Ask the Edmonds Vet: Still more plants poisonous to animals

By Dr. David Gross

Fifth in the series

The deadly Sago Palm (Coontie Palm, Cardboard Palm, Cycads and Zamias) is extremely poisonous to animals and humans if ingested. Dogs and cats are particularly at risk since they seem to find the plant very palatable. Clinical signs usually develop within 12 hours of ingesting the plant and may include signs of gastroenteritis, generalized weakness, seizures and hepatotoxicity (liver damage) characterized by icterus (yellow color of the mucous membranes and sclera of the eyes), and ascites (accumulation of fluid in the abdomen).

Pets may appear bruised, have nose bleeds and bloody stools with bloody discharges from the anus in the absence of fecal matter. The Animal Poison Control Center of the ASPCA says fatality rates can be between 50 and 75 percent from ingestion of this plant. Over the past five years, the incidence of reported pet poisonings from the Sago has increased markedly. All parts of the plant are toxic but the seeds contain the highest concentrations of ceasing, the major toxin and responsible for the gastrointestinal damage, but these plants also contain Beta-methyl amino L-alanine, a neurotoxin, and an unidentified toxin observed to cause hindlimb paralysis in cattle.

It is particularly important to get your animal to a veterinarian immediately if you suspect it has ingested any portion of the Sago Palm, but veterinary care is highly recommended following exposure to any of the plants mentioned in this series.

There are about 250 different species of plants in the Ericaceous family including; Rhododendrons, Azaleas, and Rosebays. Others include; Andromeda Japonica (Lily-of-the Valley Bush) Black Laurel (Dog Hobble, Dog Laurel, Fetter Bush, Sierra Laurel, Staggerbush and Male berry). Depending upon the time of year and the specific plant, ingestion of only a few leaves can cause problems. Horses and cattle will usually not eat these plants, unless nothing else is available, but sheep and goats seem more inclined.

The Grayanotoxins found in these plants interfere with normal skeletal and cardiac muscle function as well as normal nerve function. Clinical signs can appear within a few hours following ingestion and in usually include gastroenteritis (inflammation of the stomach and intestines), hyper salivation (drooling), anorexia (loss of appetite), diarrhea, abdominal pain, depression and weakness. These signs progress to loss of coordination, stupor, leg paralysis and weak heart rate, and the animals can become recumbent for two days or more. If untreated, the animals may become comatose and die.

My wife and I have had Coleus, also known as Indian Borage, Bread and Butter Plant, Spanish Thyme, East Indian Thyme, Stinging Thyme, Country Borage, Winterberry and many other common names, growing in our home for years. This plant contains essential oils and ingestion can result in vomiting, diarrhea, either can occasionally be bloody, anorexia and the potential for photosensitivity. Many cultivars of Eucalyptus also contain essential oils (eucalyptol) and can cause irritation of the mucous membranes resulting in drooling, vomiting, diarrhea followed by depression and weakness. The Bergamot Orange (Bergamot, Citrus Bergama) contains essential oils and psoralens and ingestion can cause gastroenteritis and photosensitivity (sensitivity to sunlight).

Cow Parsnip (Giant Hogweed) contains Furanocoumarins causing photosensitization resulting in an ulcerative (ulcers) and exudative (pus) dermatitis as well as eye problems. Brunfelsia (Yesterday, Today, Tomorrow, Kiss-Me-Quick, Lady-of-the-Night, Franciscan Rain Tree, where do they get these names?) contain the toxic principle Brunfelsamidine, which can cause gastroenteritis, coughing, lethargy, tremors and seizures, with signs lasting for days.

Cowbane, also known as Water Hemlock and Poison Parsnip, contains Cicutoxin. Ingestion can cause gastroenteritis, fever, extreme abdominal pain, tremors, dilated pupils, respiratory depression and death. Angelica Tree (Hercules Club, Devil’s Walking Stick, Prickly Ash, Prickly Elder) accumulate Aralin. Horses, dogs and cats can develop skin and oral irritation, hyper salivation, and gastroenteritis following exposure to this plant.

Solanaceae plants include the Tomato, European Bittersweet (Climbing Nightshade, Deadly Nightshade) and the Ornamental Pepper (Natal Cherry, Winter Cherry, Jerusalem Cherry). Ingestion can result in gastroenteritis with possible GI ulceration, seizures, depression, respiratory depression, hypotension (low blood pressure), shock, weakness, and dilated pupils. Another toxic plant in the Solanaceae family is Nicotiana (Tree Tobacco, Tobacco, Mustard Tree). This plant contains nicotine and ingestion can result in hyper-excitability followed by depression, gastroenteritis, paralysis and death.

Dr. David Gross of Edmonds graduated from Colorado State University’s veterinary school in 1960 and was in private practice for 10 years. He retired in 2006 as Professor and Head of Veterinary Biosciences, at the University of Illinois, Urbana-Champaign. Dr. Gross is the author of “Animals Don’t Blush,” which describes the unique patients and even more unique clients of a veterinary practice in Sidney, Montana in the early 1960s.

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