What are Bornavirus?

Researchers have found a link between the onset of Proventricular Dilatation Disease, or PDD, and Avian Bornavirus. PDD can cause the infected bird’s immune system to become over-responsive. This will cause damage to the digestive system. The most common problem with PDD is that it causes intestinal paralysis, resulting in food becoming stuck in your bird’s proventriculus. The intestine will swell, causing great pain for your bird. Death will occur when your bird is unable to absorb the nutrients from the food that has become stuck.

Birds that are infected with ABV may not show any symptoms of PPD for several years or even decades. They can be carriers of the disease without presenting any symptoms. Since they are carriers, they can still infect other birds with ABV and PPD.  

PDD was originally referred to as Macaw Wasting Disease since it was first diagnosed in macaws. But it is commonly found in parrots, lovebirds, Quaker parakeets, finches, cockatiels, geese and mute swans.

Avian Bornavirus, or ABV, is also known as Borna Disease. ABV will attack the nervous system and can be fatal. Borna Disease was detected in wild birds in 2000. In 2008 it was found in domesticated parrots and was officially renamed avian bornavirus. ABV is transferred when a bird comes into close contact with an infected bird. Coming into contact with an infected bird’s feces can also cause the virus to be spread.

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Symptoms of Bornavirus in Birds

By being a proactive bird owner and regularly assessing your bird’s health and behavior, you can determine quickly if your bird is suffering from an ailment. When you notice something is off or wrong with your bird, contact your veterinarian for an appointment and have your bird thoroughly examined. Symptoms of ABV and PDD to watch for include:

  • Weight loss despite still maintaining a good appetite
  • Passage of undigested food in their feces
  • Abdominal distention
  • Vomiting
  • Impaction of the crop and proventriculus
  • Intermittent shaking of their head
  • Plucking out their feathers and other forms of self-mutilation
  • Balance problems
  • Crying or moaning 
  • Behavioral changes such as aggression
  • Seizures

Causes of Bornavirus in Birds

Avian Bornavirus is a negative stranded neurotropic RNA virus. This means that the virus can infect nerve cells and is classified with other diseases such as Poliovirus, Herpes virus and Rabies.

Research is relatively new in regards to ABV and PDD, therefore the cause is still not fully understood. It is thought to be transferred from direct contact with an infected bird or an infected bird’s feces. Researchers are working on the development of a preventative vaccine for ABV and PDD.

Diagnosis of Bornavirus in Birds

Your veterinarian will conduct a thorough physical examination of your bird and speak with you regarding when the symptoms appeared and your bird’s medical history. There are two commonly used methods for identifying ABV. Your veterinarian may order both testing panels to be completed, or they may feel that only one is sufficient.

ABV rELISA will test for immunological exposure to ABV specific antigens. This panel consists of four ABV specific proteins and only a small serum sample is required to perform the test.

ABV rtPCR will detect the presence of ABV specific RNA. This panel is a multiplex assay that will examine the genes of your bird. The chest or breast contour feathers of your bird produce the most reliable samples. Blood is not recommended as a reliable sample for this test.

It is not recommended to do fecal samples or cloacal swabs to conduct routine screening for ABV.

Postmortem detection, or testing after your bird has died, is usually done by taking samples from the brain, proventricular tissue or crop. Samples should be stored in alcohol prior to the biopsy being performed.

Treatment of Bornavirus in Birds

Once ABV or PDD has been confirmed, your veterinarian will discuss treatment options with you. There are no known treatments for ABV or PDD; however, your veterinarian may discuss with you the option of trying experimental treatments that include combining cytokines and antiviral drugs.

As the disease progresses, your bird will need supportive care including fluid and nutritional therapy. Your bird will require specialized care as the disease progresses. In some cases the disease progresses quickly, causing death to occur at a faster rate. Researchers are currently working on a vaccine that will help treat ABV and PDD. However, this research is still in the development phase.

Recovery of Bornavirus in Birds

Since there are no known treatments for ABV or PDD, the prognosis for your bird is grave. Your veterinarian will be able to give you a more accurate prognosis based on your bird’s test results and their overall health.

There are several birds that are carriers of ABV and they will never show symptoms. It is important to keep your bird from fraternizing unnecessarily with birds that are unknown to you. Regular screenings for ABV and PDD will help keep your bird healthy and provide the necessary care quicker so they can live a longer life.