Hepatitis - Birds
Hepatitis refers to inflammation of the liver which can lead to gross lesions visible at necropsy.
In birds, these lesions are seldom diagnostic, as numerous infectious diseases cause hepatitis. Liver inflammation usually occurs alongside systemic infection and changes in other organs such as the spleen and lungs may be helpful in obtaining a diagnosis.
Histopathology can usually be more revealing, especially if special stains are used. Electron microscopy, viral isolation, DNA probes and special cultures can be used to get an exact aetiological diagnosis.
Most causes of hepatitis are difficult to diagnose in the live bird, unless the enlarged liver causes abdominal distension or biochemical tests produce significant results.
Common causes of hepatitis are as follows:
- Pacheco's disease caused by a herpesvirus
- Avian polyomavirus
- Acute Psittacine Beak and Feather Disease
- Adenovirus inclusion body hepatitis
- Reovirus-associated hepatitis
Columbiformes, Strigiformes and others
Anseriformes Goose Virus Hepatitis
Galliformes Mareks Disease
Gram-positive and gram-negative bacteria can cause liver disease, usually secondary to septicaemia or enteritis.
Staphylococcus and Streptococcus species are the most common organisms isolated. They disseminate through the blood from chronic necrotising skin lesions or can reach the liver by extension from adjacent air sacs.
Clostridia are of intestinal origin and can cause hepatitis.
Listeria monocytogenes can also cause disease, although it is a rare pathogen of birds.
These are the most common causes of systemic bacterial infection.
This is usually secondary to invasion from the gut or extension up the biliary tree.
M. avium infects all birds.
Chlamydophila psittaci causes psittacosis and hepatomegaly with yellow foci of necrosis.
This is usually from extension from the lungs or air sacs, or as a result of haematologic spread.
Aspergillus species most commonly affect the liver.
Systemic Candida infection, particularly in immunosuppressed birds, can also result in liver invasion.
Microspora: Encephalitozoon hellem
Ingestion of heavy metals such as lead or zinc.
Vitamin D toxicity
Mycotoxins such as Aflatoxins
Chronic-active hepatitis, or cirrhosis, is common in psittacine birds, particularly parrots, cockatiels, mackaws and budgerigars. The cause of the hepatitis cannot be determined due to the chronicity of the lesions.
|Hepatitis - Birds Learning Resources|
Test your knowledge using flashcard type questions
|Avian Medicine Q&A 11|
Samour, J. (2000) Avian Medicine Elsevier Health Sciences
Schmidt, R. (2003) Pathology of pet and aviary birds Wiley-Blackwell
Doneley, R. (2010) Avian medicine and surgery in practice Manson Publishing
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