Bufo Toads: Poisonous to Pets

Filed Under: Dogs, Cats, Poisoning

Think toads are harmless? Do you think it’s alright if your dog or cat decides on a frog-leg snack? If you live in a warmer part of the world you might just want to rethink your position. Especially large or colorful frogs may be hazardous to the health of your pets. In fact, toads were responsible for the 8th most common way pets were poisoned during 2007 in the United States.

The poisoning of the Bufo species of frogs is quite varied with the most toxic poisons being produced by the larger members of this group. The cane or marine toad, also known as “Bufo marinus,” is the largest member of this species. B. marinus is found in Florida, Texas, Hawaii, the Caribbean, Central and South America, Fiji, Australia, the Philippines, and the Marianas. Bufo alvarius is found in the Imperial Valley of California and in the Colorado River basin between Arizona and California. Bufo blombergi is found only in Colombia and Bufo regularis is found in Ethiopia.

Toxins are secreted in a milky substance from the toad’s rather large parotid glands, which are an aggregation of granular glands (modified mucous glands) located at the back of the head, behind (caudal) and to the side (lateral) of the ears. These toxins will burn the eyes, inflame the skin, and are rapidly absorbed across the mucus membranes of the victim into their circulation.

There are a wide variety of toxins secreted by the Bufo Toad including dopamine, epinephrine, norepinephrine, serotonin, cardiac glycosides (bufagenins and bufotoxins), various cardenolides, and bufadenolides which are steroid-like in structure and have a lactone ring.

Bufo marinus may grow to approximately the size of a salad plate and become up to four pounds in weight. These giant toads are heavily built and have relatively short legs. Adult frogs will have a warty skin with their color ranging from tan to dull green or black with a light underside. These toads are relatively slow and have therefore developed their toxic secretions to protect themselves from predators.

Bufo frogs will eat almost anything they can catch and will eat any animal they can swallow. In fact, they were originally released in sugar cane fields to help control rats and mice. This toad will also sit in a bowl and eat dog or cat food left out for pets.

Dogs tend to be the most commonly affected animals, being curious or by hunting the frog. The first clinical sign of a problem is pawing at the mouth and anxiety. The mucus membranes will appear brick red in color and the affected animal will hypersalivate (foam at the mouth), will often vomit, and may vocalize. Patients will exhibit nystagmus (rotation of the eyes back and forth), rapidly become disoriented, and will progress to a full stupor and death. Death may occur in as little as 15 minutes. Convulsions are not uncommon. Death typically results from cardiac arrhythmias.

Initial treatment involves constraining the absorption of the toxin by copiously rinsing the mouth of the victim with water while at the same time trying to prevent swallowing of the toxin. In cases of ingestion, the toads may be removed surgically or by an endoscope. Alternatively, activated charcoal with a cathartic may be used to prevent toxin absorption and aid in the removal of the toad from the gastrointestinal tract. Seizures should be controlled and cardiac function assessed by an ECG and treated as necessary. Bradycardia (slow heart rate) may be treated with atropine, while tachycardia (rapid heart rate) is treated with propranolol and ventricular tachycardia with lidocaine. With severe clinical symptoms or when available, Digibind or Digoxin Immune Fab, available from Glaxo Smith Klein, may be used to bind to the digoxin-like components of the toxin, but it is expensive.

The temperature of a patient should be monitored because hyperthermia (elevation of temperature) is often seen as a sequela following the intense muscular activity induced from the various toxins.

When Bufo frogs are native to your area, the best way to prevent a toad in your yard is to place a 1/8? mesh screen around the outside of your fence. This screen needs to be buried 4? and should be extended at least 20? above the ground.

References:

Gupta, Ramesh. Veterinary Toxicology. Elsevier. 2007. Pp. 797-798.

LaBonde, Jerry Ed. Veterinary Clinics of North America, Exotic Animal Practice Toxicology. Saunders. Vol. 11, No. 2. May 2008. Pp. 385-386.

Smith, Bradford. Large Animal Internal Medicine. 2nd Edition. Mosby. 1996. P. 1881.

“Top 10 Pet Poisons.” Pet Age. June 2008. P. 55.

http://www.floridagardener.com/critters/BufoMarinus.htm

http://www.pgaa.com/CANINE/health/bufotoad.html

Topics: poisons, toxicity

Symptoms: anxiety, hypersalivation, nystagmus, seizures, vocalization, vomiting

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