Which Wild Animal Attacks Are Most Likely to Create Upper Limb Injuries?

December 12th, 2017

Lions, tigers, and bears might induce more fear, but the “oh my” might be saved for aquatic animals. A new study finds that those creatures produce the most common type of wild animal injury to the hand and arm.

The article in Plastic and Reconstructive Surgery states that those include stings from jellyfish, lionfish, and sea anemones, as well as other venomous aquatic animals, causing severe pain and swelling and sometimes leading to life-threatening complications. After sea creatures, which account for two-thirds of cases reported in studies included in a recent meta-analysis, were reptiles, involved in 10% of cases.

University of Wisconsin-led researchers point out that bites from animals such as beaded lizards can cause envenomation leading to systemic shock. Bites from small mammals and rodents — ferrets, skunks, and squirrels — also can cause serious complications, according to the report, and are much more common than injuries from large mammals, scorpions, centipedes, or even birds. The review, which primarily looked at hand and arm wounds, focused on injuries from wild animals and excluded pets and insects.

One difficult issue, the reviewed studies suggest, is that infections resulting from animal bites are “polymicrobial,” often caused by several different bacteria or other germs, and, therefore, have the potential to cause tissue destruction and systemic reactions.

Overall, however, study authors note that injuries from wild animals are relatively uncommon, adding, “Bites and/or envenomations from animals such as opossums, raccoons, squirrels, reptiles, rodents, fish, and other animals occur relatively infrequently but are associated with infections caused by virulent organisms that may be refractory to conventional antibiotics.”

Their update includes a quick reference to treatment of bites and stings by wild animals — both large and small.

“Existing evidence on wild animal bites is largely anecdotal,” said co-author Venkat K. Rao, MD, MBA, a plastic surgeon specializing in hand surgery. “We present a review of possible injuries and treatments.”

The authors decided to compile the information after treating an elderly man who developed a progressive infection of the hand after being bitten on the finger by an opossum. He required intravenous antibiotics in the hospital but eventually recovered.

The review identified 71 articles including 214 patients and describing less common bite and sting injuries of the upper limb, with most of the studies defined as case reports and patient series. To obtain them, the authors conducted a systematic review of PubMed and Scopus databases to identify relevant articles published between 1980 and 2016. Articles were appraised for inclusion in the study by two reviewers.

For patients who present to the emergency department and other care sites with a wild animal injury, the review offers specific recommendations for preventive antibiotics, focusing on unusual bacteria that could be present in infected wounds. The authors also suggest general treatment approaches to wild animal bites, including warm-water soaks and elevation of the affected limb. The authors warn that even a wound that seems relatively minor could result in a severe infection.

“Initial management principles for open wounds include prompt irrigation, surgical debridement of necrotic or grossly contaminated wounds, and antibiotic prophylaxis if the injury occurred on the hand and digits. Fluoroquinolones may be necessary for bites that do not improve with Gram-positive and anaerobic coverage (e.g., ampicillin/sulbactam),” they recommend. “Fish and other marine species may harbor venom, resulting in vasospasm and/or life-threatening systemic illness far more severe than the wound itself.”

The analysts also warn that wounds from uncommon animals are likely to increase in urban areas.

“The increasing prevalence of non-domesticated animals in urban areas will likely result in increased numbers of bites and, possibly, atypical hand infections,” the researchers point out. “An increasing turkey population in New York State is causing distress among civilians and postal workers. Pasteurella may be responsible for infections from wounds caused by turkeys. Urban coyotes are spotted on streets and outside storefronts in cities such as New York and Chicago, and have been thought to instigate altercations with domestic animals and occasionally result in human bites. Urban areas are expanding, the global human population is increasing, and animals and humans are forced to live (not always peacefully) among each other.”