Diseases of Pet Birds

Pacheco's disease (PVD) or parrot herpes virus is a viral disease which was thought to attack only birds of the Psittacines family. However there are isolated instances of other birds contracting the disease. PVD causes acute viral hepatitis. It was first seen in the 1930s. New World parrots (those from the Americas) seem more susceptible than Old World parrots from Australasia and Africa.

The virus is transmitted by contact with contaminated items such as water, food or faeces. Inhalation of the virus is also possible but less common. Ill birds shed the virus in large numbers in secretions from the eye and nasal passages, and through faeces. A bird may not show any symptoms of the disease but may be a carrier. Some bird species appear to have a resistance to the disease but are commonly carriers. Examples of such species include Mitred, Nanday and Patagonian conures.

Eclectus ParrotCredit: Wikimedia

In addition, any bird that has recovered from Pacheco's disease will be a carrier. Any stress such as environmental changes, loss of mate or relocation, is enough to reactivate the virus which is then shed in the faeces. The disease is highly contagious and quick action needs to be taken to avert the spread of the virus once it has a hold in an aviary.

Little warning is given that a bird has Pacheco's disease. Death occurs suddenly. There may be diarrhoea followed by death within 48 hours. Regurgitation, a ruffled appearance, tremors (particularly in the wings, legs and neck), seizures, conjunctivitis, yellow-green diarrhoea and imbalance may all indicate the illness. A post mortem will reveal enlargement of the kidneys, liver and spleen. There may be necrosis on the liver and internal haemorrhage of the spleen, pancrease and intestines. The incubation period is 3 to 7 days after infection. The lymphatic tissue, skin and nerve cells are most affected.

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Because of the sudden onset and rapid death, treatment is difficult. Acyclovir is often given supported by administration of fluid intravenously and tube feeding. Infected birds should be isolated. Acyclovir is an antiviral drug but sometimes causes kidney damage. Prevention is much the best option. Any birds coming out of quarantine or in quarantine, those housed in large groups in aviaries and pet stores, and imported birds should be considered at risk. All new birds should be quarantined for 30 to 60 day and birds exposed to PDV should be isolated. PCR testing will determine if birds are infected.

Prevention should include thoroughly disinfecting the environment and items within it, such as food bowls, perches and nesting boxes. Use an oxidizer such as chlorine bleach as alcohol will not be effective. Replace all air filters and clean vents and fan blades with a strong disinfectant. There is a vaccine available against the disease but there are occasional adverse reactions and it seems some strains of PDV are resistant to the vaccine. It is best to vaccinate only those birds that seem to be at high risk of contracting PDV.

As always, good hygiene practices will help avert this horrible disease.