Newcastle Disease, Other Avian Paramyxoviruses, and Avian Metapneumovirus Infections

This chapter focuses on viruses of avian paramyxovirus serotype-1 (APMV-1). All isolates of APMV-1 are of one serotype and are referred to as Newcastle disease viruses (NDVs). The virulent NDVs seem to be the major exception of a wild bird reservoir, with the virulent viruses being endemic in poultry and domestic and feral pigeons. NDV strains can replicate in primary cells and cell lines of multiple species. For effective disease management, it is important to be able to identify birds that are infected with NDV and distinguish vaccine viruses from virulent viruses. The clinical diseases that may result from avian metapneumovirus (aMPV) infections of turkeys or chickens have been termed turkey rhinotracheitis (TRT), avian pneumovirus infection of turkeys (APV), swollen head syndrome (SHS), and avian rhinotracheitis (ART), based on clinical signs and lesions. Both live attenuated and inactivated aMPV vaccines are available commercially for use in turkeys and chickens.