Electron microscopic characterization of duck plague virus

A virus [duck plague Long Island virulent virus (DPLIVV)] was isolated from ducks in a recent disease outbreak on farms on Long Island, New York. This disease exhibited characteristics similar to duck plague, a disease in ducks endemic to the Netherlands and India and not previously reported in the United States. An attenuated strain of the duck plague virus from the Netherlands was studied morphologically by electron microscopy. Its infectivity for duck embryo cell cultures was also studied. The DPLIVV and the Holland strain were morphologically identical. Furthermore, enzymatic digestion of methacrylate-embedded thin sections of mature virus particles showed that both Holland duck plague-attenuated virus and DPLIVV contained deoxyribonucleic acid. The dimensions of the mature cytoplasmic particle; nucleocapsid diameter ca. 75 micron, envelope diameter ca. 181 micron, and other characteristics would presumably place duck plague virus in the herpesvirus group.