Cave Canem. Bite Mark Analysis in a Fatal Dog Pack Attack

Transcription

1 CASE REPORT Bite Mark Analysis in a Fatal Dog Pack Attack Cristoforo Pomara, MD, PhD,* Stefano D_Errico, MD,* Valerio Jarussi, DVM,Þ Emanuela Turillazzi, MD, PhD,* and Vittorio Fineschi, MD, PhD* Abstract: Deaths resulting from animal attacks are rare, and according to The Humane Society of the United States, more than 300 individuals died of dog attacks in the United States from 1979 to The case of a fatal dog-pack attack on an 83-year-old woman is presented. Wide lacerations of the scalp, several tooth puncture wounds, and bruises reproducing bite marks were recorded on the whole body. Exsanguinations due to brachial artery laceration subsequent to multiple dog bites were indicated as the main cause of death. An integrated study in association with a veterinary doctor was performed on 27 dogs of different breed (24 Cane Corso, 1 Dalmatian, 2 German Shepherds) collecting dental formula and dental casts. Dental casts were superimposed on the victim_s wound samples collected at autopsy and analyzed for compatibilityv the patterns taken from the jaws of 3 suspected dogs could be clearly adapted on the bite marks. At the end of investigation, the son of the victim indicated the 3 dogs of his own as the responsible ones and he was condemned for manslaughter. Bite marks analysis provided conclusive evidences in identifying the offending animals. The results may be important to give details about bite circumstances and predisposition of specific breeds of dogs to bite or inflict severe bites. Key Words: dog bites, bite marks analysis, forensic veterinary (Am J Forensic Med Pathol 2011;32: 50Y54) The annual incidence of dog bites is approximately 12.9 per 10,000 persons and injuries from dog bites account for approximately 1% of all emergency visits to hospital in the United States. 1Y5 Deaths resulting from animal attacks are rare and according to The Humane Society of the United States, more than 300 individuals died of dog attacks in the United States from 1979 to Most victims of fatal dog attacks are children (G1 year of age) and elderly women who were found to be the least able to protect themselves from a dog attack. 7Y24 Deaths may result from envenomation, anaphylaxis, suffocation, crushing injuries, or from hemorrhage from vascular disruption. In the United States, Pit bull-type dogs and Rottweilers were involved in more than half of dog-attack deaths (67%); they were followed by German Shepherds, Husky-type dogs, and Malamutes ( 1,6,10,12,13,18Y22,25 ); typical continental breeds related fatalities are also reported. 9,23,24 We present the case of a fatal dog-pack attack on an 83- year-old woman. An integrated study in association with a veterinary doctor was performed, collecting dental formula and Manuscript received July 31, 2009; accepted March 27, From the *Department of Forensic Pathology, University of Foggia; and Department of Medical Veterinary, Azienda Sanitaria Locale FG, Foggia, Italy. Correspondence: Vittorio Fineschi, MD, PhD, Department of Forensic Pathology, University of Foggia, Ospedale Colonnello D_Avanzo, Via degli Aviatori, 1, Foggia, Italy. [email protected]. Copyright * 2011 by Lippincott Williams & Wilkins ISSN: /11/3201Y0050 DOI: /PAF.0b013e3181edf0e2 dental casts from the jaws of suspected dogs. Dental casts were superimposed on the victim_s wound samples collected at autopsy and analyzed for compatibility and identification of the suspected dogs. CASE REPORT An 83-year-old woman was found unconscious, lying on her face on the ground, outside the farm where she lived with her sons and her 27 dogs. She was still alive when she was found by 1 of her sons who rushed her to the nearest hospital to receive medical care. The son of the old lady reported to the physicians that his mother has been victim of a dog pack attack and that she was alone with the dogs at the place and time of the attack. He also reported that dog pack was not that of his own. At the emergency department, the patient was unconscious; a diagnosis of hemorrhagic shock, requiring blood transfusions was made on the base of clinical data, showing hypothermia and laboratory findings of anemia (Red Blood Cells: ul, Hb 7.9 g/dl, Hct 23.4%). Color flow Doppler ultrasound on the ischemic left arm was performed showing the absence of radial pulse and tear of the brachial artery, which was immediately repaired by vascular surgeon. Few minutes after surgery the patient died, despite resuscitation maneuvers. A complete postmortem examination was performed a few days after death. Autopsy Findings External examination of the victim showed a welldeveloped body of an 83-year-old woman, 145 cm in length and 45 kg in weight. Wide lacerations of the scalp with exposure of the underlying galea capitis were recorded; several tooth puncture wounds, resembling stab wounds, were detected on the neck (Fig. 1, A and B). Lacerations, multiple small puncture wounds, and abrasions were observed on the whole body (upper and lower extremities, thoracic and abdominal regions, back district) (Fig. 1, C and D). Clusters of 4 to 5 superficial linear parallel abrasions between puncture wounds (single or in pairs), reproducing Bbite marks[ were recorded, especially on upper and lower extremities (Fig. 2, AYC). The wounds were documented by photographs and the distance between pairs of punctures was measured (from 4 cm to 6.5 cm) as well as between bruises. These measures were typically related to different canine dentition, and to the pattern of attack with punctures and lacerations (canines), and tissue avulsion (incisors). Then, the samples that better reproduced bite marks were collected and fixed in 10% buffered formalin. Before formalin fixation, the sectioned tissues containing patterned injuries were sutured to a synthetic rigid ring to minimize shrinkage. Internal examination showed non-lethal bite marks with extreme bleeding around soft tissues except for severely crushed left brachial biceps and left brachial artery showing a laceration about 1.5 cm long at the level of the proximal third which was surgically repaired (Fig. 2D). Exsanguinations due to brachial artery laceration subsequent to multiple dog bites were indicated as the main cause of death Am J Forensic Med Pathol & Volume 32, Number 1, March 2011

2 Am J Forensic Med Pathol & Volume 32, Number 1, March 2011 FIGURE 1. Lacerations of the scalp and several tooth puncture wounds of the neck were detected (A, B). Multiple small puncture wounds and abrasions were observed on the whole body (C, D). The victim_s own dogs were immediately suspected and investigated. An integrated study in association with a veterinary doctor was performed on 27 dogs of different breed (24 Cane Corso, 1 Dalmatian, 2 German Shepherds) usually packing free outside the farm and regularly registered and identified by means of microchip number. Measurement of all canine jaws and description of dental characteristics (missing or fractured teeth, supernumerary teeth, etc) were performed recording a dental plan (dental formula) for each dog. Then, dental plans were compared with wound samples to verify the distance between canines or to search for peculiar dental formula; it was possible to indicate just 7 dogs among 27 as strongly suspected to be responsible for the attack (Table 1). To detect the offending dogs among the 7, a dental cast of each dog was made. An impression of the teeth of each of the 7 dogs was made using dental alginate impression material following the manufacturer_s guidelines. After removing the tray out of the dogs_ mouth the hardened impression material was FIGURE 2. Bite marks were recorded on upper and lower extremities (AYC). Left brachial artery showing a laceration about 1.5 cm long at the level of proximal third, surgically repaired (D). * 2011 Lippincott Williams & Wilkins 51

3 Pomara et al Am J Forensic Med Pathol & Volume 32, Number 1, March 2011 TABLE 1. The 27 Different Breed Dogs Usually Packing Free Outside the Farm, Regularly Registered, and Identified by Means of Microchip Number Microchip Number Breed Sex Cane corso German shepherd S Dalmatian S Cane corso Cane corso S Cane corso Cane corso 9 rinsed thoroughly under running water. Plaster casts were prepared using dental calcined gypsum. The dental casts were superimposed on the victim_s wound samples collected at autopsy and analyzed for compatibility (Fig. 3A): the patterns taken from the jaws of 3 suspected dogs could be clearly adapted on the bite marks (Table 2). The position of the 6 incisors in the upper jaw of the dog identified with number showed to be identical to that of the wound on the victim_s left leg. Single puncture was due to the absence of the right upper canine. The position of the 2 canines and the position of the 6 incisors in the upper jaws of the 2 dogs identified with number and showed to be identical to that of the wound on the right leg and right gluteus (Fig. 3, BYD). Blood and 4 samples of each case were collected to eventually perform genetic investigation. TABLE 2. The 3 Suspected Dogs Identified by the Bite Marks Analysis Microchip Number Breed Sex Cane corso Cane corso Cane corso 9 At the end of investigation, the son of the victim indicated the 3 dogs of his own as the responsible ones, and he was condemned for manslaughter. DISCUSSION In the case presented, a fatal Italian Cane Corso pack attack on an 83-year-old woman is described. The Cane Corso is an ancient Italian breed, which is derived from the now extinct roman Molosser. It is a medium to large-sized dog, robust and sturdy, nevertheless elegant dog, generally owned to guard and protect people. In 1994, the ENCI accepted the Italian Cane Corso as the 14th Italian breed and in 1996 it became a recognized breed of the Federation Cynologique Internationale in the group 2, section 2.1 (Molosside breed, Mastiff type). An average of approximately 19 deaths from dog attacks was reported annually in the United States during the time period 1979 to Deaths have been reported in 49 states with Alaska reporting the highest death rate from dog attacks. The number of deaths and the death rate from dog attacks appear to be increasing. 6,26 Approximately 70% of severe attacks involved bites on the head and neck, a location for which death FIGURE 3. Plaster casts prepared using dental calcined gypsum. The dental casts were superimposed on the victim_s wound samples collected at autopsy and analyzed for compatibility (A). The position of the 6 consumed incisors in the upper jaw of the dog identified with number showed to be identical to that of the wound on the victim_s left leg. Single puncture was due to the absence of right upper canine. The position of the 2 canines and the position of the 6 incisors in the upper jaws of the 2 dogs identified with number and showed to be identical to that of the wounds on right leg and right gluteus (BYD) * 2011 Lippincott Williams & Wilkins

4 Am J Forensic Med Pathol & Volume 32, Number 1, March 2011 because of hemorrhage and shock is likely. 1,2,7,8,13,21,23 Penetrating injuries to the neck can also lead to tracheal injury with life-threatening airway compromise. Injuries to the axillary and internal carotid arteries, the spinal cord, and the skull are also reported showing the devastating effects of blunt force in vicious dog attacks. 23,27Y29 The fatal attack is characterized by repetitive, uninhibited biting, and by the dog being relatively unresponsive to attempts to terminate the attack. Unlike less serious attacks, attacks which result in death usually occur when no one but the victim is present. Causes of dog attacks include the following: (1) the dog senses that its position in the family is being threatened, most often when children and new babies are in the household, making them the most vulnerable to the attack; (2) the dog is fearfulvthe so-called fear biting is preceded by warning growls or postures, often unrecognized by children; (3) the dog senses that its territory of food is being threatened, again making unaware children most susceptible to the attack; (4) physical activity or vocalization may stimulate aggressiveness in dogs, especially when in packs; (5) a dog_s medical illness may lead to aggressive behavior (rabies, brain neoplasm, encephalitis, diabetes mellitus). 14 Dog pack attacks with human predation appear to be extremely rare accounting for 6.9% of all fatal dog attacks. 16,22,30Y32 When attacks involve more than 1 dog there may be extensive injuries to the head, face, neck, torso, and extremitiesvin these cases head and neck injuries are more frequently involved as well as abdomen and trunk, causing significant blood loss. There may be also injuries to the buttocks and limbs, particularly if dogs are hunting in a pack, as biting the hindquarters is a technique that dogs use to immobilize the prey. Nonfatal bites tend to be found on the hands, lower limbs, and face. 9,16,19 Fatalities are more likely to occur in unwitnessed attacks and result from exsanguinations from vessel trauma, air embolism from damage to veins in the neck, and/or blunt craniofacial trauma from crushing of the skull. 1,13,14 It has been suggested that in a pack situation, once an aggressive act is initiated, whether as a playful nip or a serious bite, dogs which singly taken are docile, may join in and the pack instinct escalates the attack until the victim is killed or the dogs are driven off. 30 Other factors that are believed to facilitate the initiation of attacks on humans by dogs include a possible genetic predisposition toward aggressiveness; male gender, intact reproductive status, poor health, late and inadequate training and socialization; lack of supervision, defense of territory or puppies, hunger, predatory experience, pack-dog experience, assertion of social dominance, age, size, and behavior of victims; and absence of other people in the vicinity. 22 Bite mark analysis has been shown to be useful in distinguishing between wolf and dog attacks and more recently in a number of large cat attacks. 33,34 Dog dentition is conventionally represented by a dental formula by quadrants, because dentition is bilaterally symmetrical. Thus, the canid dental formula is incisor 3/3, canines 1/1, premolars 4/4, and molars 2/3. Depending on the function of each tooth, certain types of injuries may be produced. The incisors of canids are relatively small, are used for nipping, and will produce small parallel grooves on bone. Canines are long and sharp, have small serration along one of the borders, are used to stab and tear and produce either punctures or gouges. The premolars are small, gripping teeth, which are used to hold onto prey and will produce striations on bone. The molars have small, round (bunodont) cusps and are used for crushing. 8 The canine lower dental arch is narrower and shorter than the upper and natural gaps exist between the teeth in most breeds, which may be reflected in the bite mark impressions. 15,19 Guidelines for the analysis of bite marks are important for investigation and should be respected. To standardize the analysis of bite marks, the American Board of Forensic Odontology established specific guidelines. 35 New approaches with digital technique overlaying the bite mark and patterns of a suspect animal facilitate an exact investigation. Bite mark and study casts can be compared using 3-dimensional pictures. 36Y38 The most important step was to recognize a patterned injury as a bite mark. The forensic evaluation of the fatal dog attack required an integrated approach in association with veterinary pathologists involving review of the circumstances of death, examination of death scene, and autopsy examination of the victim. 32,39 Finally, odontological analysis of bite marks, provided conclusive evidences in identifying the offending animals. 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