By Brynne Stumpe, 2015 DVM Candidate
University of Minnesota College of Veterinary Medicine
Extern, Pet Poison Helpline®

Toxins can be a serious problem in companion birds due to several factors including their size, efficient respiratory system, and curious nature.  In addition, many owners may be unaware that certain substances can be toxic to their birds.  The following is a list of 5 common toxins to be aware of for these pets.

Lead

• Lead poisoning has historically been the most common metal poisoning in caged birds but, due to increased knowledge of the human health problems caused by lead, its use in the home has significantly decreased.
• Sources: Lead-based paint, foil from some champagne and wine bottles, curtain weights, bells with lead clappers, imported bird toys, stained glass.
• Clinical Signs: Depression, weakness, food refusal (anorexia), weight loss, vomiting/regurgitation, increased thirst and urination (polyuria/polydipsia), seizures, hemoglobinuria, diarrhea.  Clinical pathology can include heterophilia, hypochromic regenerative anemia, cytoplasmic vacuolization of red blood cells, and increases in liver enzymes (LDH, AST), muscle enzymes (CPK), and uric acid (indicator of renal function).
• Diagnosis: History, clinical signs, clinical pathology, blood lead concentration, evidence of radiopaque material in the GI tract.
• Treatment: Remove lead object via crop gavage, cathartics, and/or endoscopy. Chelation therapy can be performed with succimer and/or calcium EDTA.
• Public Health Consideration: Pets have long served as sentinels for lead poisoning in people, especially children. If a bird or any pet in the home is diagnosed with lead poisoning, always recommend that people in the home, especially the children, should be tested too.

Zinc

• Zinc poisoning is the most common metal poisoning in caged birds and occurs following ingestion of zinc-containing items.
• Sources: Galvanized products such as wire cages, mesh, staples, nails, and toys. (Galvanization is the process of coating a metal with an alloy containing more than 98% zinc which is done to protect against rusting.) Additional sources include fertilizers, some paints, zinc pyrithione shampoos, zinc oxide, and pennies minted after 1982.
• Clinical Signs: Similar to those seen with lead poisoning but hemoglobinuria has not been reported.
• Diagnosis: History, clinical signs, radiographs, pathology, elevated zinc concentrations in serum, plasma, or tissues.  Blood samples should be collected in royal blue-top tubes to avoid zinc contamination leaching into the sample.
• Treatment: Removal of zinc from GI tract is typically sufficient provided the animal is still relatively stable.  If zinc cannot be removed promptly, chelation with calcium EDTA can be performed.

Avocado

• All owners of caged birds must be advised never to feed avocado as it is extremely poisonous and can result in sudden death.
• Source: Clinical signs are believed to be caused by the compound persin, which is found in all parts of avocados in the Persea genus (the most available genus for human consumption) and in the leaves and bark of their trees.
• Clinical Signs: Agitation, feather pulling, lethargy, food refusal (anorexia), dyspnea (difficulty breathing), pericardial effusion (fluid surrounding the heart), pleural and hepatic congestion (blood in the thoracic cavity and liver), death.
• Diagnosis: History and clinical signs
• Treatment: No antidote exists. Supportive care includes oxygen, fluids, sedatives, removal of avocado from crop or proventriculus with lavage and activated charcoal.
• Lethal Doses: The lethal dose in budgerigars is 3.5 g in an average 35 g bird.  The lethal dose in cockatiels is 20-30 g.

Polytetrafluoroethylene (PTFE) or “Teflon toxicity”

• Sources: Nonstick surfaces on Teflon cookware, drip pans, heat lamp covers, irons, ironing board covers; stain-guard treatments for upholstery.  Toxic particulates and gases are produced when the surface is heated to 280^o C (536^o F).  This can occur when a pan boils dry or an empty pan is heated on high (poisoning is not expected during routine cooking).
• Clinical Signs: Acute death due to respiratory failure. Mild exposures may cause dyspnea (difficulty breathing), ataxia (incoordination), depression, or anxious behavior.
• Diagnosis: History, clinical signs, pathologic lesions (fluid and blood-filled lungs).
• Treatment: No antidote exists. Supportive care includes oxygen, anti-inflammatory drugs, diuretics, analgesics, bronchodilators, antibiotics, topical ophthalmic ointment (if ocular irritation).  Prognosis is guarded to poor.

Other Inhaled Toxins

• Birds have a very efficient system for gas exchange.  Compared to mammals, more oxygen is transferred into the blood with each breath.  Unfortunately, this means more toxins are also transferred into the bird with each breath, making them more sensitive to harm from inhaled toxins.  This is the reason canaries were historically used in coal mines to warn for the presence of carbon monoxide and other noxious gases.
• Sources: Gasses like carbon monoxide, smoke from tobacco products, and fumes from new carpets and furniture, air fresheners, scented candles, paints, glues, household cleaning products, mothballs, hair spray, and nail polish can all be harmful when they are in close proximity to birds.  With appropriate ventilation and use, these substances may not be toxic.
• Clinical Signs: Variable based on source and level of exposure.  Acute death, dyspnea (difficulty breathing), eye irritation, nasal passage irritation, possible immunosuppression.
• Diagnosis: History and clinical signs.
• Treatment: Similar to PTFE (Teflon).
• How to Protect Companion Birds: When using products that give off strong fumes, it’s best to move the bird to a separate room in the home and open windows to ensure plenty of ventilation. Placing a towel under the door of the bird’s room can also help reduce fumes exposure. When painting walls in a home, the use of VOC-free paints (volatile organic compounds) may be safer. Alternatively, consider boarding birds off-site during construction, remodeling, or intense whole-house cleaning until odors have dissipated.

Works Cited

Burmeister, Christian A. and Yunker, Jennifer. (2013). Avian Avocado Toxicosis. Veterinary Technician.

Degernes, Laurel. (2010, August). Avian Toxicology: Common Problems. Presented at the Annual Conference of the Association of Avian Veterinarians, San Diego, CA.

Jones, Michael P. (2007, February). Avian Toxicology. Presented at Western Veterinary Conference, Las Vegas, NV.

LaBonde, Jerry. (2006, August). Avian Toxicology. Presented at the Annual Conference of the Association of Avian Veterinarians, San Antonio, TX.

Lightfoot, Teresa L, and Yeager, Julie M. (2008). Pet bird toxicity and related environmental concerns. Veterinary Clinics of North America: Exotic Animal Practice, 11(2), 229-259.