The genus Avulavirus is one of seven genera in the family Paramyxoviridae and contains viruses that used to be classified in the genus Rubulavirus. In contrast to rubulaviruses, avulaviruses infect birds (hence the name "avulaviruses", a contraction of "avian rubulavirus") and translate protein V from an edited RNA transcript. Avulaviruses have a hemagglutinin-neuraminidase attachment protein and do not produce a non-structural protein C. The most important and best characterized avulavirus is Newcastle disease virus, a variant of avian paramyxovirus 1 (species Newcastle disease virus). Avulaviruses can be separated into distinct serotypes using hemagglutination assay and neuraminidase assay. All avulaviruses hemagglutinate chicken RBCs except for avian paramyxovirus 5 which does not hemag