Felis ISSN 2398-2950

Toad poisoning

Contributor(s): Rosalind Dalefield

Introduction

  • Cause: all toads are poisonous either by being eaten or by being mouthed.
  • The native British toad, Bufus vulgaris is much less toxic than some exotic species, Bufus blombergiBufus alvariusBufus marinus.
  • Signs: inflammation of the mouth and pharynx with ptyalism and retching, abdominal pain, vomiting, neurological and cardiovascular effects.
  • In Britain the signs are usually confined to local oral effects. Contact with exotic toads are more likely to cause the more severe systemic effects and these may be fatal.
  • Treatment: symptomatic.
  • Prognosis: good following exposure to native UK toads; otherwise guarded.

Pathogenesis

Etiology

  • Mouthing or eating toads.
  • Very occasionally there may be absorption of toxins through an open wound.

Predisposing factors

General

  • Outdoor or indoor/outdoor cats.
  • Some cats seem to particularly enjoy hunting frogs and toads.

Pathophysiology

  • Toad poisoning is most likely to occur in the summer when toads can be easily found in gardens. Bufus vulgaris hibernates in the winter and in the spring is breeding in ponds.
  • Venom is produced from toad skin glands as a defense mechanism.
  • The glands are concentrated on the dorsal body, especially in the paratoid glands on the back of the neck.
  • Using an active muscular process the glands can quickly exude a venomous liquid.
  • Cardioactive glycosides produced include bufagins, bufotoxins, bufotenins. Effects include digitalis-like and oxytocic (vasopressor) effects.

Other substances

  • Found in toad venom are adrenalin, cholesterol, ergosterol and 5-hydroxytryptamine (serotonin).
  • Mucous is produced from the skin at the same time as the venom as an additional protective device.
  • Toad venom is sticky and difficult for the affected animal to remove from their mouth.
  • Local irritation is the usual problem in Britain.
  • Venom in the mouth and pharynx is sticky and irritant.
  • Systemic signs are only likely with the British toad if it is eaten or if the affected cat is small or has an underlying problem such as asthma Allergic bronchitis or heart disease Heart: congestive heart failure.

Timecourse

  • It is a peracute onset for local irritation, ptyalism and retching.
  • Systemic signs take about 24 hours.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Palumbo N E, Perri S & Read G (1975) Experimental induction and treatment of toad poisoning in the dog. JAVMA 167 (11), 1000-1005 PubMed.
  • Bedford P G (1974) Toad venom toxicity and its clinical occurrence in small animals in the UK. Vet Rec 94 (26), 613-614 PubMed.
  • Perry B D & Bracegirdle J R (1973) Toad poisoning in small animals. Vet Rec 92 (22), 589-590 PubMed.
  • Otani A, Palumbo N & Read G (1969) Pharmacodynamics and treatment of mammals poisoned by Bufo marinus toxin. Am J Vet Res 30 (10), 1865-1872 PubMed.

Other sources of information

  • Palumbo N E & Perri S F (1983) Toad poisoning. In: Current Veterinary Therapy VII.W B Saunders, Philadelphia, pp 160-162.
  • Fowler ME (1993) Veterinary Zootoxicology. CRC Press Inc.
  • Osweiler G (1996) Toxicology. Williams and Wilkins.
  • Peterson ME and Roberts BK (2001) Amphibian Toxins. In: Small Animal Toxicology.Eds Peterson & Talcott. WB Saunders.

Organisation(s)


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