Canis ISSN: 2398-2942

Venomous lizard bites

Contributor(s): Rosalind Dalefield, Dawn Ruben

Introduction

  • Only two of the approximately 3000 known lizard species are venomous. Both of these belong to the genusHeloderma. They are the gila monster,Heloderma suspectum, and the Mexican beaded lizard,Heloderma horridum.
  • Bites are extremely rare but can be serious.

Pathogenesis

Etiology

  • Envenomation by means of a lizard bite.

Predisposing factors

General
  • Helodermalizards are not aggressive, but will bite if provoked. As desert areas become more popular as recreation areas, the risk that dogs will investigateHelodermalizards too closely increases.

Pathophysiology

  • The major toxic factor in the venom is gilatoxin. It does not contain proteolytic, hemorrhagic or hemolytic factors, but does contain enzymes including phospholipase A and hyaluronidase.
  • The venom glands bathe the teeth. The upper teeth are grooved, allowing venom to enter the bite wound.
  • The wound may become infected with bacteria, and there is a risk of tetanus Tetanus.

Timecourse

  • The longer the lizard bites and holds on, the greater the envenomation. Pets may present with the lizard still gripping them.
  • Edema of the wound may develop rapidly over 15 minutes or may follow a more protracted course of 4 to 8 hours.
  • Dogs usually recover fully from aHelodermalizard bite within 5 days.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

Other sources of information

  • Osweiler G D (1996) Toxicology. Williams and Wilkins.
  • Fowler M E (1993) Veterinary Zootoxicology .CRC Press.

Organisation(s)


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