Bufo Toad Envenomation

Patty Khuly

Summary

Toads of the genus Bufo, live in many parts of the world and, unbeknownst to many pet owners, can be toxic to dogs. The Bufus marinus toad species is especially common in southern Florida. Many thousands of dogs are exposed to these poisonous toads every year in places like this.

Although toads cannot sting or bite dogs, they can nonetheless evenomate them via their skin glands (parotid glands). These glands secrete a venom of variable toxicity, depending on the species of toad, which covers their body in a protective film.

Symptoms and Identification

Dogs typically present with signs that occur as a result of local irritation to the oral mucous membranes or systemic signs of gastrointestinal toxicity, neurotoxicity and cardiotoxicity. Signs usually manifest within minutes of contact with the venom.

Local irritation: Hypersalivation, bright pink oral mucous membranes
Gastrointestinal toxicity: Vomiting, diarrhea, fecal incontinence
Neurotoxicity: Ataxia (loss of balance), seizures, depression, walking in a circle, papillary changes, and collapse
Cardiotoxicity: Abnormal heart rhythms

Less common clinical signs include excitement, progressive muscular paralysis, blindness and vocalization.

Knowledge of contact with a Bufo toad is the typical means of diagnosis. But in many cases, the diagnosis can be made presumptively depending on the history (being out of doors at night during the wetter seasons of the year), geographic location, and the dog’s clinical signs.

Affected Breeds

Any breed of dog is susceptible to the effects of the Bufo toad toxin. Some dogs, however, are more likely to have a high drive to attack these animals. Dogs with high prey drives, especially breeds with a special interest in small animals (such as rats) may be more inclined to receive a higher dose of Bufo toxin. As such, terrier breeds may be more predisposed than others.

Treatment

Treatment of Bufo toad envenomation usually depends on the dose an animal has received. In all cases, however, dogs should have their mouths rinsed out with water immediately upon suspicion of toad envenomation. A hose or bath nozzle may be used to rinse out the oral cavity, taking care not to allow aspiration.

All dogs should be taken to a veterinary facility after exposure, but those who begin to show neurological signs should be rushed there immediately. Supportive care, including intravenous fluid and anti-seizure medication (such as diazepam or propoful) administration is the mainstay of treatment. Symptomatic treatment of any gastrointestinal signs is also undertaken at this time.

For patients who have received a large dose of Bufo toad toxin, intensive care may be required to keep recurrent seizures at bay and to monitor the heart for signs of cardiotoxicity.

Veterinary Cost

The cost of Bufo toad envenomation depends to a large extent on the degree to which a dog is exposed and, consequently, to the dose of toxin he or she received. If was a simple lick or quick bite, resulting in minimal toxin absorption, dogs are likely to fare well –– sometimes even without any veterinary intervention at all (though it’s strongly recommended all dogs be examined by a veterinarian after any Bufo toad toxin exposure).

Others, however, may require rapid emergency intervention and intensive care after long bouts of seizuring. Depending on the dose of toxin and length of time elapsed before treatment, dogs may require one or more days of intensive care. Each day of care can amount to $1,000 or more. This will vary depending on the geographic locale and level of care elected (general practice vs. specialty center).

Prevention

Preventing exposure to the Bufo toad is the only sure means of preventing envenomation.

Dog owners who live in Bufo toad-specific locales are urged to keep a watchful eye out during the wetter seasons of the year. This is when toads are more active and likely to find itself in a dog’s path.

Since toads are attracted to pet foods, keeping bowls out of doors is not recommended. Removing toads from a dog’s yard is considered helpful but it’s no sure means of prevention if the yard is otherwise hospitable to them. Some dog owners have attempted to shore up fencing with chicken wire or predator fencing with mixed results.


References

Barbosa CM; Medeiros MS; Riani Costa CCM; Camplesi AC; Sakate M.J. Toad poisoning in three dogs: case reports. Venom. Anim. Toxins incl. Trop. Dis vol.15 no.4 Botucatu 2009.

M. Sakate, P.C. Lucas de Oliveira. Toad envenoming in dogs: effects and treatment. J. Venom. Anim. Toxins vol.6 n.1 Botucatu 2000.