Biting the hand that feeds you

Fossilized remains found in the Russian province of Siberia in the 1970s are the earliest and best preserved of a pet dog, the oldest domesticated animal, with carbon dating indicating that this animal lived more than 33,000 years ago. The origin of domestic dogs likely stems from curious wolves remaining around Stone Age people and their food remnants. Over time, these early dogs evolved into the canine companions we know today.1

A post on the U.S. News & World Report website lists 10 reasons why people choose to own a pet, which include companionship, exercise, lower stress, and a means of making new friends, to name a few.2 According to a 2015 biennial National Pet Owners survey by the American Pet Products Association, almost 80 million U.S. households (65 percent) have a pet, including 78 million dogs and 86 million cats. Six percent of dogs and 27 percent of cats are taken in as strays.3

A common source of injury

Although dogs may be our closest companions, live in our homes, decrease our stress, increase our exercise, and play with our children, they are still animals with teeth. The Centers for Disease Control and Prevention (CDC) estimates that approximately 4.5 million dog bites occur annually in the U.S., and almost 20 percent of these injuries become infected. Children are more likely to receive medical attention for dog bites, with those ages five through nine most at risk for dog bites. Men are more likely than women to be bitten by a dog.4 Almost half of all dog bites involve the upper extremity.

Bite victims who seek medical attention typically are classified into two groups based upon the time of presentation. The first group presents within eight to 12 hours of the incident, with fears of contracting rabies or other infections or with concerns about permanent disfiguration of the injured body part; these wounds are often contaminated with bacteria but do not show evidence of infection. The second group seeks help more than 12 hours after the incident, most often presenting with signs and symptoms of developing infections.5

To examine the occurrence of dog bites to the upper extremity, medical records in the National Trauma Data Bank® (NTDB®) dataset for 2014 were searched using the International Classification of Diseases, Ninth Revision, Clinical Modification diagnoses codes. Specifically searched were records that contained an external cause of injury code (E-code) E906.0 (dog bite) and one of the following diagnosis codes: 880 (open wound shoulder/upper arm), 881 (open wound elbow/forearm/wrist), 882 (open wound hand), 883 (open wound fingers), 884 (open wound upper limb unspecified), 885 (traumatic amputation thumb), 886 (traumatic amputation other fingers), or 887 (traumatic amputation arm/hand). A total of 1,693 records were found, of which 1,376 contained a discharge status, including 1,315 patients discharged to home, 25 to acute care/rehab, and 30 to skilled nursing facilities; six patients died. Of these patients, 53.2 percent were male, on average 36.9 years of age, had an average hospital length of stay of 3.4 days, an intensive care unit length of stay of 5.1 days, an average injury severity score of 3.3, and were on the ventilator for an average of 4.3 days (see Figure 1).

Figure 1. Hospital discharge status

Figure 1. Hospital discharge status

Proper care for dog bites

Overall, dogs are great pets and provide their human companions with many emotional and physical health benefits. It is hard to imagine that they would bite the hand that feeds them—but it does sometimes happen, and the health effects can be significant. More than 60 different kinds of bacteria are present in a dog’s mouth, and although only a handful can cause infections, those bacteria that do are serious and can include rabies, pasteurella, methicillin-resistant staphylococcus aureus, and tetanus.4 If one sustains a dog bite, immediately wash with soap and water and seek medical attention if the wound is severe or at risk for rabies (that is, if the offending dog is unknown, appears to be sick, or has an unknown vaccination status).

Throughout the year, we will be highlighting these data through brief monthly reports published in the Bulletin. The NTDB Annual Report 2015 is available on the ACS website. In addition, information is available on our website about how to obtain NTDB data for more detailed study. If you are interested in submitting your trauma center’s data, contact Melanie L. Neal, Manager, NTDB, at


Statistical support for this article was provided by Chrystal Caden-Price, Data Analyst, NTDB.


  1. Dell’Amore C. Ancient dog skull shows early pet domestication. National Geographic News. Available at: Accessed April 1, 2016.
  2. Moeller P. 10 reasons you need a pet. U.S. News & World Report. Available at: Accessed April 4, 2016.
  3. The Humane Society of the United States. Pets by the numbers. Available at: Accessed April 2, 2016.
  4. Centers for Disease Control and Prevention. Preventing dog bites. Available at: Accessed April 1, 2016.
  5. Smith PF, Meadowcroft AM, May DB. Treating mammalian bite wounds. J Clin Pharm Ther. 2000;25(2):85-99.

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