Psittacosis or "Parrot Fever" is a form of the Chlamydia bacterium that can affect all hookbills. The disease is highly contagious and can be passed from birds to other animals, including humans. Symptoms of Psittacosis include difficulty in breathing, eye infections and inflammation, loose, watery droppings, and general lethargy.
PDD (Proventricular Dilatation Disease) is one of the most troubling bird diseases. The ways that PDD is spread from bird to bird are still unknown. Symptoms of PDD include weight loss, vomiting, changes in the bird's droppings, and a swollen crop. PDD is also known as Macaw Wasting Syndrome or Parrot Wasting Syndrome.