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Type Species |
(SeV) |
Member viruses of the genus Respirovirus possess a hemagglutinin and a neuraminidase. These viruses have six transcriptional elements. All members encode a C protein. Unedited P mRNA encodes P and C, whereas insertion of a G nucleotide in P mRNA transcripts accesses the V ORF. Amino acid sequence relatedness within the genus ranges from low to high, depending on the protein, and always is higher than in comparisons with rubulaviruses and morbilliviruses. For example, within respiroviruses the N protein is 88% identical comparing HPIV-1 to SeV, its murine counterpart, and 63% identical compared to HPIV-2 or HPIV-3. Between genera, the N protein is 18% identical between HPIV-1 (Respirovirus) and the N protein of MuV or HPIV-2 or HPIV-4 (Rubulavirus), and 21% compared with that of MeV (Morbillivirus).
List of Species Demarcation Criteria in the Genus
HPIV-1 and HPIV-3 represent distinct serotypes defined by a lack of significant cross-neutralization and cross protection. Their gene maps are similar but not identical (HPIV-3 edits to make a D but not V protein, whereas HPIV-1 lacks editing). They share low to high sequence relatedness (see above). SeV is a murine HPIV-1 which is distinguished from HPIV-1 by host range: specifically, HPIV-1 is permissive and pathogenic in humans whereas in mice it grows poorly or not at all and is nonpathogenic, whereas SeV is highly permissive, transmissible and pathogenic for mice. The two viruses have considerable sequence relatedness (see above) and some antigenic similarity, but also can be clearly distinguished on either basis; also, HPIV-1 lacks editing and a V protein. BPIV-3 differs from HPIV-3 by host range, which overlap but exhibit specificity. For example, in humans HPIV-3 replicates efficiently, is easily transmissible and causes disease, whereas BPIV-3 is highly attenuated, nonpathogenic, and poorly transmissible. Furthermore, compared to HPIV-3, BPIV-3 is restricted 100 to 1000-fold in Old World primates. HPIV-3 and BPIV-3 exhibit considerable genetic and antigenic similarity, but also can clearly be distinguished on either basis. For example, HPIV-3 and BPIV-3 are 25% related antigenically by reciprocal cross-neutralization and hemagglutination inhibition studies. Also, BPIV-3 makes a V protein whereas HPIV-3 does not.
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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Bovine parainfluenza virus 3 |
[Y00114, Y00115, U31671] |
(BPIV-3) |
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Human parainfluenza virus 1 |
[M22347, M31228, M80818] |
(HPIV-1) |
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Human parainfluenza virus 3 |
[Z11575] |
(HPIV-3) |
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Sendai virus (Murine parainfluenza virus 1) |
[K01146, M19661, M30202-4, M76992, X00087] |
(SeV) |
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Simian virus 10 |
(SV-10) |
Tentative Species in the Genus
None reported.
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