40. Duck viral hepatitis.

Question 1

Duck Viral Hepatitis: Causing agents

• Family
• Genus

Answer 1

Duck Hepatitis A →

• Family: Picornaviridae
• Genus: Avihepatovirus
• Note that Astroviruses can cause duck hepatitis too*
• Note also that this is not to be confused with Duck Hep. B (older ducks)!*

Question 2

Duck Viral Hepatitis: Summary

Answer 2

• ​Serotype 1 → More pathogenic
• Serotype 2
• Serotype 3
• High resistance
• Circular; dsDNA; Enveloped

Question 3

Duck Viral Hepatitis: Epidemiology

Answer 3

• Shed in the faeces for several weeks
• Fast spread within flocks

Question 4

Duck Viral Hepatitis: Transmission

Answer 4

• Faeces
• Tracheal discharge

→ PO infection

Question 5

Duck Viral Hepatitis: Pathogenesis

Answer 5

PO infection → Replication in GI mucosa → Viraemia →

• Replication: Liver; Spleen; Kidney
• Ø Germinative infection; Long-lasting immunity; 2° Infection*

Question 6

Duck Viral Hepatitis: Incubation & CSx

Answer 6

Incubation time: 2-3 days

Seen in young duckings

• Peracute: Large-scale death within hours
• Acute: Depression; Lethargy; Ataxia; Spasmodic padding; Death

Question 7

Duck Viral Hepatitis: Pathology

Answer 7

• Liver: Enlarged; Yellow; Dystrophy; Necrosis; Haemorrhage
• Spleen: Enlarged; Mottled
• Kidney: Swollen; Plethoric; Nephrosis

Question 8

Duck Viral Hepatitis: Dx

Answer 8

• Epidemiology; CSx; Pathology; Histopathology
• Direct: PCR; IF; Isolation
• Indirect: VN; ELISA

Question 9

Duck Viral Hepatitis: DDx

Answer 9

• Duck hepatitis caused by Astroviruses
• Duck plague

Question 10

Duck Viral Hepatitis: Tx

Answer 10

Ø Treatment available

Question 11

Duck Viral Hepatitis: Prevention

Answer 11

• Epidemiological measures → Isolation at 4 weeks old
• Vaccine:
  
  • Inactivated: Layers → Booster
  • Attenuated:
    
    • ​Layers & Day-old ducklings
    • 7 Weeks old; 2-3 weeks before laying
  • Attenuated + Inactivated vaccination