Todayโs path rounds are on ๐ฅ๐๐๐ ๐ญ๐จ๐ฑ๐ข๐๐ข๐ญ๐ฒ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐๐๐ ๐ญ๐จ๐ฑ๐ข๐๐ข๐ญ๐ฒ is exactly what the name suggests, toxicity from ingesting too much lead. There are several potential causes of this condition across species, but today we are going to talk about birds!
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
We most commonly see this condition in ๐ฐ๐๐ญ๐๐ซ๐๐จ๐ฐ๐ฅ, like geese and ducks.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
The most common cause of lead toxicity in waterfowl is ingesting ๐ฅ๐๐๐ ๐๐ฆ๐ฆ๐ฎ๐ง๐ข๐ญ๐ข๐จ๐ง, particularly shot pellets. The lead shot looks like a tasty treat to a hungry bird, causing them to eat the pellets. Unfortunately for the bird, lead is a very soft metal, and is quickly absorbed via the gastrointestinal tract.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Lead is directly toxic to several tissues, including the immune system, brain and nervous tissue, red blood cells, the heart and the kidneys. In birds, toxicity most commonly causes ๐ฉ๐ซ๐จ๐ฏ๐๐ง๐ญ๐ซ๐ข๐๐ฎ๐ฅ๐๐ซ ๐ข๐ฆ๐ฉ๐๐๐ญ๐ข๐จ๐ง. The proventriculus is more commonly known as the โcropโ, and is basically an outpouching of the esophagus that is used to grind up feed before it reaches the stomach. Lead toxicity prevents the nerves normally involved in esophageal movement from firing, causing accumulation of food in the crop. Another common finding is ๐ก๐ฒ๐๐ซ๐จ๐ฉ๐๐ซ๐ข๐๐๐ซ๐๐ข๐ฎ๐ฆ, or accumulation of fluid in the sac that surrounds the heart. This is likely due to heart failure from the toxinโs effects on muscle.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Diagnosis is typically based on ๐ญ๐จ๐ฑ๐ข๐๐จ๐ฅ๐จ๐ ๐ฒ ๐ฉ๐๐ง๐๐ฅ findings, where a piece of liver from an animal is submitted to test for lead concentrations. In some cases, it can also be diagnosed by looking at the tissue under the microscope. Lead produces characteristic ๐ข๐ง๐๐ฅ๐ฎ๐ฌ๐ข๐จ๐ง ๐๐จ๐๐ข๐๐ฌ within many types of cells, however we most commonly see them in the kidney.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐? ๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ฉ๐ซ๐๐ฏ๐๐ง๐ญ๐๐?
Unfortunately, treatment for wild bird species is often impractical, since it would involve extensive hospitalization of each affected bird. So, prevention is very important! Many countries have restricted lead ammunition in waterfowl areas, to prevent loose shot from being accessible to the birds.
๐๐ก๐จ๐ญ๐จ๐ฌ
1) An X-ray of a swan showing a bunch of lead shot in its crop.
2) What the lead shot looks like! Tasty (if youโre a bird 
)!
3) A very enlarged crop due to lead toxicity.
4) Hydropericardium from lead toxicity.
5) What the inclusion bodies from lead look like under the microscope!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Terio, KA, McAloose, D, St. Leger, J. Pathology of Wildlife and Zoo Animals. 2018.
Photos 1-2 ยฉ Wikimedia Commons contributors Lamiot licensed under CC Share Alike 2.0 Generic.
Photos 1-5 ยฉ Noahโs Arkive contributors Leighton, Reece licensed under CC BY-SA 4.0.
