation or parasitism; omnivores, which on the forensically important insects in feed on the corpse and associated fauna; Assiut city, Egypt. opportunists, which use the corpse as ref- uge, source of heat, etc. and accidentals, The aim of this study is to document whose presence is due to chance. In gen- the entomofauna and its succession pat- eral, necrophages, necrophils and omni- tern in relation to the decomposition stag- vores are the most important for forensic es of human tissue during spring-summer purpose (Arnaldos et al., 2005). season. The main aim of forensic entomology MATERIAL AND METHODS is to establish the post mortem interval (PMI) or time elapsed since death by us- Site description: The study was carried ing information on the insects that visit out in Assiut city Capital of Assiut Gov- the corpse. There are two methods; first ernorate, located 375 km South to Cairo. using the developmental stages of flies Assiut Governorate is known to occur in found on corpse as they first lay eggs on the Great Desert region. Assiut city, geo- the body (Catts, 1990). A second method graphical position ranges from longitude uses the succession patterns of carrion- ar- 30o45' to 31o 27' east and from latitude 26 thropods, the type and composition of o45' to 27 o45' north (Moatamed, 2005). The fauna change in a predictable pattern as study was located in Assiut University decomposition progresses through differ- campus (31o 09' E, 27o 11' N) about 2 km ent stages (Schoenlly et al., 1996). The rate north to city centre. Elevation of the study of carrion decomposition and arthropod site was 39 meter above the sea level and succession are influenced by many factors, was 15 meter above the ground level. Co- the more important are temperature, hu- ordinates and elevation of the study site midity, rainfall and abundance of insects were taken on the day of placement with (Tantawi et al., 1996). The pattern of ar- handheld GPS unit (e-trex vista, Garmin thropod succession is specific to the loca- corp., Olathe, KS) . Mansoura J. Forensic Med. Clin. Toxicol. Vol. XVII, No. 1, Jan. 2009 Galal et al ... 57 The average maximum temperature for specimens were buried according to Is- spring and summer in Assiut are respec- lamic rules. tively 31.3oC and 37oC while the average relative humidity is for spring 28% and On-site procedure: Inspection of the 33% for summer (Moatamed, 2005). HLOP was done every day during early decomposition stages at 10 am and 6 pm Daily weather data (mean of maxi- then every two days in later stages. At mum and minimum) temperature and each visit larvae and crawling species relative humidity were acquired from were collected with a forceps. The speci- the Egyptian Meteorological Authority, mens were gently lifted to sample the Assiut station in the university cam- fauna underneath searching for post pus. feeding larvae and pupae. They were also collected up to 2 meter around the Experiments: Two experiments were experiment box. Flying insects were performed during spring-summer season. captured by an aerial net before the First experiment included two specimens carcass was moved. Collected adult flies, and the second experiment included three beetles and other insects were killed by specimens of human leftover parts ethyl acetate and placed in numbered and (HLOP). HLOP were provided from or- dated vials containing 70% alcohol until thopedic surgical theatre after tumor mass further identification (Centeno et al., excision (osteosarcoma excised from the 2002). The collected arthropod larvae and lower thigh or upper leg). Each specimen pupae were divided into two groups: the includes skin, muscles and bone. They first group was killed in hot water then were weighting about 2- 2.5kg. They were placed in vials containing 70% alcohol for exposed on soil-floored boxes protected further identification. Then the preserved by vertebrate scavenger-exclusion cage larvae were prepared according to Lee et made of stainless steal (100x 80 cm and 15 al (2004). The second group was kept alive cm height). The first experiment was ini- and reared in the laboratory by transfer- tiated on 5th May 2007 and the second on ring them into dry glass jar with small 13th May 2007. The second experiment pieces of cow liver on a layer of saw dust. lasted until skeletalization occur. Observa- Dry saw dust was added to larvae to pu- tions were recorded on the physical pate (Tantawi et al., 1996). Larvae and changes of the HLOP over time (color, adults were determined according to spe- degree of swelling fluid oozing, size of the cific keys (Greenberg, 1971; Mosallam, remaining part, ect…) every visit. After 1980; Shaumar et al., 1989; Wells et al., the end of the experiments the rest of the 1999). Mansoura J. Forensic Med. Clin. Toxicol. Vol. XVII, No. 1, Jan. 2009 Galal et al ... 58 RESULTS catched while visiting the HLOP. Calli- phoridae represented by Chrysomya albi- The first experiment results: ceps (Fig. 3) and few Sarcophagidae repre- The experiment had started on the 5th sented by Sarcophaga carnaria and May 2007, the specimens showed dryness Wolhfahrtia. It was noticed that Calliphor- of the tissues, dark brown coloration, and idae were dominating over Sarcophagi- hardness of skin and underlying tissues. dae. Hymenoptera of family Formicidae (large and small sized adults) of an uni- All along their observation for about dentified species are found wandering two weeks there were no insects seen colo- over the specimens. nizing the specimens at any stage of their development; adults, eggs or larvae. Dur- 2. Bloated stage of decomposition: It ing this period the relative humidity re- begins at 15-23 May from day 3-11 of the corded its lowest level and highest air experiment (8 days duration). temperature (Figs. 1 & 2). It begins with slight swelling of the The second experiment results: specimens, discoloration and odor of de- A total of 9 genera (Table 1) of insects cay became noticeable. Small amount of representing three orders and six families decomposition fluids were oozing beneath are found to coexist in different decompo- the specimens. Flying adults were still fre- sition stages of the human left over parts. quenting the HLOP. Sarcophagidae (Ta- (Tables 2 & 3). bles 2 & 3) had increased until to be scarce at the end of the stage, in addition to col- Decomposition stages are classified ac- ored adult flies (Table 2) and adults Musca cording to Reed (1958). domestica. Larvae of variable sizes had appeared; they were collected and reared 1. Fresh stage of decomposition: It be- in the laboratory. After 10-12 days they gins at 13-14 May from day 1-2 of the ex- emerged as adults Chrysomya albiceps, periment (one day duration). Sarcophaga carnaria, Wolhfahrtia beside two colored flies of unidentified species. This stage begins at the moment when Some larvae were detected crawling out, the specimens were excised and installed one meter away from the box.