What is Macaw Wasting Disease?

Macaw wasting disease in birds was first documented forty-five years ago, as veterinarians noticed this disease, also known as proventricular dilation disease, or PDD, was affecting Macaws as they gradually “wasted away”.  The birds affected were those which were imported from Germany into the United States. Over 50 species of birds, namely pet birds, can be affected by this disease. Within the types of birds affected, approximately twenty to thirty percent of birds can be affected.

The proventriculus is the narrow section that is between the crop and the gizzard. The proventriculus is also known as the true stomach.  With this disease, the nerves that aid the muscles of the true stomach, or proventriculus, and other digestive system parts are affected. This causes the food the bird consumes to not flow through the digestive system normally. Nutrients are unable to be absorbed properly. The nerves which supply other organs of the birds can also become affected. Inflammation of the brain, known as encephalitis, can also occur.

Macaw wasting disease in birds, otherwise known as Avian bornavirus/proventricular dilatation disease, is a condition which impacts the nervous system and digestive tract of birds.

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Symptoms of Macaw Wasting Disease in Birds

Symptoms of PDD can be quite severe. Birds affected can have various symptoms, or all of the following symptoms. They include:

  • Weight loss
  • Undigested food which is passed
  • Regurgitation
  • Tremors
  • Convulsions
  • Weakness
  • Ataxia
  • Blindness
  • Gastrointestinal upset or irritation

Types

There are several types of birds in which Macaw wasting disease is more commonly found. It is important to be aware of the symptoms of this condition if you have one of these types of avian companions. Types include:

  • African Grey parrots
  • Amazon parrots
  • Cockatoos
  • Conures
  • Macaws

Causes of Macaw Wasting Disease in Birds

Macaw wasting disease may be related to avian bornavirus, and birds exposed to this virus may become affected. Causes may include:

  • Affected nerves become inflamed with white blood cells
  • Muscles of the stomach are affected
  • Digestion is impaired
  • Virus is susceptible to heat, disinfectants, and dryness
  • Directly comes from oral fecal contamination 
  • Virus is airborne

Diagnosis of Macaw Wasting Disease in Birds

If your bird is showing signs of proventricular dilatation disease, make an appointment with your veterinarian. Your veterinarian will then take blood work, urinalysis, and a biochemistry profile. There are several different tests that are conducted to test for PDD, and some can be quite complicated. 

Your veterinarian may perform a test using barium called contrast radiography. This test will show an enlarged and inflamed proventriculus and a typical ventriculus. There are also other tests that can be performed such as blood tests for avian bornavirus, and there may be a chance that it caused your bird’s condition.  A polymerase chain reaction test may also be performed by way of choanal (whole, unclotted blood) samples, cloacal swabs, or fecal swabs. This will confirm if your bird has ABV. A serologic assay can also confirm the presence of the disease.

Your veterinarian may perform additional laboratory testing to also rule out any differential diagnoses. Differential diagnoses may be a heavy metal toxicity, and intestinal obstruction from a foreign body, internal neoplasia, and any gastrointestinal infection or inflammation.

Treatment of Macaw Wasting Disease in Birds

If your bird is diagnosed with PDD, your veterinarian will give you a specific treatment plan to help him recover. Unfortunately, there is no definite treatment of this disease, and many birds do succumb to the illness. There are ways, however, to minimize his symptoms and, hopefully, help him heal. Treatment methods may include:

Dietary Changes

Your veterinarian may recommend dietary changes for your bird. Introducing foods that are very easily digested can help. Your veterinarian will recommend a diet for your avian companion.

Isolation

If your bird is affected by PDD, he will need to be isolated for a little while. This disease does not live long in the environment, but it is very important that affected birds are kept away from the healthy birds.

Living Condition Changes

A clean environment with good hygiene is important to prohibit the disease from spreading within the home. Also, an ultraviolet light can help limit the spread of this disease.

Medications

Your veterinarian may recommend an anti-inflammatory medication such as meloxicam or celecoxib. These NSAIDS can help your bird adjust to the new diet and decrease any inflammation and pain your bird may be suffering from.

Recovery of Macaw Wasting Disease in Birds

Your veterinarian will explain to you the importance of monitoring your bird and giving supportive care to him. He will discuss with you how to treat any secondary infections or diseases and how to feed him properly. Unfortunately, this condition is typically fatal. Continuing to care for your bird at home, as long as he is isolated, may be an option for you. Some owners decide to consider humane euthanization in birds that are severely impacted by this grave disease. 

Your veterinarian will discuss your options with you and can give you advice on what to do in terms of caring for your bird at home. It is very important that this virus is not spread to any other birds, as they may face the same fate.