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Type Species |
(MeV) |
Previously, the lack of a neuraminidase was a defining characteristic of the genus Morbillivirus, but this activity has recently been demonstrated for RPV. Member viruses exhibit greater amino acid sequence relatedness within the genus than with respiroviruses or rubulaviruses. They have an identical gene order, number of transcriptional elements and size of intergenic sequences with members of the genus Respirovirus (Fig. 2). All morbilliviruses have a P/C/V transcription unit with RNA editing like respiroviruses, namely the templated exact-copy mRNA encodes P and the predominant edited mRNA form (1 G added) encodes V. All morbilliviruses produce both intracytoplasmic and intranuclear inclusion bodies which contain viral ribonucleocapsids. Viruses crossreact in serological tests. Sialic acid does not appear to be a receptor for morbilliviruses. Narrow host-range distribution of receptor defines susceptibility of organisms to infection. For measles virus one receptor is CD46.
List of Species Demarcation Criteria in the Genus
The morbilliviruses are distinguished by host range, genetic (sequence) and antigenic differences. There is a low to moderate degree of sequence relatedness between members, depending on the protein (for example, the N protein of MeV is 65% related to that of CDV, viruses which represent two branches of the genus. Cross-neutralization and cross-protection also occurs between members of the genus, although members can also be distinguished on that basis. MeV infects primates, CDV infects members of Order Carnivora, and RPV and Peste-des-petits-ruminants virus (PPRV) infect members of Order Artiodactyla (even toed ungulates), especially ruminants and swine. PPRV is distinguished from RPV by sequence analysis (the N protein of PPRV shares 68-72% identity with that of MeV, RPV or CDV), and because it does not readily infect cattle. Phocine distemper virus (PDV) is most closely related to CDV and is distinguished by host range and sequence divergence. Dolphin and porpoise distemper viruses are closely related viruses which are most closely related to RPV and MeV: these viruses are distinguished by host range and sequence divergence.
Official virus species names are in italics. Tentative virus species names, alternative names ( ), strains or serotypes are not italicized. Virus names, genome sequence accession numbers [ ], and assigned abbreviations ( ) are:
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Canine distemper virus |
[L13194, M12669, M21849, M32418, Y09629] |
(CDV) |
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Cetacean morbillivirus virus |
[X75961, X80757, Z30086/87] |
(CeMV) |
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Measles virus (Edmonston virus) |
[Z66517, K01711, X16565, Y09629] |
(MeV) |
|
Peste-des-petits-ruminants virus |
[L39878, Z37017, Z81358] |
(PPRV) |
|
Phocine distemper virus (Seal distemper virus) |
[D10371, Y09630] |
(PDV) |
|
Rinderpest virus |
[X68311, E01799, E01798, X98291] |
(RPV) |
Tentative Species in the Genus
None reported.
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