Poisoning from the intake of lead, zinc and occasionally copper is called “heavy metal” poisoning in birds and is one of the most common avian toxicities that we see at our Melbourne Bird Hospital in pet and aviary birds. Birds are often inquisitive and examine new objects and place then in their mouths. They like to chew on shiny objects. Toxicity n birds can result if the metallic object contains heavy metals. Stainless steel is safe for birds and an ideal product for feed dishes and cages. HMT in birds is largely a preventable disease and we will discuss how typical cases present to our Melbourne veterinary clinic and what steps owners can take to prevent heavy metal toxicity. The clinical signs in birds are related to effects on the nervous system, bloods cells, kidneys and intestines.
The birds may present with one or more of the following symptoms:
Lethargic and fluffed
Vomiting or regurgitation
Sometimes they will seizure
Pass watery green droppings
Severely affected birds may die suddenly
A more common syndrome is that of low level poisoning with vague clinical signs and pet birds that are just “not well”.
Lead poisoning in birds is regularly seen in pet birds and waterfowl in our Avian Veterinary Hospital . This is because sources of lead can be surprisingly common in household situation. The increase in awareness of the dangers of lead to humans has resulted in decreased the availability of lead to our pets. With the increased number of pet birds coming in for well bird exams and more awareness about sources of lead, many potential poisoning in birds are avoided. In lead toxicity in birds, there may be neurological signs (seizures, blindness and head tilt) or a wing droop or leg paralysis. There may also be “blood” present in the droppings called hemaglobinuria, which is not blood but breakdown product of blood. Common sources of lead toxicity in birds are listed in the table below. Read through the list and check that your pets are protected.
SOURCES OF LEAD Toxicity in birds
Lead fishing weights, , Lead gunshot, Lead putty, Lead solder
Lead based paints – especially undercoats in older houses -paint pigments.
Glitter from trendy clothes, Christmas ornaments
Foil from the top of wine and champagne bottles
Pewter based products
Stained glass window
Coins, Costume jewellery
Light bulb bases
Zinc is a trace element necessary in the diet and can cause problems if the diet is deficient in this trace mineral. So both toxicities and deficiencies can exist.
Zinc toxicity, also known as New Wire Disease, is a common syndrome that is under diagnosed. Aviary wire is galvanized with zinc oxide to protect it from the elements. Often the brighter and more shiny the wire the higher the zinc content. There are many household products that also contain zinc as a component. Clinical signs are similar to those seen in lead poisoning.
Sources of Zinc toxicity in birds
Galvanized wire aviaries
Galvanized nails, mesh, washers
Monopoly game pieces
Diagnosis - The heavy metal poisoning in birds can be difficult to confirm and monitor, we often need a combination of tests, including x-rays, repeated lab results and clinical signs, to confirm and provide appropriate therapy. We start with:
1) Discuss the bird’s environment with the owner – especially concerning cage material, toys, and cage enclosure age - exposure of bird to toxins and a discussion of the birds’ environment.
2) On physical examination we may find – regurgitation or vomiting, watery green or bloody droppings, weakness, and fitting.
3) Radiographs / x-rays – we may see the heavy metal particles in the bird usually in the crop, gizzard or elsewhere in the gastro intestinal tract,
4) Changes in blood enzyme levels to reflect damage to organs and red blood cells.
5) High Blood Lead levels are diagnostic; repeating blood lead levels once on treatments allows us to monitor the recovery
Treatments for Heavy Metal toxicity in birds include:
1) Fluid therapy to protect the organs from further damage and to flush the toxins out the body.
2) A metal cheating agent, calcium EDTA – works by “trapping” the lead or zinc into its central ring and then filtering it out the kidneys, or into the intestine. The drug is injected twice daily till improvement starts. Oral D-penacillamine is can also be used as an oral medication.
3) Antibiotics are given to prevent infections while the body is recovering.
4) Crop feeding - to add fluids and calories necessary for recovery.
5) Vitamin B complex and especially thiamine to prevent deposition of metal into tissues and help the nerves recover.
6) Place avian patient in an incubator in a quiet low stress environment so all of the bird’s energy can be used for recovery.
7) Treatment of seizures with anticonvulsants.
8) Large metal pieces may be removed under general aesthesia or if possible allowed to pass naturally.
9) Smaller metal pieces not passing through can be flushed under general anaesthetic using warm fluids.
10) Bulking agents can be added to the diet or crop fed to hasten the removal of metal particles through the gastrointestinal system.
A large zinc particle ingested – now lodged in the gizzard of a parrot. (Birdvet Melbourne)
Prevention of metal poisoning in birds
1) Avoid sources of lead and zinc and copper.
2) Stainless steel cages and toys and food containers are safe.
3) Scrubbing the new cage / wire with a wire brush and vinegar
4) Read through the tables in the article and familiarize yourself with some of the many potential sources of toxic metals.
5) Avoid your pet access to objects that are potentially life threatening.
Harold an 8-year-old male Pekin Duck presented with water droppings containing fresh blood, a wing droop and tail deviated to the left. His owners absolutely adored him and were determined to get him better.
Note the wing droop and abnormal stance, and also the hospital environment – supportive soft bedding, large water dishes, varied diet. Harold’s was quiet. (Duck -Bird vet Melbourne)
Note the red watery droppings that may be seen in lead poisoning cases. (Duck Bird vet Melbourne)
Note the multiple metal densities present in the gizzard. and also one in the cloaca. (x-ray, chicken, Poultry vet Melbourne)
Treatments for Harold:
1) Fluid therapy
3) Metal trapping with inject able Calcium EDTA and oral D-D-penacillamine
4) Bulk laxatives
5) Crop feeding
We repeated the x-rays in 2 weeks and most of the metal densities had passed so surgery was not necessary, the blood in the droppings gradually cleared and Harold has made a good recovery.
While expensive, stainless steel is the safest option for aviary wire. A local Melbourne source is: