eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease
Animal Bites
Updated: Jul 14, 2008
Introduction
Background
Estimates indicate that more than 5 million Americans are bitten by animals each year. Dogs and cats are involved in most of these bites. Bites from both cats and dogs require careful management, and patients may experience long-term morbidity or may even die. Cat bites have a high incidence of infection (approximately 50%), and dog bites may cause severe injury to tissues. Dog and cat populations in the United States are each estimated to exceed 50 million animals. Many households in the United States include pets, and many children are bitten by family pets.
Breeds associated with serious dog bites in children include pit bull, Rottweiler, wolf mix, Saint Bernard, German Shepherd, and Akita.
Pathophysiology
Dogs and cats have prominent canine teeth; however, great differences are observed in the structure of those teeth. Dogs have wider canines, while cats have thinner canines. Dogs are capable of exerting enormous pressure when biting, and some breeds can pierce metal plates with their teeth. In particular, the bites of large dogs can be dangerous to children. Large breeds tend to cause wounds in the head and neck areas of younger children, and their powerful jaws can penetrate the skull and destroy deep tissue. Cat bites are characterized by puncture wounds that inoculate bacteria deep into tissues.
Cats and dogs harbor a number of potentially pathogenic species of aerobic and anaerobic bacteria in the oral flora.1 Common genera include Staphylococcus, Streptococcus, Pasteurella, and Bacteroides.2 Other organisms cultured in dog bites include Capnocytophaga canimorsus and species of Eikenella, Enterobacter, Proteus, Haemophilus, and Klebsiella. Cat bites may contain Actinomyces, Fusobacterium, Peptostreptococcus, Clostridium, Wolinella, and Propionibacterium organisms. Infections should be assumed to be polymicrobial.
Frequency
United States
Estimates indicate that more than 5 million Americans are bitten by animals each year. Dog bites account for nearly 85% of the total number of animal bites, and cat bites for approximately 10%. Other animals involved in bites include rodents and other small mammals, such as ferrets and rabbits. Bites from more exotic animals (eg, snakes, lizards, monkeys, farm animals) are rare.
International
Types of animal bites can vary depending on land development and the natural flora. For example, in India, tiger bites may be encountered. In general, in North America, dogs are the agents in most animal bites.
Mortality/Morbidity
Each year, approximately 20 people die as a result of dog bites; most of these people are young children who have massive neck and head injuries resulting from the bites. The mouths in breeds of large dogs are at the height of young children's faces. Pit bulls, with powerful jaws that are capable of causing rapid and devastating damage, are responsible for nearly three fourths of all dog bite fatalities.
- Wound infection and cellulitis resulting from bacterial infections are the most common causes of morbidity.
- Bite wounds in joint spaces may be complicated by septic arthritis. Deep wounds may be complicated by osteomyelitis, and penetrating skull wounds may result in meningitis.
- Although rare, rabies can be a fatal complication of mammalian bites. The possibility of rabies should be addressed in the history.
- Puncture wounds have a higher rate of infection than lacerations. However, lacerations cause more damage to tissues.
Sex
Males are more likely than females to be bitten by dogs.3 Females are more likely than males to be bitten by cats.
Age
Animal bites are most common in children aged 5-14 years.
Clinical
History
Begin taking the history with prehospital care.
- Important details in the history include the type of animal that attacked the patient, behavior of the animal, and time of day the bite occurred. For instance, a raccoon bite in the daytime places the patient at higher risk of rabies exposure, as does an unprovoked attack.
- Document the address or location of the attack and the time of the attack (important).
- Ascertain ownership of the animal, current location of the animal, and rabies vaccination status.
- Document prehospital care (eg, wound cleansing).
- Document the patient's allergies, current medications, medical history, immunization status, and the time of the last meal.
Physical
- Focus physical examination initially on the ABCs.
- Patients with animal bites rarely require resuscitation.
- Ensure that no compromise of circulation, motor skills, or sensation is present.
- Inspect the wounds, paying careful attention to soft tissue damage, tendon exposure or injury, bone exposure, and the presence of foreign bodies.
- Limitations of the physical examination are as follows:
- Cat bites may appear innocuous but may violate joint space integrity.
- Dog bites to the head may penetrate the skull, and foreign bodies (eg, teeth, fragments of teeth) may not be detected upon examination.
Causes
Bites may be either provoked or unprovoked.
- Causes of provoked attacks
- Antagonizing an animal
- Hurting an animal
- Causes of unprovoked attacks
- Approaching the young of an animal
- Approaching an animal that is eating
- Entering the property of a territorial animal
- Nearing an animal with rabies
- Dogs are pack animals. Many instances have occurred in which individuals were mauled by packs.
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References
Brook I. Management of human and animal bite wounds: an overview. Adv Skin Wound Care. May 2005;18(4):197-203. [Medline].
Stefanopoulos PK, Tarantzopoulou AD. Facial bite wounds: management update. Int J Oral Maxillofac Surg. Jul 2005;34(5):464-72. [Medline].
Brogan TV, Bratton SL, Dowd MD, Hegenbarth MA. Severe dog bites in children. Pediatrics. Nov 1995;96(5 Pt 1):947-50. [Medline].
CID. Report of the committee on infectious diseases. In: Red Book. 24th ed. American Academy of Pediatrics; 1997:122-6.
Dire DJ. Cat bite wounds: risk factors for infection. Ann Emerg Med. Sep 1991;20(9):973-9. [Medline].
Dire DJ. Emergency management of dog and cat bite wounds. Emerg Med Clin North Am. Nov 1992;10(4):719-36. [Medline].
Dos Santos LM, Abramo TJ, Schunk JE. Dog bites. Pediatr Emerg Care. Oct 1995;11(5):313-6. [Medline].
Fleisher GR. The management of bite wounds. N Engl J Med. Jan 14 1999;340(2):138-40. [Medline].
Jones N, Khoosal M. Infected dog and cat bites. N Engl J Med. Jun 10 1999;340(23):1841; discussion 1842. [Medline].
Litwin CM. Pet-transmitted infections: diagnosis by microbiologic and immunologic methods. Pediatr Infect Dis J. Sep 2003;22(9):768-77. [Medline].
Quinlan KP, Sacks JJ. Hospitalizations for dog bite injuries. JAMA. Jan 20 1999;281(3):232-3. [Medline].
Talan DA, Citron DM, Abrahamian FM, et al. Bacteriologic analysis of infected dog and cat bites. Emergency Medicine Animal Bite Infection Study Group. N Engl J Med. Jan 14 1999;340(2):85-92. [Medline].
Further Reading
Keywords
animal bites, dog bites, cat bites, bite-related infection, mammal bites, rodent bites, ferret bites, rabbit bites, pit bull bite, pet bites, bite wound infection, cellulitis, rabies, septic arthritis, animal bites, Staphylococcus, Streptococcus, Pasteurella, Bacteroides, Capnocytophaga canimorsus, Eikenella, Enterobacter, Proteus, Haemophilus, Klebsiella, Actinomyces, Fusobacterium, Peptostreptococcus, Clostridium, Wolinella, Propionibacterium, osteomyelitis
