Duck Hepatitis Type 2 Associated with an Astrovirus

Abstract

A disease of ducks, characterised by hepatitis, caused losses of up to 50% in 6 to 14 day—old—ducks and up to 25% in 4 to 6-week old ducks. During the period under investigation total losses exceeded 40,000 ducks. The affected ducks were the offspring of parents that had received duck hepatitis type 1 vaccine.

Examination of livers and faeces from infected ducks by electron microscopy resulted in the detection of numerous astrovirus-like particles. Repeated passage in the amniotic sac of embryonating specific-pathogen-free chicken eggs resulted in the isolation and detection of the astrovirus in the embryo livers.

The results of cross protection and challenge tests indicate that the astrovirus and duck hepatitis type 2 virus are antigenically similar. Laboratory investigations with an attenuated chicken embryo adapted duck hepatitis type 2 vaccine have shown that the vaccine confers protection against challenge with the duck astrovirus.

It is suggested that the disease known as duck hepatitis type 2 is caused by an astrovirus and hereafter should be reffered to as duck astrovirus infection.