Propagation of vaccine strain of duck enteritis virus in a cell line of duck origin as an alternative production system to propagation in embryonated egg

Duck virus enteritis (DVE) also known as duck plague, is a viral infection of ducks caused by duck enteritis virus (DEV). The control of the disease is mainly done by vaccination with a chicken embryo-adapted live virus that is known to be poorly immunogenic and affords partial protection. Further, the risk of harboring other infectious agents in the embryo particularly the deadly and zoonotic avian influenza virus is also high. In this paper, we report propagation of a chicken embryo-adapted vaccine strain of duck enteritis virus in duck embryo fibroblast (DEF) cell line. Thirty serial passages were done in DEF cell that made the vaccine virus further attenuated which was tested in ducks. The growth behaviors of the virus in DEF cells were studied and at 30th passage level the virus titre was found to be 10^6.8 TCID₅₀/ml. Ducks were immunized with this virus and challenged after 21 days with high dose of virulent DEV. All the immunized ducks withstood challenge with no clinical symptoms in any of the ducks while all the control ducks died. DEF cell which is free from other infectious agents appears to be a good system for cultivation of duck enteritis virus vaccine strain.