Reported Toxicities in Reptiles
Reported Toxicities in Reptiles
Some plants produce very powerful poisons. This section examines more frequently encountered plant poisoning and those commonly reported in the literature.
The heath family plants (azaleas, laurel, rhododendrons) are commonly planted in the United States as ornamental shrubbery. The toxin is found in the stems, leaves, flowers and nectar. No antidote exist; treatment is supportive. We have seen two iguanas stricken after eating azalea plants, one of which died. Both lizards were recumbent and nonresponive a few hours after ingestion.
Ground hemlock, Florida yew, English yew, Pacific yew, and Japanese yew are all members of a group that contains taxine. The bark, leaves, and seeds are poisonous but not the red fruit surrounding the seeds of these ornamental shrubs. No antidote exists.
Easter lily, tiger lily, day lily, Japanese showy lily, and Asiatic lily are known to be poisonous to cats by causing renal toxicosis. All parts of the plant are poisonous. ln addition, lily of the valley contains a potent cardiac glycoside. We have administered activated charcoal to an iguana that ingested Easter lilies. The animal survived with supportive therapy including fluids, warmth, and oxygen.
The seeds of apples, apricots, cherries, peach, plums, and the jetberry bush contain cyanogenic glycosides. The seeds are dangerous if the seed capsule is broken. The onset of clinical signs may be very rapid, and death can occur suddenly.
Avocado (Persea americana)
Avocado (Persea americana) has been shown to be toxic to rabbits, mice, and caged birds. All above-ground parts of the plant are toxic. Mader (personal communication) reports observing Green Iguanas (Iguana iguana) in the wild eating avocados that have fallen on the ground. However, with all the negative information available regarding ingestion of avocados, they should not be included in the diet of herbivorous captive reptiles until more are known concerning the nature of avocado poisoning.
Ricins - Castor Bean intoxication
Castor bean plants contain ricins, a potent toxin that stops protein synthesis. The poison is present ín the whole plant but most concentrated in the seed. No known antidote is available.
Cycad (Sago) Palms
These palms are used as houseplants and are naturally occurring in tropical and sub tropical regions. All parts of the plant are toxic. Gastrointestinal signs generally appear within 24 hours of ingestion. No antidote exists; treatment is supportive.
Holly, Mistletoe, Poinsettia
During the holiday season, several potentially toxic plants are often brought into the home. Although their toxicity is exaggerated, reptiles may blunder into them.
Holly (ilex spp.) Includes English or Christmas holly, American or white holly, and winterberry. No antidote exists, and treatment is symptomatic. In mammalian companion animals, these types of poisoning are not lethal.
Mistletoe (Phoradendron spp.) No antidote is available and treatment is supportive. In human children and mammalian companion animals, this intoxication is not lethal.
Poinsettia (Euphorbia pulcherrima) Possesses a milky sap rich in diterpenoids. These molecules are fairly irritating to the skin, mucous membranes, and gastrointestinal tract. Reports of toxicity stem from a single account.
Plants Containing Cardiac Glycosides.
Several plants contain cardiac glycosides, including oleander (Nerium oleander), foxglove (Digitalis purpurea), and Lily of the valley (Convallaria majalis). For oleander, all parts of the leaf are poisonous; a single leaf well chewed has been reported to be lethal. Foxglove leaves and seeds are toxic. Lily of the Valley poisoning comes from leaves, flowers, and root.
lvy (Hedera spp.) is used in greenhouses, as a houseplant, and as a ground cover. English ivy, Irish ivy, Persian ivy, Atlantic ivy, etc. are all potentially toxic. Most ingestion are not serious, and treatment is supportive.
Plants Containing Nicotine
Tobacco products including pipe tobacco, cigarettes, cigars, chewing tobacco, and snuff contain the alkaloid nicotine. Captive reptiles may ingest cigar and cigarette butts, pipe tobacco chewing tobacco, or nicotine patches and gums. We have seen death in one tortoise and one Green Iguana after eating several cigarette butts. Clinical signs of high-dose nicotine intoxication include excitement followed by depression,
diarrhea, seizures, coma, and respiratory or cardiac arrest.
Oak trees are found almost worldwide. Acorn, buds, twigs, and leaves have been implicated, but most incidents of intoxication involve either immature leaves in the spring or freshly fallen acorns in the spring. Ingestion of toxic amounts of oak have been shown to cause ulcerative lesions in the upper and lower gastrointestinal tract, liver lesions, and necrosis of proximal renal tubular epithelial cells.
A fatal episode of oak intoxication has been reported in a tortoise. An African Spurred tortoise was found dead in an outdoor enclosure where numerous oak trees hung over and into the area. On necropsy, the stomach of the tortoise was markedly distended with partially digested oak leaves.
Marijuana continues to be by far the most used illicit drug in the United States. Clinical signs after ingestion of marijuana include mydriasis, weakness, ataxia, bradycardia, hypothermia, and stupor. Activated charcoal administration is recommended. We have seen two reptiles ingest fairly large amounts of marijuana . A 10-pound Sulcata Tortoise showed no effects after eating four marijuana cigarettes. However, a 6-pound male Green Iguana was stuporous after eating into "baggie" of marijuana and needed support.
Information Provided by DR Doug Mader.
Various "over-the-counter" drugs kept on nightstands, kitchen counters, or bathroom shelves may be encountered by captive reptiles given free range in the house. For their own
safety, captive animals
should be confined and all medications kept in their original container- in child-proof and animal-proof cabinets.
From a book by Small Animal Toxicology, By Michael Edward Peterson, Patricia A. Talcott
An ever expanding array of substances has been shown to be toxic to lizards, snakes, and turtles. Intoxication in reptiles, once merely an anecdotal domain, has grown tremendously in the last few years thanks to more detailed published accounts of poisoning and some in-depth pharmacological studies. Certainly, thousands of different molecules have the capacity to poison living reptiles. Unfortunately, less than 5% of all potential toxins have antidotes or effective physiologic antagonists. This index of poisons, although by no means complete focuses on the most common poisonings of reptiles, their mechanisms of action, and their potential treatments.
Ivermectin is an antiparasitic medication prescribed for reptiles. It is available as an injectable, a spray, andan oral formulation. It has activity against a variety of parasites, including nematodes, arthropods, and arachnids. Ivermectin is active against intestinal parasite, mites, microfilariae, and developing larvae.
Can cause depression, paralysis, coma, and death. Ivermectin toxicity has been reported in severalspecies of lizards, tortoises, turtles and snakes. Ball Pythons in particular may show mild neurologic signs when treated.
No known antidote or physiologic antagonist exist for ivermectin. Treatment is supportive and should include decontamination of any topical prays with soap and water, fluid therapy, nutritional support, monitoring of electrolytes, and respiratory (ventilator) support.
ORGANOPHOSPHATES AND CARBAMATES
Organophosphates are the most commonly used insecticides worldwide. In the United States alone, 250 million pounds of organophosphates are used annually at a cost of $2.4 billion to produce. They are found in agriculture, in the home, and on or around various domestic animals. For animal use as insecticides, they are formulated as dips, prays, topical medications, systemic parasitic agents, and flea collars. They are the active ingredient in a long list of products. Dursban, Proban, ProSpot, Sevin etc. Organophosphatcs are readily absorbed by all routes-dermal, respiratory, gastrointestinal, and conjunctival.
Clinical signs seen in reptiles include salivation, ataxia, muscle fasciculations, inability to right themselves, coma, and respiratory arrest. Death results from massive respiratory secretions, bronchiolar constriction, and effects on respiratory centers in the medulla, leading to the cessation of breathing.
Animals with dermal exposure should be washed with a mild dishwashing detergent and copious amounts of water. Animals should be dried after rinsing to prevent further uptake of the insecticide. The need for fluid therapy to counter dehydrabon and electrolyte imbalances should be considered. The specific physiologic antidote, the muscarinic antagonist atropine, should be given. This should help with salivation, bronchospasm, and dyspnea. Diazepam my be given as needed for seizures. Prognosis is dependent on dosage, duration of exposure, and size of the animal.
VITAMIN A TOXICITY
Vitamin A is necessary for normal skin and periocular tissue health, particularly in chelonians. Turtles with hypovitaminosis A typically show ocular discharge, palpebral edema, blindness, hyperkeratosis of skin and mouthparts, and aural abscesses. Patients can improve with vitamin A supplementation (2000 IU / kg every 7 days) and better diets. Unfortunately, excessive iatrogenic administration of vitamin A can cause its own set of problems. This can cause inappetence, full-thickness skin sloughing, secondary bacterial infection, discoloration of the skin, and extreme lethargy.
VITAMIN D TOXICITY
Calcium supplements sometimes include vitamin D. Cholecalciferol (vitamin D3) may be listed on food labels as cholecalciferol, animal sterol, D-activated animal sterol, irradiated animal sterol, or vitamin D3.
Owners, breeders, and veterinarians often oversupplement captive reptiles with disastrous results. Dosages of 50 to 1000 times the minimum daily requirement are often given for weeks to months. Minimum daily requirements have not been established for reptiles. The mechanism of action of the toxicity of vitamin D is related to the hypercalcemia it induces. This prolonged hypercalcemia causes dystrophic calcification of the gastrointestinal tissues, the kidneys, lungs, blood vessels, and joints. Complete removal of vitamin D -containing supplements and cortisone may help control hypercalcemia, but resolution of soft-tissue calcification may not be successful. Clinical signs include depression, weakness and anorexia. Eventually, signs of renal disease become evident as glomerular filtration rate decrease.
In light of the inherent calcium problems of captive reptiles, veterinarians must counsel clients about proper husbandry, nutrition, and dietary requirements and ensure that no supplements are given to animals without veterinary approval. Veterinarians must provide up-to-date advice to reptile caretakers concerning every aspect of the health of the animals. 1069
Zinc is an essential trace element. It is necessary for the synthesis of more than 200 enzymes required for cell division, growth, and gene expression. Zinc toxicosis may result from overzealous administration of supplements, ingestion of galvanized metal objects, zinc oxide ointment, or ingestion of pennies. Before 1982, pennies were more than 90% copper; since that time, they are 97% zinc. We have seen two iguanas and one snake with gastrointestinal tracts full of pennies that showed signs of zinc toxicity.
Clinical signs o zinc toxicosis depend on the amount and form of the zinc ingested. Signs are delayed if coins are the source of the zinc. As few as one or two pennies can cause a toxicity. First, the animal may be anorectic and lethargic, and the zinc ingestion may mimic a gastrointestinal enteritis. This is followed by intravascular hemolysis, hemoglobinemia, yellow discoloration of the skin and mucous membranes, and weight loss.
Soaking living animals in any solution can be potentially life threatening. Recently, turtles soaked for 1 hour in chlorhexidine scrub have been shown to become intoxicated.
Reptile caretakers often supplement the diet of captive animals with freshly caught insects. Fireflies of the genus Photinus have been shown to contain steroidal pyrones that are poisonous. Less than one half
of a firefly could be lethal to a 100-g lizard. Bearded Dragons have shown fatal intoxication after ingestion of fireflies. In both cases documented, the lizards showed sign 30 to 60 minutes after ingestion. Clinical signs included pronounced oral gaping, intense color change in the neck area, and dyspnea. Both animals died
within 90 minutes of eating the firefly. At present, no effective therapy is known.
Spiders, birds, and several species of lizard have been shown to avoid fireflies. Bearded Dragons has no natural contact with Photinus species of fireflies and thus may exhibit no sell-protective avoidance behavior.
Fenbendazole is a benzimidazole type of antiparasitic drug. It is safe and effective for treatment of many helminth parasites in animals. Recently, evidence of fenbendazole overdose has been reported in individuals of a small snake species given an exceedingly large dose of the drug.
Metronidazole is used as an antibacterial, an antiprotozoal, and an appetite stimulant in reptiles. It is formulated as a suspension, as an injectable, and as a tablet. Strict attention must be paid to the dosage, the frequency, and the size of the animal.
The most severe side effect of metronidazole is dose-related CNS toxidity. High dosages can cause ataxia, inability to walk, nystagmus, opisthotonos, tremors of the lumbar muscle and hind limbs, seizures, and death.
Treatment is symptomatic and supportive and involves administration of fluids and both warmth and respiratory support. In severe cases, the patient may need to be placed on a ventilator.
PYRETHRINS AND PYRETHROIDS
Pyrethrin is the oldest used botanic insecticide. A variety of diluted pyrethrin containing and pyrethroid-containing spray have been recommended for reptiles for treatment of parasites.
Animal can have signs develop with in 15 minutes of application. Signs include salivation, ataxia, inability to right themselves, and muscle fasciculations. Reactions can happen at much lower doses than expected.
No known antidote exist for these molecules. If caught early enough, treatment for involves dermal decontamination.
Animals should be kept out of recently bleached cage a minimum of 24 hours to prevent respiratory tract
irritation. Cages should be allowed to air out at least this long. In addition, residual disinfectant can be removed by wiping with a clean cloth or towel and exposing the area to direct sunlight for a few hours.
A variety of fungal infections have been documented in reptiles. Ranging from dermatophytes to systemic mycotic infections, these conditions are treated with a variety of antifungal medications. Because of the often small size of the reptilian patient, the mechanism of action of these drugs, improper treatment with antifungals can lead to serious intoxications.
Antifungal drugs available for reptiles which can cause intoxication:
Imidazole (Ketoconazole) and Triazoles (Fluconazol and Itraconazole)
Book: Reptile Medicine and Surgery. Douglas R. Mader, MS, DVM, DABVP Diplomate, American Board of Veterinary Practitioners (CA) Fellow, Royal Society of Medicine Marathon Veterinary Hospital Marathon, Flori.da SAUNDERS. With 72 Contributing Authors
Provided by Sam Pascucci
Florida Iguana & Tortoises Breeders.