Box 1 | Classification of henipaviruses

Viruses in the family Paramyxoviridae are classified in two subfamilies, Paramyxovirinae and Pneumovirinae. The latter subfamily contains two genera, Pneumovirus and Metapneumovirus. The number of genera in the Paramyxovirinae was increased in 2002 from three (Respirovirus, Morbillivirus and Rubulavirus) to five by the addition of two new genera, Avulavirus and Henipavirus¹³³. The Avulavirus genus contains avian paramyxoviruses that were previously classified in the Rubulavirus genus, and the Henipavirus genus was created to accommodate Hendra virus and Nipah virus.

The phylogenetic tree shown here is based on an alignment of the deduced amino-acid sequence of the N gene of selected Paramyxovirinae subfamily members using the Neighbour-Joining method (see the genome organization of henipaviruses in Fig. 2). Viruses are grouped according to genus and abbreviated as follows. Morbillivirus genus: MeV (measles virus), CDV (canine distemper virus); Henipavirus genus: HeV (Hendra virus), NiV (Nipah virus); Respirovirus genus: SeV (Sendai virus), hPIV3 (human parainfluenza virus 3); Avulavirus genus: NDV (Newcastle disease virus); Rubulavirus genus: hPIV2 (human parainfluenza virus 2), MaV (Mapuera virus), MuV (mumps virus), PIV4a (parainfluenza virus 4a), PoRV (porcine rubulavirus), SV5 (simian parainfluenza virus 5), SV41 (simian parainfluenza virus 41); and unclassified viruses SalV (Salem virus) and TPMV (Tupaia paramyxovirus).