Diagnosing diseases that target certain pet bird species (Proceedings)
Proventricular Dilatation Disease (Macaws, Conures, others)
This presentation focuses on a disease proventricular dilatation disease (PDD) that many people have heard about, may have had bird's affected, but know little about. The same may be said for veterinarians. It is especially frustrating for the veterinary community to know enough to diagnose a disease but have no means of prevention or treatment against the organism responsible. This is because we do not know what organism is responsible. This is evidence that a virus is the cause of the disease but its identification is still elusive. A short history of PDD shows that it was first identified in the late 1970's associated with imported psittacine species in the U.S. and Europe. A number of avian species have been identified as being susceptible to PDD including over 50 psittacine species. Common pet birds in which PDD has been diagnosed include, African grey parrots, cockatiels, conures, lovebirds, Amazon parrots, cockatoos, eclectus parrots and macaws.1 No reports of the disease have been documented in wild psittacine birds living in their native environment but it does not appear that they would free from contracting PDD. PDD has been diagnosed in birds ranging in age from 10 weeks to 17 years with the average age of infection being 4-5 years.1 Another major problem with PDD is that it can invade the best of aviaries because of its random occurrence and potentially long incubation time. An infected African Grey parrot had no direct contact with other birds for 4 years. We have had young cockatoo's, less than 6 months old, develop clinical neurologic signs (e.g., twisted head, vocalization, unable to perch) and die within 2 to 3 weeks. The medical community does not know what causes the disease or how long the incubation period is before signs are observed. We know that it may can be a very fast disease in young birds and very slow in older birds with many variations. Owners may notice PDD birds lose body condition despite a very good appetite, delayed crop emptying, neurologic signs as mentioned before and passing undigested food in the feces. If a bird has one or more of these signs how is a definitive diagnosis obtained? A radiographic image of an enlarged proventriculus is not definitive for proventricular dilatation disease. A veterinarian must take a biopsy of the crop, including a blood vessel in the biopsy sample, for a definitive diagnosis. This does not always determine if the bird is suffering from PDD. A biopsy of the adrenal gland has also been advocated as an option for diagnosing PDD. Once diagnosed, every case is different in options, and these should be discussed with your veterinarian. In older birds with less severe disease conditions supportive care, including the use of anti-inflammatory therapeutic medication (Celecoxib, Celebrex®), has shown promise in treating PDD patients.
Proventricular dilation disease is a serious disease, not necessarily because of what we know, but what we do not know. We do not know if in fact it is caused by an infectious agent (highly suspect), if it is a slow progressive disease, if there is a long incubation period, if infectious how is it transmitted or preventive measures. All we can do as veterinarians is to inform bird owners what we know and review each case as they are diagnosed. Bird owners can try and maintain good aviculture management and bird health oversight. As I have stated this does not guarantee that PDD will not strike your birds but it sure will help reduce the odds of major disease outbreaks over and above the subject of this article.Feather Picking (African Grey Parrots, Amazon Parrots, Macaws, others)
Self-induced feather loss in companion birds is one of the most common and frustrating avian case presentations. There are a number of causes for feather loss and these cases require a thorough investigative work-up by the attending veterinarian. Differential diagnoses for feather picking birds include hypersensitivity, environmental and nutritional causes and psychological.
Initial treatment is based on history, clinical presentation and diagnostic test results. If a disease process is identified as a primary cause of the feather loss then it is appropriately treated. If it is determined that the self-induced feather loss is psychological the other medications are prescribed. We start with the anti-depressant and hope that treatment is effective. If we decide that the bird should be treated with the anti-psychotic medication we have a conference with the owner explaining the serious side affects that may be noted with its use. We never place a patient on a concurrent anti-depressant and anti-psychotic treatment regime.