Downloadable PDD medical facts written by Dr. Susan Clubb

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Originally found in the late 1970's, PDD is also known as macaw wasting disease and neuropathic gastric dilatation disease.PDD causes an inflammatory response in the nervous system, especially those nerves supplying the gastrointestinal tract. As the disease progresses, it can cause malabsorption of nutrients, which means despite a ravenous appetite the bird's body is unable to digest food properly. This causes severe weight loss, and ultimately death. Some known signs that may or may not occur include depression, weight loss, regurgitation, and neurological disorder. Sometimes the passage of undigested seed is also seen. Any combination of several symptoms or absolutely none may be seen.

It's the potential lack of symptoms that we find so frightening about this disease. Very few birds in our care have shown signs of illness. One died within two weeks of diagnosis. Another had had neurological signs for some time before succumbing. The most recent bird to leave us was never diagnosed. The rest are the picture of health.
PDD is contagious, although all routes of transmission are not clear. It is believed to be transmitted through contact with crop contents and fecal matter. It is not believed to be airborne, but this is not guaranteed. PDD may be diagnosed through a crop biopsy, although a false negative may occur. For this reason, the pathologists we send our tissues to do not report a negative. It is not detected, suspicious or positive. The only guaranteed result is a positive. If a not detected bird is clinically normal, we either re-biopsy or continue to monitor for changes. If a suspicious bird shows clinical signs and exposure is confirmed, we treat them.

It has been common practice to euthanize infected birds to minimize the risk of transmission. We hope to one day put an end to this through work with dedicated vets and researchers. Recent follow-up test results have given us reason to be cautiously optimistic about our treatment program.

WHAT WE ARE DOING ABOUT PDD

In January 2003 we changed our focus from accepting any unwanted bird to launching a PDD study, research and treatment program with our vet, Dr. Susan Clubb. At this time we are only taking in birds with confirmed infection, or ones who have been deemed suspicious enough by Dr. Clubb to warrant treatment.
All birds must undergo a crop biopsy +or- radiographs, endoscopy and blood work to confirm infection. Infected birds are housed outdoors (except for a few that cannot go out for various reasons) where the virus is subjected to sunshine and fresh air, which is believed to kill the unstable virus. It is only unstable outside of its host. We do not pressure clean any of the aviaries, due to the threat of aerosolization of the virus.
We currently have our birds split into 4 groups, 2 positive on different non-steroid anti-inflammatory drugs, 1 suspicious for infection, on treatment. The forth group consists of birds whose biopsy results were "not detected". This does not mean negative just that the inflammation indicative of PDD was not present or the test, not being 100% except where found to be positive, was not able to detect infection. Although the results do not guarantee lack of infection, the latter group is not currently being treated because their exposure is uncertain, they are not showing potential signs and it is not considered safe to treat without confirmation.
Groups 1 and 2 (positive) and group 3 (suspicious) receive daily treatment and are watched closely for changes in appetite and demeanor or any other signs that may indicate a problem. After their first year of treatment, group 1 had follow-up biopsies. The results breakdown:
6 NOT DETECTED - again this does not necessarily mean negative, only that the pathologist was unable to detect inflammation in the tissue. Although the results are great news, we are only very cautiously optimistic about our success and effectiveness of treatment
1 SUSPICIOUS - this means inflammation was present, but not enough to be considered positive.
2 INSUFFICIENT - this means there were not enough ganglia (nerve cell body) to make a diagnosis, and other sections of tissue must be cut.
Group 2, which is considerably larger than group 1, will undergo biopsy surgery in March 04, following 6 months of treatment. This will help determine if 6-month treatment is sufficient to detect changes and whether the drug they were treated with has the same effect as the drug used for group 1.
If results do not show a high percentage of improvement, we may consider switching them to the same drug group 1 is receiving. This will be determined through consultation with our veterinarian.
Groups 3 & 4 will be re-biopsied after the proven positives have been completed.
All groups will continue treatment and/or monitoring. Whether or not long-term treatment is necessary remains to be seen. We are prepared to continue this study as long as needed. Until a proven cure is found we will be committed to the optimal care and treatment of infected birds at our facility.

WHAT YOU CAN DO TO HELP US FIGHT PDD
It is more important now than ever before to provide our bird with quality of life and a healthy diet. If you're local, you can help by volunteering your time. If not you can make a monetary donation, donate species appropriate food, or specific anti-inflammatory drugs and other supplies. If you would like to help us you may also contact us for a list of other needed supplies at support@milosranch.org.