In this review, animal related injuries occurred in 8.3% of all trauma admissions, a figure which is significantly higher than that reported by Moini et al in Iran and Nogalski et al in Poland. These differences in the rate of animal related injuries reflect differences in risk factors for animal related injuries between the study settings. The high figure of animal related injuries in this study may be due to the large number of patients with mild injuries which needed only ambulatory treatment and discharged.
The rate of the animal related injuries in the present study may be underestimated due to unreported patients, patients who died at scene or who did not reach our hospital because of treatment of minor injuries in private hospitals. A better picture of the magnitude of animal related injuries in our setting requires comprehensive data including police records, hospital admissions, and mortuary records. Better data could support useful policy guidance and help abate these injuries and their related morbidity and mortality.
In agreement with other studies [11, 18, 20], animal related injuries in our series were found to be most common in the third decade of life. High occurrences of animal related injuries among this age group have been attributed to a wide range of activities engaged in by this class of people. They represent the active group that partakes in high risk-taking activities such as farming, fishing, hunting, butchers, zoo and circus workers. The fact that this group represents economically productive age-group demands an urgent public policy response.
In our study, males were more affected than females, a finding which is in agreement with other studies [11, 18, 20, 21]. Male predominance in the present study probably reflects the greater exposure of males to outdoor activities such as farming, fishing and hunting. Identification of risk taking behavior among trauma patients has potential significance for the prevention of injuries.
The majority of patients in this study came from the rural areas located a considerable distance from the study area. This is in contrast to Moini et al who reported that animal related injuries affected both rural and urban dwellers. Farmers in rural areas are at high risk of being attacked by either wild, domestic, aquatic animals or snakes.
Previous studies conducted in the United States of America reveal that animals are one of the main causes of injuries in the farming industry [22, 23], which is similar to what was found in our series. This observation is at variant with Moini et al who reported that animal-related injuries were more common in house wives than farmers. The finding that more than eighty percent of victims of this form of trauma had no definable source of private or governmental health care insurance at the time of their injury calls for urgent public policy response.
The prehospital care of trauma patient has been reported to be the most important factor in determining the ultimate outcome after the injury . None of our patients had pre-hospital care; as a result the majority of them were brought in by relatives, Good Samaritan and police who are not trained on how to take care of these patients during transportation. The lack of advanced pre-hospital care and ineffective ambulance system for transportation of patients to hospitals are a major challenges in providing care for trauma patients in our environment and have contributed significantly to poor outcome of these patients.
Late presentation following injury is a common phenomenon in most developing countries including ours and is usually associated with increased rate of complications . The majority of our patients presented early within 24 hours of their injuries. This finding is in agreement with other studies [18, 25]. Early presentation in our study reflects the low complication rate in our patients.
In our study, dog bite was the most common cause of injuries and commonly affected children more than adult. This finding is in agreement with several studies that indicated dogs as the primary animal species implicated in animal related injuries ranging from 63-80% , but contrary to other studies which reported that equestrian traumas are common [27, 28]. Higher dog attacks in children are thought to be attributable to their size and the proximity of their face to the dogs’ mouth, and these attacks are generally related to the children’s interaction with the dog, possibly provoking the attack .
Given the proximity of our northwestern Tanzania hospital to Lake Victoria, Lake Tanganyika, and the Serengeti National Park, one would expect large number of injuries resulting from aquatic and wild animals. The low rate of injuries from aquatic and wild animals in our study can be explained by the fact that the majority of patients sustaining these severe injuries may have died before reaching the Accident and Emergency department. These animals can produce severe injuries by grasping victims with their powerful jaws and dragging them underwater, where they roll while crushing their prey .
In keeping with other studies [30, 31], the majority of injuries in the present study were in the lower and upper limbs. Attempts at using, the foot and hand to avoid animal bite may be the possible reason for these parts being affected more. The other thought is that animals may be at ease to attack moving body parts [14, 15, 31].
The type of wounds in injuries resulting from animal attack can range from minor bruises to more extensive injuries like punctured wounds, avulsions, amputations and separation of a pedunculated flap [18, 32]. In this study, open wounds such as bruises, abrasions, lacerations, punctured, avulsion, crush wounds etc and fractures were the most common type of injuries sustained. Limb amputation was reported in only 2.2% of cases mainly due to large wild and aquatic animals. Similar observation was reported previously by Chalya et al at the same institution.
It has been estimated that about 60% of animal attacks lead to such mild injuries that the ambulatory treatment is sufficient, or the injured do not call for medical help at all [22, 33]. The majority of patients in our series sustained mild injuries which is comparable with other studies [18, 22]. The large number of patients with mild injuries in this study may be responsible for the low rate of hospitalization and complications among these patients.
The principles of management of wounds resulting from animal attacks include cleaning and debriding the wound, consideration of prophylactic antibiotics, treatment of infectious complications when they develop and appropriate use of tetanus vaccination [17, 18, 32]. Whereas minor wounds are usually treated conservatively with prophylactic antibiotics, analgesics, tetanus toxoid and cleaning of wounds with normal saline and apply dressing, extensive wounds require operative procedures mainly debridement and primary or delayed primary closure.
In our study, the vast majority of hospitalized patients were treated surgically and surgical wound debridement with either primary or delayed closure was the most frequent surgical procedure performed.
In this study, wound infection was the most common complication and majority of patients had polymicrobial bacterial profile. Staphylococcus aureus was the most common organism isolated. Similar observation was also noted previously at the same study area by Chalya et al reflecting no change of bacterial profile in this region.
The current study had a mortality rate of 10.2%, which is higher than that reported by others . High mortality rate in our study was recorded in patients with severe injuries, severe head injury, tetanus and shock on admission.
The length of hospital stay (LOS) has been reported to be an important measure of morbidity among trauma patients. Prolonged hospitalization is associated with an unacceptable burden on resources for health and undermines the productive capacity of the population through time lost during hospitalization and disability. Our figures for the overall median LOS in the present study were higher than that reported by others [11, 20, 31]. Patients who had severe injuries, long bone fractures and those with hemiplegia secondary to spinal injuries stayed longer in the hospital. However, due to the poor socio-economic conditions in Tanzania, the duration of inpatient stay for our patients may be longer than expected.
Generally, the overall outcome of our patients was good as more than ninety percent of patients (survivors) were discharged well without permanent disabilities.
Self discharge by patient against medical advice is a recognized problem in our setting and this is rampant, especially amongst trauma patients . Similarly, poor follow up visits after discharge from hospitals remain a cause for concern. These issues are often the results of poverty, long distance from the hospitals and ignorance. Delayed presentation, inadequate ICU space, discharge against medical advice, and the large number of loss to follow up were the major limitations of this study. Another potential limitation was that the analyzed group of patients was treated at a single medical centre. For that reason, the results may not be adequate for the whole population in this part of Tanzania. However, despite these limitations, the study has provided local data that can be utilized by health care providers to plan for preventive strategies as well as establishment of management guidelines for patients with animal related injuries. The study also provides a comparable data to the other parts of the world in the field of animal related injuries. The challenges identified in the management of these patients in our setting need to be addressed, in order to deliver optimal trauma care for the victims of animal related injuries.