Felis ISSN 2398-2950

Venomous animals of Australia

Contributor(s): Rosalind Dalefield, Dawn Ruben

Introduction

Pathogenesis

Etiology

  • Australian snake venoms contain a wide variety of toxic components including neurotoxins, lytic enzymes, coagulants, myolysins and cytotoxins. Neurotoxins are the most important components causing paralysis and respiratory failure.
  • Redback spider venom is primarily neurotoxic, interfering with neurotransmission and neuromuscular function.
  • Ixodes tick venom interferes with neuromuscular function. The mechanism is not fully understood.
  • Hymenoptera venoms are a complex mixture of toxic chemicals. Locally there is pain and swelling.  Systemic effects may include cardiovascular and respiratory collapse. CNS depression, nerve dysfunction and severe gastrointestinal effects have been reported in the dog. In the cat, bee venom has been shown to cause hypotension, bronchiolar contraction and derangement of cardiac conduction. Anaphylactic shock may also occur.

Timecourse

  • Onset of clinical signs of snake envenomation may be delayed 12 to 24 hours, so any cat suspected to have been bitten requires close observation.
  • Onset of clinical signs of Latrodectus envenomation occurs within 8 hours of the bite. Average survival time in cats is 115 hours. Cats exhibit paralytic signs relatively early.
  • Tick paralysis becomes apparent several days after the tick attaches, but progresses rapidly from first clinical signs to death.
  • Hymenoptera stings cause an immediate reaction.

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

  • Murray E Fowler (1992) Veterinary Zootoxicology. CRC Press
  • Malik R (1998) Tick Paralysis in the Cat. In: Clinical Toxicology, Proceedings 318, Post Graduate Foundation in Veterinary Science, University of Sydney.
  • Little P (1998) Spider Envenomation in Dogs and Cats. In: Clinical Toxicology, Proceedings 318, Post Graduate Foundation in Veterinary Science, University of Sydney.
  • FitzGerald MP (1998) Ixodes holocyclus poisoning. In: Clinical Toxicology, Proceedings 318, Post Graduate Foundation in Veterinary Science, University of Sydney.
  • Best P (1998) Snake Envenomation in Companion Animals In: Clinical Toxicology, Proceedings 318, Post Graduate Foundation in Veterinary Science, University of Sydney.


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