The family Paramyxoviridae is further classified into two subfamilies Paramyxovirinae and Pneumovirinae , which not only include a number of older, well studied human and animal pathogens , but also newly emerged agents such as Hendra virus (HeV) and Nipah virus (NiV) as well as the most recently identified member Cedar Virus (CedPV). Although these newly emerged viruses appear to retain many of the genetic and biological properties of other members of their subfamily, Paramyxovirinae, they also have a number of unique characteristics in their subfamily ; both NiV and HeV share antigenic cross-reactivity with each other but not with any other members of the Paramyxovirinae subfamily.