Introduction

A viral disease of ducks occurring worldwide and previously a scheduled disease in UK. Morbidity is around 100% and mortality 0-95%.

The disease is transmitted by infected ducks and other waterfowl and spreads rapidly, recovered birds carrying the virus for 8 weeks. The infective agent, a picornavirus may also survive for ten weeks in brooders and five weeks in faeces. A different picornavirus causes a similar condition in North America.

Signs

• Sudden death.
• Death in good condition.
• Depression.
• Fall on side, paddling of legs, arching of back, rapid deterioration and death, often in opisthotonus.

Post-mortem lesions

• Liver swollen.
• Punctate/diffuse haemorrhages.
• Kidneys and spleen swollen.
• Microscopically - focal necrosis, bile duct proliferation and inflammation.

Diagnosis

History, lesions, SN serology, isolation in CE (causes stunting of 9 day embryo).

Differentiate from Duck plague (viral enteritis), Duck septicaemia (anatipestifer), coccidiosis, Newcastle disease, Influenza and a 'Type II Variant' hepatitis caused by Astrovirus.

Treatment

Antiserum, 0.5 ml serum of recovered birds given intramuscularly.

Prevention

Vaccination and/or antiserum, breeder vaccination. Live, only slightly attenuated vaccine is applied at day old by foot web stab and may be repeated in breeding birds to provide maternal immunity.