Paramyxoviruses are a diverse group of enveloped viruses that infect vertebrates, primarily mammals and birds, as well as reptiles and sh. The family Paramyxoviridae is divided into two subfamilies, Paramyxovirinae and Pneumovirinae, the member species of which can be distinguished on the basis of

ultrastructure, genome organization, sequence re latedness of the encoded proteins, antigenic cross-reactivity, and biological properties of the attachment proteins (presence or absence of hemagglutinating and neuraminidase activities).6,7 Pneumovirinae contains two genera, Pneumovirus and Metapneumovirus, whereas Paramyxovirinae is separated into seven genera, Rubulavirus, Avulavirus, Respirovirus, Aquaparamyxovirus, Ferlavirus, Henipavirus, and Morbillivirus, the type species of which are mumps virus, Newcastle disease virus, Sendai virus, Atlantic salmon paramyxovirus, Fer de Lance paramyxovirus, Hendra virus, and measles virus, respectively.