***IMPORTANT NOTICE 6/4/2018*** - Unfortunately Birdline are now full with regard to rescue birds, and are currently UNABLE take additional birds into the charity. We will provide an update as soon as the position changes

WARNING – Please Be Aware 

If you are looking to re-home your parrot, please always use a reputable Parrot Rescue Organisation.

Always check to ensure the organisation you wish to use is registered with an approved organisation such as ‘The Charities Commission’ 

Please note that we only operate in England, Scotland and Wales. Birds going to be re-homed or safe housed must stay in one of these three countries 

   Proventricular Dilatation Disease (PDD)  

Kevin Eatwell BVSc (hons) DZooMed (Reptilian) MRCVS
RCVS Recognised specialist in Zoo and Wildlife Medicine
Exotic animal and Wildlife Service
Hospital for Small Animals
Royal (Dick) School of Veterinary Studies
EH25 9RG

Proventricular dilatation disease is a chronic illness in parrots. It is believed to be caused by a virus (there are a number of suggested agents) and it is a difficult condition to diagnose. It is believed that birds are infected by ingesting the virus. This then causes inflammation in the nerve supply to the digestive tract and occasionally the central nervous system leading to the clinical signs. Muscle wasting of the digestive tract reduces the birds ability to digest and absorb food.

Clinical signs can include anorexia, wasting, nervous signs, regurgitation and passing of whole seeds. When the bird is examined the abdomen may feel doughy or quite full. The severity of infection varies between species. Grey parrots, macaws and cockatoos are frequently clinically affected whereas Amazon parrots survive for much longer periods and can show minimal signs.  Birds as young as 10 weeks to 17 years of age can be showing clinical signs.

It can take up to seven years for these clinical signs to become evident and as a result it is very hard to ensure a collection or your pet bird is free from the disease. When getting a new bird examined if it is carrying the infection but not showing signs it is highly likely that this will go undetected.

The diagnosis of a case can be complicated. Clinical signs and radiography may be sufficient for a suggested diagnosis and giving the bird some barium under anaesthesia can help to outline the intestines. Typically the birds proventriculus is distended but occasionally the small intestine can be involved as well. However for confirmation a surgical crop biopsy can be taken. For this a small section of the crop is taken and sent to the laboratory for histology. The infection leads to a characteristic pattern of inflammation. However a crop biopsy may miss up to 24% of cases as the disease can be quite restricted in the gastrointestinal tract. This presents difficulties when wishing to screen for this condition and prevent it from entering a collection. Biopsy of other organs increases the surgical risk and is generally not performed. Many cases are based on a presumptive diagnosis with possibly a positive crop biopsy.

Treatment can help to control the condition. Specific types of anti-inflammatory drugs can be used to reduce the inflammation around the nerves. Celecoxib a human drug is typically used and has been shown to lead to regression of the signs of PDD. Improving the digestibility of the diet by feeding the bird a pelleted diet can also help it to maintain bodyweight.

Post mortem examination of diseased cases is usually fairly typical with a distended J shaped proventriculus that is thin walled and packed with food. Histopathology of the bowel and nervous system should be taken to confirm the condition.

For control then there are two options to consider. Screening is not helpful given the number of false negatives. Quarantine is important but to be completely sure the birds are disease free this may need to be for a number of years. It is possible to do this and house new birds in a separate facility where they can breed. Any birds that die during the quarantine should undergo a post mortem examination to check if PDD is present. Such a lengthy quarantine can be problematic for many individuals and another option is to source birds from collections which are free of the condition. The only way to confirm this is through checking the collections history. Confirming that all birds that have died were negative for this condition and that any new introductions were from collections with a similar history is required. To be completely sure the last seven years of records should be considered. The difficulty is finding a collection where their status can be reasonably guaranteed.

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