Family: Nairoviridae
Genus: Orthonairovirus
Distinguishing features
The consensus terminal nucleotide sequences of the L, M, and S genome segments are typically characterized by a genus-specific 5′ genomic segment terminus 5′-UCUCAAAGA-3′ and 3′ genomic segment terminus of 5′-UCUUUGAGA-3′ ; however several members of the Orthonairovirus genus have termini that differ by one nucleotide. Glycoprotein (GP) subunits GN and GC and non-structural proteins are encoded as a precursor polyprotein by the M RNA. Genetic reassortment has been demonstrated between viruses belonging to the same species but not between members of different species. Of the 15 species within this genus, viruses of all but two species (Hughes orthonairovirus and Sakhalin orthonairovirus) have been detected in mammals. Of those members with known vectors, the majority of viruses within this genus are transmitted by ticks to mammalian hosts or birds. Some viruses are transmitted transovarially in arthropods.
Virion
See discussion under family description.
Genome organization and replication
The orthonairovirus genome consists of three single-stranded, negative-sense RNA molecules, termed S (small), M (medium), and L (large). These RNAs encode three different proteins: S RNA encodes N, the M RNA encodes the viral glycoprotein precursor (GPC), and the L RNA encodes the large protein (L) with its RNA-directed RNA polymerase (RdRP) domain in the virus-complementary sense RNA (Figure 1. Orthonairovirus).
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Figure 1. Orthonairovirus. Schematic representation of orthonairovirus genome organization. |
For further details see discussion under family description.
Biology
See discussion under family description.
Derivation of names
Orthonairovirus: from the Ancient Greek ὀρθός (orthós), meaning upright or straight and Nairobi, from Nairobi (Kenya) where Nairobi sheep disease virus was first isolated, and virus, suffix for a genus.
Species demarcation criteria
Demarcation of genera is based upon considerations of phylogeny, significant differences in member virus genome architecture, virion antigenicity, and virus ecology (e.g., host range, pathobiology, and transmission patterns.
Phylogenetic relationships
Phylogenetic relationships across the genus have been estimated using maximum likelihood trees generated from complete and partial protein sequences (Figure 4. Nairoviridae).
Member Species
The Member Species table enumerating important virus exemplars classified under each species of the genus is provided at the bottom of the page.
Related, unclassified viruses
Virus name |
Accession number |
Virus abbreviation |
Ahun virus |
Not available (Dacheux et al., 2014) |
|
Bakel virus |
Not available |
BAKV |
Elliðaey virus |
Not available (Moss et al., 1986) |
|
Foula virus |
Not available (Nuttall et al., 1986) |
|
Fraser Point virus |
Not available |
FPV |
Garm virus |
Not available (Lvov et al., 2015) |
|
Grímsey virus |
Not available (Moss et al., 1986) |
|
Inner Farne Island virus |
Not available (Nuttall et al., 1986) |
|
Island of May virus |
Not available (Nuttall et al., 1986) |
|
Kachemak Bay virus |
Not available (Ritter and Feltz 1974) |
KBV |
Kao Shuan virus |
Not available (Doherty et al., 1976) |
KSV |
Meram virus |
S: MN972596+; |
|
Mykines virus |
Not available (Nuttall et al., 1986) |
|
Nàyǔn tick nairovirus |
S: KP141755 |
NTNV |
Omo virus |
Not available (Rodhain et al., 1985) |
OMOV |
Paramushir virus |
PARV |
|
Pathum Thani virus |
Not available (Bishop et al., 1980) |
PTHV |
Pretoria virus |
Not available (Converse et al., 1975) |
PREV |
Puffin Island virus |
Not available (Gould et al., 1983) |
PIV |
Rondônia virus |
|
|
Vinegar Hill virus |
VINHV |
Virus names and virus abbreviations are not official ICTV designations.
+Not currently released. The Meram sequence are available in the sequence alignments on the Resources page.
*Coding region sequences incomplete.