Abstract
Introduction:
Bites are an important contributor to traumatic injury worldwide. In low- and middle-income countries, data regarding bite injuries outside of rabies is limited. Therefore, we sought to describe the injury characteristics and outcomes of bites in Lilongwe, Malawi, and determine risk factors for animals and human bites.
Methods:
We performed a retrospective analysis of the Kamuzu Central Hospital trauma registry from 2008–2018. We performed Bivariate analyses comparing bite to non-bite trauma and human to animal bites. Multivariable Poisson regression modeling then estimated risk factors for bites.
Results:
A total of 124,394 patients were captured by the registry, of which 3,680 (3%) had a bite injury mechanism. Human bites accounted for 14.5% of bite injuries, and animals represented the remaining 85.5%. In rare cases, animal bite victims had serious complications, such as amputation (n = 6, 0.2%), orthopedic procedures (n = 5, 0.2%), and death (n = 7, 0.2%). Risk factors for an animal bite included being on a farm, field, or lake and being at home, whereas risk factors for a human bite included alcohol use and being at home.
Conclusion:
Animal bite injuries in Malawi can confer a risk of serious complications, such as amputation and, in rare cases, death. Alcohol-associated, in-home interpersonal violence is a significant risk factor for human bite injuries. Further studies are needed to identify risk factors for complications and mortality.
Keywords: Animal bites, human bites
Introduction
Animal and human bite wounds represent a significant global health issue and contribute to a substantial burden of traumatic injuries worldwide [1]. The vast majority of bite injuries are caused by dogs and, to a lesser extent, cats, monkeys, snakes, and humans [1,2]. Since human-animal contact is a daily occurrence for many people in various settings, from farm and feral animals to pets, it is not surprising that bite injuries are caused by a wide variety of domestic and wild animals. One of the most concerning sequela, particularly of dog bites, is rabies. It predominately affects Asia and Africa, with an estimated 56,000 deaths each year, representing 96% of the global mortality from rabies [3].
Human bites occur are due to interpersonal violence and classified as either clenched fist injuries or occlusive bites. Clenched-fist injuries or fight bites are the most common and have greater clinical significance [4]. They occur as the closed fist strikes another individual’s teeth with sufficient force to create a small wound. The injury usually occurs over the dorsal surface of the third and fourth metacarpophalangeal or proximal interphalangeal joints of the dominant hand and most often in men. Occlusive bites occur in equal frequency between men and women and happen when there is sufficient force to break the skin [5]. Most of these wounds are minor injuries and go unreported, and patients often do not seek or require medical attention. Human bites are often more dangerous than animal bites due to the human oral cavity bacteria burden, making it very easy for a human bite to become infected.
In the United States, most bites are attributable to dogs. Each year, 800,000 Americans seek medical attention for dog bites: 386,000 require treatment in an emergency department [6]. It is widely recognized that data regarding bites in low- and middle-income countries (LMIC) are under-reported, and its injury characteristics are poorly delineated [7,8]. While limited data does exist regarding animal bites in the context of rabies, few studies have examined human bites in this setting, and even less have investigated bite-associated in-hospital clinical outcomes [2,7,9,10]. We, therefore, sought to describe the risk factors, characteristics, and outcomes of patients presenting with bite injuries to a tertiary trauma center in Malawi.
Patients and Methods
We conducted a retrospective analysis of the trauma surveillance registry at Kamuzu Central Hospital (KCH) in Lilongwe, Malawi. KCH is a 900-bed tertiary care hospital that serves eight districts in Malawi’s central region, with an estimated catchment population of 6 million people. The hospital contains a 24-hour emergency department, a 4-bed high dependency unit (HDU), and a 6-bed intensive care unit (ICU). The trauma registry collects pertinent demographic, clinical, and outcome data of all patients who present to KCH with a traumatic injury. While the registry does not collect the vaccination status of the animals of bitten patients, the average rabies vaccination coverage of the region ranged from 76.9% (rural) to 85.5% (urban) in 2017 [11,12].
All patients who presented to KCH with a traumatic injury from February 2008 to May 2018 were eligible for inclusion. Patients without a documented mechanism of injury (n = 2,071) or final outcome (n = 4,555) were excluded (Figure 1). We initially described the characteristics of the bite trauma cohort by conducting a bivariate analysis of patients who presented with bite injury compared to those with a non-bite injury mechanism. We repeated a bivariate analysis was then repeated using only patients with bite injuries, comparing the characteristics of those with animal vs. human bites.
Figure 1.
Study inclusion flow diagram
The clinical characteristics examined include age, gender, occupation, injury setting, anatomic location of primary injury, admission disposition, type of operative intervention if performed, length of stay, and crude, in-hospital mortality. We categorized occupation as: farmers and domestic workers (gardeners, housekeepers), industrial workers (construction workers, technicians, plumbers, mechanics), office workers (small and large business owners, salespeople), other (teachers, artists, pastors, police), and unemployed. Normally distributed continuous variables were described using the mean and standard deviation (SD) and compared using the student’s t-test. In contrast, non-normally distributed continuous variables were described using median and interquartile range (IQR) and compared using the Kruskal-Wallis rank test. We describe categorical variables as frequencies and compared using the chi-squared and fisher’s exact tests depending on cell size.
We used a modified Poisson multivariable regression model to determine factors associated with an increased risk of sustaining a bite injury [13,14]. We included patient age and gender in the regression model a priori. We included pre-hospital demographics that were statistically significant in the bivariate analysis of bite vs. non-bite injury mechanisms in the model. We used a backward elimination approach to reduce model error and increase precision. All covariates were significant and thus remained in the model.
We performed all statistical analyses using Stata 16.0 (StataCorp, College Park, TX). The Malawi National Health Services Review Committee and the University of North Carolina Institutional Review Board approved this study.
Results
Over the 10-year study period, 124,394 patients presented to KCH with traumatic injury, of which 3,680 (3%) were due to bite injuries (Table 1). There was no statistically significant difference in the age of patients that presented with and without bite injuries (median age 22 years [IQR 10–31] vs. 24 years [IQR 10–32], p = 0.06). Patients with a bite injury mechanism had a lower proportion of males than those presenting without bite injuries (n = 2,363 [64.3%] vs. 87,770 [72.8%], p < 0.001). Patients with bite injuries had a larger proportion of farmers or domestic workers (n = 820 [22.3%]), unlike the majority of patients with non-bite injuries were office workers (n = 21,404 [17.8%]). The injury setting also differed in patients presenting with bite and non-bite injuries. Bite injuries more commonly occurred at home (n = 2,429 [67.9%] vs. n = 49,801 [42.2%], p < 0.001) while non-bite trauma more commonly occurred outside the home (n = 68,334 [57.8%] vs. n = 1,148 [32.1%], p < 0.001).
Table 1.
Bivariate analysis of bite vs. non-bite trauma
| Non-Bite N = 120,714 (97%) | Bite N = 3,680 (3%) | All N = 124,394 | p | |
|---|---|---|---|---|
|
| ||||
| Age (years), median (IQR) | 24 (10–32) | 22 (10–31) | 24 (10–32) | 0.06 |
| Male, n (%) | 87,770 (72.8) | 2,363 (64.3) | 90,133 (72.5) | <0.001 |
| Alcohol use, n (%) | 7,314 (6.1) | 89 (2.4) | 7,403 (6.0) | <0.001 |
| Occupation, n (%) | ||||
| Farmer/domestic worker | 20,157 (16.8) | 820 (22.3) | 20,977 (16.9) | <0.001 |
| Industrial worker | 19,486 (16.2) | 423 (11.5) | 19,909 (16.1) | |
| Office worker | 21,404 (17.8) | 484 (13.2) | 21,888 (17.7) | |
| Other | 1,647 (1.4) | 52 (1.4) | 1,699 (1.4) | |
| Unemployed | 57,621 (47.9) | 1,895 (51.6) | 59,516 (48.0) | |
| Injury setting, n (%) | ||||
| Home | 49,801 (42.2) | 2,429 (67.9) | 52,230 (42.9) | <0.001 |
| Work/School | 12,594 (10.7) | 399 (11.2) | 12,993 (10.7) | |
| Farm/Field/Lake | 982 (0.8) | 61 (1.7) | 1,043 (0.9) | |
| Street/Public Space or event | 54,758 (46.4) | 688 (19.2) | 55,446 (45.6) | |
| Location of Injury, n (%) | ||||
| Head or face | 40,899 (34.3) | 399 (10.9) | 41,298 (33.6) | <0.001 |
| Back | 2,598 (2.2) | 42 (1.2) | 2,640 (2.2) | |
| Chest | 5,948 (5.0) | 44 (1.2) | 5,992 (4.9) | |
| Abdomen | 5,938 (5.0) | 291 (8.0) | 6,229 (5.1) | |
| Upper extremity | 36,466 (30.6) | 1,054 (28.9) | 37,520 (30.5) | |
| Lower extremity | 27,422 (23.0) | 1,820 (49.9) | 29,242 (23.8) | |
| Transferred, n (%) | 19,991 (16.6) | 423 (11.5) | 20,414 | <0.001 |
| Admission disposition, n (%) | ||||
| Treated and discharged | 101,288 (83.9) | 3,376 (91.7) | 104,664 (84.1) | <0.001 |
| Admitted to ward | 16,700 (13.8) | 297 (8.1) | 16.997 (13.7) | |
| Admitted to HDU | 458 (0.4) | 3 (0.1) | 461 (0.4) | |
| Admitted to ICU | 308 (0.3) | 1 (0.03) | 309 (0.3) | |
| Dead in casualty | 377 (0.3) | 1 (0.03) | 378 (0.3) | |
| Brought in dead | 1,578 (1.3) | 2 (0.1) | 1,580 (1.3) | |
| Underwent surgery, n (%) | 3,884 (3.5) | 37 (1.1) | 3,921 (3.4) | <0.001 |
| Type of Surgery, n (%) | ||||
| Laparotomy | 448 (0.4) | 2 (0.1) | 450 (0.4) | 0.002 |
| Tracheostomy | 138 (0.1) | 1 (0.03) | 139 (0.1) | 0.1 |
| Laceration repair/Debridement | 2,251 (1.9) | 26 (0.7) | 2,277 (1.8) | <0.001 |
| Orthopedic Procedure | 839 (0.7) | 5 (0.1) | 844 (0.7) | <0.001 |
| Amputation | 81 (0.1) | 7 (0.2) | 88 (0.1) | 0.01 |
| Length of stay (days), median (IQR) | 7 (2–17) | 3 (1–7) | 6 (2–17) | <0.001 |
| Mortality, n (%) | 2,740 (2.3) | 7 (0.2) | 2,747 (2.2) | <0.001 |
A larger proportion of bite injured victims were able to be treated and discharged from the emergency department than non-bite trauma patients (n = 3,376 [91.7%] vs. n = 101,288 [83.9%], p < 0.001) (Table 1). Of those that were admitted, very few patients with bite injuries were admitted to the high dependency or intensive care units in comparison to non-bite trauma (n = 4 [0.1%] vs. n = 766 [0.6%], p < 0.001). Fewer bite injured patients received surgical interventions (n = 37 [1.1%] vs. 3,884 [3.5%], p < 0.001). Crude, in-hospital mortality was also significantly lower for bite injured patients than non-bite trauma (n = 7 [0.2%] vs. 2,740 [2.3%], p < 0.001).
Of the 3,680 patients presenting with a bite injury mechanism that presented to KCH, 535 (14.5%) were human bites, and 3,145 (85.5%) were animal bites (Table 2). When compared to animal bites, those with human bites were older (median age 28 years [IQR 23–34] vs. 20 years [IQR 9–31], p <0.001) and more frequently consuming alcohol at the time of their bite (006E = 63 [11.8%] vs. n = 26 [0.8%], p < 0.001). Those with human bites were most frequently farmers and domestic workers (n = 148 [27.7%]) or office workers (n = 143 [26.7%]), whereas the majority of patients with animal bite injuries were unemployed (n = 1,754 [55.9%]) or farmers and domestic workers (n = 672 [21.4%]). Both human and animal bites most commonly occurred in the home (69.3% vs. 59.8%, respectively) or the street or a public place (17.8% vs. 27.4%, respectively). Most human bites were inflicted to the upper extremity (n = 238 [44.7%]) followed by the head or face (n = 213 [40.0%]). Animal bites most frequently occurred in the lower extremity (n = 1,771 [56.8%]) or upper extremity (n = 816 [26.2%]), rarely to the head or face.
Table 2.
Bivariate analysis of human vs. animal bites
| Human Bite N = 535 (14.5%) | Animal Bite N = 3,145 (85.5%) | All N = 3,680 | p | |
|---|---|---|---|---|
|
| ||||
| Age (years), median (IQR) | 28 (23–34) | 20 (9–31) | 22 (10–31) | <0.001 |
| Male, n (%) | 358 (66.9) | 2,005 (63.9) | 2,363 (64.3) | 0.2 |
| Alcohol use, n (%) | 63 (11.8) | 26 (0.8) | 89 (2.4) | <0.001 |
| Occupation, n (%) | ||||
| Farmer/domestic worker | 148 (27.7) | 672 (21.4) | 820 (22.3) | <0.001 |
| Industrial worker | 83 (15.5) | 340 (10.8) | 423 (11.5) | |
| Office worker | 143 (26.7) | 341 (10.9) | 484 (13.2) | |
| Other | 20 (3.7) | 32 (1.0) | 52 (1.4) | |
| Unemployed | 141 (26.4) | 1,754 (55.9) | 1,895 (51.6) | |
| Injury setting, n (%) | ||||
| Home | 314 (59.8) | 2,115 (69.3) | 2,429 (67.9) | <0.001 |
| Work/School | 65 (12.4) | 334 (10.9) | 399 (11.2) | |
| Farm/Field/Lake | 2 (0.4) | 59 (1.9) | 61 (1.7) | |
| Street/Public space or event | 144 (27.4) | 544 (17.8) | 688 (19.2) | |
| Location of Bite, n (%) | ||||
| Head or face | 213 (40.0) | 186 (6.0) | 399 (10.9) | <0.001 |
| Back | 4 (0.8) | 38 (1.2) | 42 (1.2) | |
| Chest | 13 (2.4) | 31 (1.0) | 44 (1.2) | |
| Abdomen | 16 (3.0) | 275 (8.8) | 291 (8.0) | |
| Upper extremity | 238 (44.7) | 816 (26.2) | 1,054 (28.9) | |
| Lower extremity | 49 (9.2) | 1,771 (56.8) | 1,820 (49.9) | |
| Transferred, n (%) | 63 (11.8) | 360 (11.5) | 423 (11.5) | 0.8 |
| Admission disposition, n (%) | ||||
| Treated and discharged | 500 (93.5) | 2,876 (91.5) | 3,376 (91.7) | 0.6 |
| Admitted to ward | 35 (6.5) | 262 (8.3) | 297 (8.1) | |
| Admitted to HDU | 0 (0) | 3 (0.1) | 3 (0.1) | |
| Admitted to ICU | 0 (0) | 1 (0.03) | 1 (0.03) | |
| Dead in casualty | 0 (0) | 1 (0.03) | 1 (0.03) | |
| Brought in dead | 0 (0) | 2 (0.1) | 2 (0.1) | |
| Underwent surgery, n (%) | 13 (2.6) | 24 (0.8) | 37 (1.1) | <0.001 |
| Type of Surgery, n (%) | ||||
| Laparotomy | 0 (0) | 2 (0.1) | 2 (0.1) | 1.0 |
| Tracheostomy | 0 (0) | 1 (0.03) | 1 (0.03) | 1.0 |
| Lac repair/ debridement | 13 (2.4) | 13 (0.4) | 26 (0.7) | <0.001 |
| Orthopedic Procedure | 0 (0) | 5 (0.2) | 5 (0.1) | 1.0 |
| Amputation | 1 (0.2) | 6 (0.2) | 7 (0.2) | 1.0 |
| Length of stay (days), median (IQR) | 6 (2–9.5) | 3 (1–6) | 3 (1–7) | 0.03 |
| Mortality, n (%) | 0 (0) | 7 (0.2) | 7 (0.2) | 0.6 |
All human bite victims were either treated and discharged (n = 500 [93.5%]) or admitted to the ward (n = 35 [6.5%]). In comparison, three (0.1%) animal bite victims required the high dependency unit, one patient (0.03%) required the intensive care unit, one (0.03%) died in the emergency department, and two (0.1%) were dead on arrival (Table 2). A higher proportion of human bite injuries required surgical intervention than animal bites (n = 13 [2.6%] vs. 24 [0.8%], p < 0.001). Thirteen (2.4%) human bite patients underwent laceration repair or debridement, but one (0.2%) also required a digit amputation. However, in addition to the 13 (0.4%) animal bite injuries that underwent laceration repair or debridement, two (0.1%) needed a laparotomy, one (0.03%) a tracheostomy, five (0.2%) underwent an orthopedic procedure like external fixation, and six (0.2%) required amputation, including 3 arm amputations, 2 leg amputations, and 1 digit amputation. In-hospital mortality was also higher for animal bite injuries compared to human bites (7 [0.2%] vs. 0 [0%], p = 0.6).
In our modified Poisson multivariable regression model assessing risk factors for animal bites, adults aged 18–44 years (RR 1.34, 95% CI 1.19–1.50) and 45–64 years (RR 1.33, 95% CI 1.12–1.58) had a higher relative risk of suffering an animal bite than children less than 18 years of age (Table 3). The highest relative risk of animal bites occurred in a farm, field, or lake (RR 5.01, 95% CI 3.83–6.55) or at home (RR 4.00, 95% CI 3.59–4.45) compared to other public spaces. When assessing risk factors for human bites, adults aged 18–44 years (RR 7.24, 95% CI 5.09–10.15) and 45–64 years (RR 3.76, 95% CI 2.33–6.06) also had a higher relative risk of a human bite than children. Alcohol use increased the relative risk of sustaining human bite (RR 1.82, 95% CI 1.40–2.38). Being at home was the most significant risk for a human bite (RR 4.38, 95% CI 3.56–5.40) compared to a public space. Additionally, small business owners and salespeople were at a higher relative risk of sustaining human bite injury than those who are unemployed (RR 1.43, 95% CI 1,10–1.86).
Table 3.
Multivariable analysis of risk factors for being bitten when stratified by animal and human bites
| Animal Bite RR (95% CI) | p-value | Human Bite RR (95% CI) | p-value | |
|---|---|---|---|---|
| Age | ||||
| < 18 years | reference | reference | ||
| 18–44 years | 1.34 (1.19–1.50) | <0.001 | 7.24 (5.09–10.15) | <0.001 |
| 45–64 years | 1.33 (1.12–1.58) | 0.001 | 3.76 (2.33–6.06) | <0.001 |
| ≥ 65 years | 0.73 (0.53–1.00) | 0.05 | 1.23 (0.38–3.97) | 0.7 |
| Gender | ||||
| Male | reference | reference | ||
| Female | 1.11 (1.03–1.20) | 0.01 | 1.12 (0.92–1.36) | 0.3 |
| Alcohol use | 0.18 (0.12–0.26) | <0.001 | 1.82 (1.40–2.38) | <0.001 |
| Injury setting | ||||
| Public space or event | reference | reference | ||
| Home | 4.00 (3.59–4.45) | <0.001 | 4.38 (3.56–5.40) | <0.001 |
| Work/school | 2.51 (2.18–2.89) | <0.001 | 2.27 (1.67–3.08) | <0.001 |
| Farm/field/lake | 5.01 (3.83–6.55) | <0.001 | 0.99 (0.24–3.98) | 1.0 |
| Occupation | ||||
| Unemployed | reference | reference | ||
| Farmer/Domestic Worker | 1.13 (1.00–1.27) | 0.05 | 1.30 (1.00–1.69) | 0.05 |
| Industrial Worker | 0.77 (0.66–0.90) | 0.02 | 0.94 (0.69–1.29) | 0.7 |
| Office Worker | 0.73 (0.64–0.85) | <0.001 | 1.43 (1.10–1.86) | 0.01 |
| Other | 0.91 (0.63–1.30) | 0.6 | 2.81 (1.74–4.52) | <0.001 |
Discussion
Animal and human bites are a relatively common phenomenon worldwide that have the potential for significant sequelae, such as infection, disfigurement, disability, and in rare cases, fatality [15]. In this study of bite injuries presenting to a tertiary care center in Lilongwe, Malawi, we found that bites account for 3% of the trauma burden at KCH. The majority of bite injuries in our setting are due to animals and, in some cases, resulted in serious complications, such as amputation and death. In multivariable Poisson regression analysis, we demonstrated that the relative risk of animal bites was significantly increased not only while on a farm setting but also at home, raising concern for domestic animal bites. Additionally, alcohol use and being at home significantly increased the risk of sustaining a human bite concerning in-home interpersonal violence.
The burden of bite injuries is heterogeneous across LMICs. Our prevalence of 3% (2.5% animal bites and 0.5% human bites) was comparable to findings in Kenya at 3.3% but was higher than other studies performed in Nigeria and Uganda at 0.3% and 0.8%, respectively [9,16,17]. The prevalence of bites at KCH was also higher than that of the U.S., where bite-related injuries account for approximately 1% of all ED visits, 80–90% are dog, and 3% are human bites [18–20]. Our surgical management rate of bite injuries was lower than that of high-income countries (HIC) and other LMIC. For example, 30% of all animal bite injuries seen at a large referral hospital in both the U.S. and in Tanzania required operative intervention [21,22]. The low rate of mortality; however, was comparable to other settings [23].
While data from HIC have classically shown that human bite injuries, particularly to the hand, confer a higher risk of severe complications, in our study, severe complications more commonly occurred in the animal bite cohort [24]. We demonstrated that in addition to the expected risk of animal bites on farms, fields, and lakes, the home is also a setting of increased risk of animal bites. Although our dataset does not capture the type of animal bite, previous literature has found that 76–94% of all animal bite injuries in LMIC can be attributed to dogs [1,2,9]. Given that our findings suggest that in-home animals are the primary cause of animal bites, the focus of bite prevention efforts should focus on domesticated dogs rather than just strays.
Animal bite prevention strategies include community education on responsible dog ownership and increasing access to veterinary services. Responsible pet ownership encompasses the proper training, socialization, health maintenance, and restraint of dogs [25]. According to the Lilongwe Society for Protection and Care of Animals, many dog owners in Lilongwe, do not properly restrain their pets, leading to a growing population of domestic dogs freely roaming the street [26]. Furthermore, animal neglect is not uncommon in Lilongwe, as evidenced by a higher incidence of animal starvation due to lack of food or improper feeding; this increases the propensity for biting. Freely roaming dogs that have not been socialized, particularly with young children, are at a higher risk for biting [25]. Additionally, spaying and neutering is a well-accepted form of bite prevention that can decrease aggression in dogs [23]. Unfortunately, access to these services is limited due to cost, personnel, and infrastructure. While international partnerships have assisted in successfully implementing mass canine rabies vaccinations in Malawi, similar investment in increasing access to spaying and neutering services has not occurred [27].
Community education on appropriate preclinical management of dog bite injuries and increased access to post-exposure prophylaxis is needed to prevent the potentially serious complications of dog bites. The World Health Organization’s guidelines for managing animal bites include washing and disinfecting the wound with copious soap and water for fifteen minutes, applying an iodine-containing antiseptic when available, infiltration of any transdermal wound with rabies immunoglobulin, and administering a series of rabies vaccinations [28]. However, in developing countries, compliance with these guidelines is low. In Uganda, only 18.6% of patients with dog bites had flushed the wound with soap and water before presentation, and similarly, variable compliance was found in Kenya and Ethiopia [29]. Many victims of dog bites in this setting also seek traditional healers rather than allopathic medical care [30,31]. For those that do seek formal medical care, the accessibility of post-exposure rabies prophylaxis remains low in Malawi [32].
While we can presume based on existing evidence that most animal bite injuries presenting to KCH are dog bites, snakes are another common culprit in this setting. An estimated 420,000 envenomings occur in sub-Saharan Africa each year, with the total number of snake bites, including non-venomous snakes, at two to three times that estimate [33]. Snake bites can result in significant health consequences, including infection, bleeding, muscle paralysis, necrosis, amputation, and death [1]. As young, male agricultural workers are the most common victims of snake bites, the resultant physical disabilities and mortality disproportionately affect agrarian societies [34]. In sub-Saharan Africa, snake bites cause an estimated 20,000 to 32,000 deaths annually [35]. As snakebite envenoming remains a neglected tropical disease; furthermore, we need epidemiologic studies to characterize the scope of this problem in LMICs accurately. Reduction in morbidity and mortality associated with snake bites will also require community engagement in prevention strategies, such as bed nets and foot protection, Implementation of training programs for community health workers on the diagnosis and treatment of snake bites, and investment in antivenom [35,36].
We also found an association between the risk of sustaining a human bite and alcohol use, particularly at home. This finding is concerning for in-home interpersonal violence (IHPV). We have previously shown that IHPV accounts for 10% of all patients presenting to KCH with traumatic injury and that IHPV accounts for 6% of bites [37,38]. Biting as a method of assault is common in other countries in the region as well. In Nigeria and Tanzania, assault by biting most commonly occurred among people that know each other, typically neighbors or intimate partners [10,39]. While we have previously found that unemployment and alcohol use increase the risk of IHPV overall, we have now shown that alcohol use is a risk factor for suffering IPV, specifically in the form of a bite [40]. The inter-relationship between alcohol and suffering IPV is multifactorial, but it is postulated that the disinhibiting effects of alcohol reduce self-control and decrease awareness of potentially violent confrontations. Effective prevention strategies to reduce alcohol-related IPV include alcohol screening, treatment for alcohol dependency, and policy changes such as raising the cost of alcohol, decreasing its access to young people, and enforcing disorderly intoxication fines [41]. However, these interventions have primarily been tested in HICs where policies and cultural and societal attitudes towards alcohol and violence differ from many LMICs. Further research on alcohol-related IPV prevention efforts specific to LMICs is needed.
There are several limitations related to the study design. First, our data is subject to selection bias as many bite victims likely do not present to the hospital for treatment. Consequently, the prevalence of bites, particularly human bites, is probably underestimated due to the social implications of reporting. While we know anecdotally that most animal bites in our dataset are dog-related, the registry does not collect the type of animal bite. Additionally, pertinent details such as antibiotic administration and rabies status are unknown. Finally, time to presentation and hemodynamic status were missing in most participants and thus not analyzed.
Conclusion
Bite injuries as a proportion of overall injury burden are low, accounting for only 3% of overall injury burden. However, bite injuries in Malawi confer a risk of serious complications, such as amputation and, in rare cases, death. The risk of suffering a bite by a domestic animal in the home and non-domesticated animals on the farm should not be overlooked. Furthermore, the human teeth expressed in the form of a bite as a weapon for interpersonal violence is prevalent in Malawi. Further studies are needed to identify risk factors for complications and mortality.
Highlights.
Bite injuries account for 3% of the trauma burden at a Kamuzu Central Hospital, a tertiary care center in Malawi.
Animal bites in Malawi result in more serious complications than human bites, such as amputation and in rare cases, death.
In addition to the expected risk of bites on a farm, domestic animals pose an increased risk of bites in Malawi.
Alcohol-related, in-home interpersonal violence is a risk factor for suffering a human bite.
Acknowledgements
Funding: NIH Fogarty International Center Grant #D43TW009340.( Purcell and Williams)
Footnotes
Declarations of interest: none.
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