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Feature Article

Human and animal bites: managing and preventing infection

STEPHEN MUHI, JUSTIN DENHOLM
OPEN ACCESS

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Abstract

Animal bites are an increasing public health problem, with half the Australian population expected to experience a significant animal bite at some time in their life. Infections from bites can range from the self-limiting to the life-threatening, with characteristics often dependent on the specific animal inflicting the bite.

Key Points

  • The nature of the bite, the species of the biting animal and the conditions of the host must all be considered when managing patients with bite injuries.
  • Although some overlap exists, the profile of the infection transmitted differs depending on the animal inflicting the bite.
  • Human bites result in greater infection and complication rates than other animal bites and are typically polymicrobial.
  • Dogs are responsible for most mammalian bites, with almost 20% of these bites becoming infected, followed by cats, with up to 80% of cat bites becoming infected.
  • Immediate management of bites includes assessment, surgery, antibiotic therapy and tetanus toxoid vaccination.
  • GPs have an important role in preventing bite wounds, and follow up of patients treated for bite wounds represents an important opportunity to educate, and offer vaccinations to, those at risk of further bites.

    Picture credit: © Schankz/stock.adobe.com

Human and animal bites may lead to serious injury, including transmission of infection to the recipient. The nature of the bite, the species of the animal and the conditions of the host are all factors to consider when managing a patient with a bite injury. The organisms involved in infection often originate from the oral cavity of the offending biter, as well as the environment where the injury has occurred.1 Although some overlap exists, the profile of infection transmitted differs depending on the animal inflicting the bite.

In one Australian study, dog bites represented the vast majority of bite injuries (79.6%), followed by human bites (8.7%), cat bites (7.2%), horse bites (1%) and rat bites (0.8%).2 Many Australian households report pet ownership, and exotic animals are becoming increasingly popular as pets. Patients who are immunocompromised are at a higher risk of infection,3 as are people with more comorbidities. Urbanisation has brought humans in close proximity to our native species, and increasing travel abroad brings people into proximity with less-familiar species as well as emerging zoonoses.

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Animal bites are a growing public health risk, and half of all Australians will experience a significant animal bite at some time in their life.4 The management of animal bites should involve an integrated approach that includes careful consideration of the human–animal–ecosystem interaction.

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This article reviews the characteristics of some of the infections from bites by a range of domestic, occupational and exotic animal species as well as humans; describes the immediate management of bites; and ­discusses strategies to prevent bites and minimise infective complications. Arthropod bites are not discussed.

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Dr Muhi is an Infectious Diseases Registrar at the Victorian Infectious Diseases Service, Royal Melbourne Hospital. Associate Professor Denholm is Medical Director of the Victorian Tuberculosis Program; Senior Staff Specialist at the Victorian Infectious Diseases Service, Royal Melbourne Hospital; and Principal Research Fellow in the Department of Microbiology and Immunology, University of Melbourne, Melbourne, Vic.