An outbreak of duck hepatitis type II in commercial ducks.

Investigation of a disease causing up to 50% mortality in 6 to 14-day-old ducks and up to 25% in 4 to 6-week-old ducks, resulted in the detection and isolation of an astrovirus-like agent. The virus was detected by electron microscopy in the livers of infected ducks and isolated in the amniotic-sac of embryonating specific pathogen free chicken eggs. The clinical, postmortem and histopathological findings resembled duck hepatitis type I. However, the results of laboratory investigations suggested that the disease was due to duck hepatitis type II. Inoculation of ducks with a duck hepatitis type II vaccine resulted in protection against experimental challenge with the astrovirus-like isolate.