Paramyxoviridae is a family of viruses in the order Mononegavirales. Vertebrates serve as natural hosts; no known plants serve as vectors. Currently, 49 species are placed in this family, divided among seven genera. Diseases associated with this negative-sense, single-stranded RNA virus family include measles, mumps, and respiratory tract infections. Paramyxoviridae is a family of viruses in the order Mononegavirales. Vertebrates serve as natural hosts; no known plants serve as vectors. Currently, 49 species are placed in this family, divided among seven genera. Diseases associated with this negative-sense, single-stranded RNA virus family include measles, mumps, and respiratory tract infections.