PDD: the killer of parrots which is difficult to fight against

March 12th, 2015 | by LubosTomiska
PDD: the killer of parrots which is difficult to fight against

VIDEO IN – PBFD and psittacosis represent the best known diseases of parrots. However, PDD (Proventricual Dilatation Disease) is no less common and dangerous. It was firstly described in 1970 as the Macaw Wasting Syndrom. The cure is always very difficult and it can be tricky to recognize an affected bird. Veterinary doctor needs a sample of the stomach mucous membrane or the crop musculature.

What are the symptoms?

The only possibility how to get the sample from a living bird is a crop biopsy. Unfortunately, such invasive intervention can lead to postoperative complications. PDD is caused by avian Bornavirus so it’s viral disease which can be infectious and viral particles are spread in the air. Transmission can for example occurs when birds are feeding mutually. Incubation takes one week but can be prolonged to two years as well. The disease is lethal for birds younger than 2 years. Older individuals are mostly transmitters. Virus can affect digestive and nervous system. The bird accepting the same dosage of the food as usual is asking for more and wastes evidently. It’s apathetic and we can see undigested seeds in feces.

Unfortunately, you will find out this disease firstly when the bird is already apathetic. Consequently, it’s necessary to take a sample of the stomach mucous membrane and make the histological examination. Condition of such bird can change fast so you have beautiful strong bird and suddenly it dies. There are many diseases which can’t be solved preventively,“ Dr Markéta Hašlová from Veterinární klinika Trnová explained. PDD doesn’t affect only macaws. It was just firstly described on this group of parrots. Up to now we know about more than 50 parrot species which are sensitive to PDD. Unfortunately, the affected individuals die in most cases.


File:Ara ambigua - Ara zeleny Zoo Hodonin.jpg

Macaws represent the most frequently affected parrots by PDD. Photo: Buffon’s Macaw. (c) Bohuna Mikulicová. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.


Some infected birds are only transmitters

The disease doesn’t have to develop in all cases (mostly in birds older than 2 years). It’s not easy to prove infection of such individual. Firstly, it has to be tested on Bornavirus and then the stomach mucousa examination is necessary. The second step will prove or falsify the results of the first test. Complications arise when there is no suspicion of this disease. Then infected parrots look helathy and can spread the virus among other birds. Don’t forget about possible transmission between a parent and its baby. If your parrots were provably infected by PDD then you have to immediately test the rest of your collection. Such birds should never breed as already mentioned, youngs can be infected from their parents. Secondly, nesting is costly for a breeding pair and takes lot of energy which can be dangerous for infected birds. It’s necessary to keep strict quarantine in your facility. Selling of individuals with positive PDD tests is not recommended even though they can look healthy.



 Title photo: wiki commons, © johnrosner


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