Overview
Proventricular Dilitation Disease (PDD) is a neurological disease cause by Avian Bornavirus. One of the characteristic syndromes is dilation of the proventriculus, ventriculus and intestines resulting in maldigestion.
Signalment
PDD has been diagnosed in over 50 psittacine (parrot) species as well as canaries, honeycreepers, weaver finches, waterfowl, toucans, and birds of prey. Sexes are affected equally. All ages are affected.
Signs
- Weight loss, muscle wasting, emaciation
- Dilation of the proventriculus and/or ventriculus
- Vomiting, diarrhea, undigested seeds in stools
- Central nervous system disorders, seizures, incoordination, blindness, abnormal headmovements
- Polyuria (increased urine output)
- Cardiac abnormalities
Causes
- Avian Bornavirus (ABV)
- There are 10 known genotypes of ABV and 7 of these are known to affect psittacine birds. The virulence of these genotypes can vary. There is also evidence that an asymptomatic bird harboring one genotype can sometimes become ill after exposure to a second novel genotype.
- There seems to be an unidentified triggering mechanism which can cause clinical expression of ABV infection.Risk Factors
- Exposure to infected birds shedding the virus in urine and feces
- Indoor housing with other infected birds
- Birds infected at a young age may have increased risk
TreatmentAppropriate Health Care
- Highly digestible diet
- Nutritional anti-oxidants
Activity
- Activity should not be limited if the patient is physically capable.
Diet
- The diet should be highly digestible and preferably contain higher than normal fiber foods to aid in intestinal motility.
- Birds on a seed diet may have more difficulty digesting foods. Conversion to a formulated diet may be very difficult in an ill bird. Supplemental feeding of highly digestible foods will be beneficial.
- Supplementation with foods high in anti-oxidants may help reduce inflammation.
Medications
- Non-steroidal anti-inflammatory drugs such as celecoxib, meloxicam, or robenacoxib can reduce and or reverse inflammatory cell infiltration into neurons.
- Metoclopramide to assist with intestinal motility. Follow-Up
Patient Monitoring
- Body weight as well as food types and consumption should be monitored at home. Weight gains can be misleading if the intestinal tract becomes dilated and filled with ingesta.
- Owners should be aware of signs which may indicate secondary infections, especially with spore-forming bacterial infections or yeast due to prolonged intestinal transit times.
- If treating with NSAIDS, feces should be monitored for blood which may indicate proventricular ulceration.
- Monitor dilation of the proventriculus by periodic X-rays. Possible Complications
- Foreign body ingestion
Expected Course and Prognosis
- ABV infection does not equate to clinical PDD. Many birds test positive for avian borna virus without having “PDD.”
- Birds which test positive for ABV may not develop clinical disease for years, or may never develop clinical PDD.
- There is a poor prognosis for birds exhibiting severe clinical illness.
Key Points
- Proventricular dilatation disease is caused by avian bornavirus
- Signs can vary and may include gastrointestinal signs, neurologic signs, and others
- ABV does not equate to clinical proventricular dilation disease
- Some medications, while not curative, can help lessen signs
- Infected birds are ideally segregated from non-infected birds to lessen the potential fordisease transmission
- Adapted from Avian Five Minute Consult (Graham)